Merge branch 'worktree-hooks-a-taxonomy' into worktree-hooks-b-bash-seam
This commit is contained in:
Tianyi Cui
@@ -134,13 +134,14 @@ forever:
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wait for queued messages (idle)
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emit agent/status(running)
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TURN (error-contained — a throwing plugin ends the turn, never the loop):
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drain queued → 'turn/start' → session('user/message'…) → emit agent/turn-start
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drain queued → 'turn/start' → session('user/message'…) ⟵ durable turn boundary (no agent/* mirror)
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STEP loop:
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drain steering (late steering from previous step's listeners)
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session('step/start') ⟵ durable step boundary (no agent/* mirror)
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assembly = ctx.systemPrompt.assemble() ⟵ waterfall system-prompt/assemble
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await ctx.serial('agent/pre-step') ⟵ surface mutation (compaction) OUTSIDE the step
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session('step/start') ⟵ durable step boundary (no agent/* mirror)
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req = {model, system, tools, messages: session.deriveMessages(), signal}
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req = waterfall agent/request ⟵ hooks, compaction, model switch
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req = waterfall agent/request ⟵ hooks, model switch
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stream ctx.llm.stream(req) ⟵ waterfall llm/stream (raw chunks)
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session('assistant/chunk'); emit agent/stream-chunk
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if assembler.finish is error/aborted: throw ⟵ adapter's in-band error path →
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@@ -158,7 +159,7 @@ forever:
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steering pending forces cont = true (from continuation listeners OR from
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step/end session-event listeners — the /goal pattern; hasSteering override)
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if !cont: break
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session('turn/end'); emit agent/turn-end
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session('turn/end') ⟵ durable turn boundary (no agent/* mirror)
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await ctx.parallel('session/flush', session) ⟵ durability checkpoint (failure
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reported via agent/error, not fatal)
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leftover steering re-enqueued as queued messages ⟵ steering is never stranded
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@@ -169,7 +170,7 @@ Error containment: a throwing `agent/turn-continuation` listener or a broken ste
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Turn-end reasons: a turn ends with one `TurnEndReason` — `completed`, `aborted`, `error`, `disposed`, or `max-tokens`. `max-tokens` mirrors the model-call `FinishReason` of the same name (DeepSeek's `length`): a step that hit the output-token ceiling makes the turn end `max-tokens` rather than `completed`, by the rule *any `max-tokens` step in the turn surfaces as `max-tokens`* (a continuation plugin may run further steps after one, but the cut-short fact wins; the `disposed`/`aborted`/`error` outcomes still take precedence). This lets a consumer distinguish a clean stop from a truncated one (the ACP bridge maps it to the `max_tokens` stop reason). `TurnEndReason` is merge-extensible; `refusal` and `max_turn_requests` are the next variants to add when an adapter/loop first emits them.
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A failure that happens once the turn is already closed has no in-turn position for a turn-end error reason (the turn already ended). So a rejecting `session/flush` (the post-`turn/end` durability checkpoint) and a throwing `agent/turn-end` listener are reported via `agent/error` + the logger only, NOT as a session event; the turn stays balanced and the persistence backend keeps its buffered events for the next flush.
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A failure that happens once the turn is already closed has no in-turn position for a turn-end error reason (the turn already ended). So a rejecting `session/flush` (the post-`turn/end` durability checkpoint) is reported via `agent/error` + the logger only, NOT as a session event; the turn stays balanced and the persistence backend keeps its buffered events for the next flush.
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**Turn-enclosure invariant**: every session event lives inside a turn (between a `turn/start` and its `turn/end`). The loop appends queued `user/message` events *after* `turn/start`, and an idle `agent.inject()` wraps its `context/message` in a one-shot `injection` turn. This makes the turn the single durability/replay boundary: a persistence backend can treat anything after the last `turn/end` as an interrupted-crash tail without risking the loss of legitimately-recorded between-turn context. The `dsh-invariants` plugin enforces it in dev (a message event outside an open turn throws). See [the turn-enclosure invariant](rfc/implemented/architecture/2026-06-15-turn-enclosure-invariant.md).
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@@ -195,10 +196,10 @@ Every MVP feature (including the TODO-marked ones), with the mechanism that impl
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|---|---|
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| Hook system (user + project level) | listeners on `agent/request`, `agent/step-result`, `tools/execute`, `agent/turn-continuation`; a hooks plugin bridges config files to shell commands |
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| `/goal` | force-continue via `agent/turn-continuation` + `steer()` reminders |
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| `/loop` | on `agent/turn-end`, `send()` the next iteration; or force-continue |
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| Dynamic workflow | orchestrator plugin on `agent/turn-end` (or the `step/end` session event) driving `send`/`steer` (+ sub-agents later) |
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| `/loop` | on the `turn/end` session event, `send()` the next iteration; or force-continue |
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| Dynamic workflow | orchestrator plugin on the `turn/end` (or `step/end`) session event driving `send`/`steer` (+ sub-agents later) |
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| Queued + steering messages | core `Agent.send()` / `Agent.steer()` |
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| Context compaction (auto + manual) | the `ctx.compact` seam ([dsh-compact](../packages/compact/compact)): a backend summarizes an older surface range into a single `user/message` `replace` op, bracketed by log-only `compact/*` events; auto = check token pressure at turn boundaries, manual = a `/compact` tool. See the [compaction capability-seam RFC](rfc/proposed/feature/2026-06-18-compaction-capability-seam.md) |
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| Context compaction (auto + manual) | the `dsh-compact` seam (`ctx.compact`) + a backend (`dsh-compact-basic`) on the serial `agent/pre-step` seam: a backend summarizes an older surface range into a single `user/message` `replace` op, bracketed by log-only `compact/*` events; auto = check token pressure before each step — runaway-turn survival, manual = a (deferred) `/compact` tool invoking the same `ctx.compact` routine. See the [compaction capability-seam RFC](rfc/implemented/feature/2026-06-18-compaction-capability-seam.md) |
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| System prompt configurability | `ctx.systemPrompt.section()` with ordering |
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| AGENTS.md (root) | a section provider reading the file |
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| AGENTS.md (subdir, on-touch) + file-change notices | `agent.inject()` from a watcher / tool-result listener |
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@@ -226,6 +227,6 @@ Code skeletons for the three plugin shapes (tool, hook/permission-gate, UI) and
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Tracked here deliberately — each is designed-for but not implemented:
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- **Inter-agent channels beyond delegation** (shared state, streaming child output, background/poll semantics) remain out of scope for the current `ctx.subagents` seam.
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- **Compaction implementation** (auto thresholds, summarization prompts) on the `agent/request` seam, with its session-event types added by declaration merging.
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- **Compaction** — the `dsh-compact` seam (`ctx.compact`) and the `dsh-compact-basic` backend exist (auto thresholds, summarization on the serial `agent/pre-step` seam, `compact/*` session events via declaration merging). The model-facing `/compact` consumer tool is still deferred. See [the compaction capability-seam RFC](rfc/implemented/feature/2026-06-18-compaction-capability-seam.md).
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- **Parallel tool execution** (concurrency-safety hints on ToolDefinition).
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- **Session branching/tree** (pi-style entry tree) if needed beyond seed-based forking.
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@@ -56,7 +56,7 @@ export function apply(ctx: Context) {
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## A client-driver plugin (external protocol bridge)
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A *client driver* is a UI plugin whose "user" is another program speaking a wire protocol rather than a human at a terminal. It owns the process's stdio (so it must run with **no stdout logger** — every non-protocol byte corrupts the stream), creates/resumes agents on demand through the `dsh-agent` factory seam, translates harness events (`session/event`, `agent/*`) into outbound protocol messages, and translates inbound requests back into `agent.send()` / `agent.cancel()`. Two harness-specific contracts make it correct: resolve each request exactly once off a settle signal (the turn can end without its `agent/turn-end` event firing — fall back through the logged `turn/end` record), and tear each agent down through its `AgentHandle.dispose()` (which stops the loop, `await`s its exit, and unregisters), not just `cancel()` — disposal must *reach* quiescence, not merely request it.
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A *client driver* is a UI plugin whose "user" is another program speaking a wire protocol rather than a human at a terminal. It owns the process's stdio (so it must run with **no stdout logger** — every non-protocol byte corrupts the stream), creates/resumes agents on demand through the `dsh-agent` factory seam, translates harness events (`session/event`, `agent/*`) into outbound protocol messages, and translates inbound requests back into `agent.send()` / `agent.cancel()`. Two harness-specific contracts make it correct: resolve each request exactly once off a settle signal (settle from the durable `turn/end` session event — the boundary is a session event, not an `agent/*` mirror — with `agent/status` as the fallback if a peer listener starved yours), and tear each agent down through its `AgentHandle.dispose()` (which stops the loop, `await`s its exit, and unregisters), not just `cancel()` — disposal must *reach* quiescence, not merely request it.
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`packages/ui/acp` is the worked example: it bridges the agent to the Agent Client Protocol (JSON-RPC over stdio) so Zed and other ACP editors can drive it. See its README for the full method surface and the deferred-permission-gate note.
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||||
|
||||
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@@ -11,7 +11,7 @@ The **harness tier** below (the `@deepseek-ai/dsh-*` packages) is the vocabulary
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||||
|
||||
## Events
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||||
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||||
Dispatch modes: **emit** (fire-and-forget), **waterfall** (each listener gets `next()` and may transform or veto — see [waterfall semantics](../architecture.md#cordis-waterfall-semantics-important)), **parallel** (awaited fan-out, no veto).
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Dispatch modes: **emit** (fire-and-forget), **waterfall** (each listener gets `next()` and may transform or veto — see [waterfall semantics](../architecture.md#cordis-waterfall-semantics-important)), **parallel** (awaited fan-out; all listeners run), **serial** (awaited in registration order until one returns a bail value — anything other than `null`, `false`, or `undefined`).
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### `agent/*`
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@@ -25,7 +25,7 @@ An agent was registered in the AgentRegistry and is ready to receive messages.
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||||
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||||
Types: [Agent](../core-data-structures/core.md)
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Source: [`packages/core/agent/src/types.ts:165`](../../packages/core/agent/src/types.ts)
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Source: [`packages/core/agent/src/types.ts:164`](../../packages/core/agent/src/types.ts)
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#### `agent/disposed` — emit
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@@ -37,7 +37,7 @@ An agent was disposed and removed from the registry; its fiber and any in-flight
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Types: [Agent](../core-data-structures/core.md)
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Source: [`packages/core/agent/src/types.ts:171`](../../packages/core/agent/src/types.ts)
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Source: [`packages/core/agent/src/types.ts:170`](../../packages/core/agent/src/types.ts)
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#### `agent/error` — emit
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@@ -49,7 +49,21 @@ A step or turn errored. The loop reports a failure here (plus the logger) even w
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Types: [Agent](../core-data-structures/core.md)
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Source: [`packages/core/agent/src/types.ts:245`](../../packages/core/agent/src/types.ts)
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Source: [`packages/core/agent/src/types.ts:263`](../../packages/core/agent/src/types.ts)
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#### `agent/pre-step` — serial
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Awaited pre-step surface-mutation checkpoint, fired once per step AFTER `turn/start` (and after the prior step closed) but BEFORE this step's `step/start` — so anything a listener appends lands OUTSIDE the step, between `turn/start`/`step/end` and the upcoming `step/start`. `step` is the number of the step about to start. The loop awaits `ctx.serial('agent/pre-step', …)` after assembling the system prompt, then opens the step and derives the request history ONCE from whatever the surface now holds. This is where compaction belongs: it mutates the session surface in place (shadowing an older range with a summary node) with its log-only `compact/*` records cleanly outside any step, and the single subsequent derive reflects the mutation — so there is no double-derive and no listener can see (or be expected to act on) an assembled `messages` array that does not exist yet.
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Serial (awaited in registration order), not a waterfall: a listener mutates the surface as a side effect; there is nothing to transform, but the loop must wait for the mutation to complete before opening the step and deriving. Cordis `serial` bails early if a listener returns a bail value; this event is typed and documented as `void`, so listeners must not return a semantic veto value. `fullSystemPrompt` is the assembled prompt a listener needs to measure pressure (the system prompt counts toward the budget). `signal` cancels any in-flight work a listener starts (e.g. a summarization model call).
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```ts cordis-catalog
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'agent/pre-step'(agent: Agent, turn: number, step: number, fullSystemPrompt: string, signal: AbortSignal): Promise<void> | void
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```
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Types: [Agent](../core-data-structures/core.md)
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Source: [`packages/core/agent/src/types.ts:223`](../../packages/core/agent/src/types.ts)
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#### `agent/queued` — emit
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@@ -61,11 +75,11 @@ A message entered the agent's inbox (queued or steering). `source` is the resolv
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Types: [Agent](../core-data-structures/core.md) · [ContentBlock](../core-data-structures/core.md) · [MessageSource](../core-data-structures/core.md)
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|
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Source: [`packages/core/agent/src/types.ts:184`](../../packages/core/agent/src/types.ts)
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Source: [`packages/core/agent/src/types.ts:183`](../../packages/core/agent/src/types.ts)
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#### `agent/request` — waterfall
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Waterfall: mutate the fully-assembled GenerateOptions before the model call (hooks, compaction, model switching, tool filtering, …). Call `next()` to delegate, or return without it to short-circuit.
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Waterfall: mutate the fully-assembled GenerateOptions before the model call (hooks, model switching, tool filtering, …). Call `next()` to delegate, or return without it to short-circuit. For surface mutation that must precede history derivation (compaction), use agent/pre-step instead — by the time this fires, `options.messages` is already derived.
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```ts cordis-catalog
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'agent/request'(agent: Agent, turn: number, step: number, options: GenerateOptions, next: () => Promise<GenerateOptions>): Promise<GenerateOptions>
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@@ -73,7 +87,7 @@ Waterfall: mutate the fully-assembled GenerateOptions before the model call (hoo
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|
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Types: [Agent](../core-data-structures/core.md) · [GenerateOptions](../core-data-structures/core.md)
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Source: [`packages/core/agent/src/types.ts:214`](../../packages/core/agent/src/types.ts)
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Source: [`packages/core/agent/src/types.ts:232`](../../packages/core/agent/src/types.ts)
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#### `agent/status` — emit
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@@ -85,7 +99,7 @@ Agent status changed (`idle` ⇄ `running`, or → `disposed`). Drive lifecycle
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Types: [Agent](../core-data-structures/core.md)
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|
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Source: [`packages/core/agent/src/types.ts:178`](../../packages/core/agent/src/types.ts)
|
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Source: [`packages/core/agent/src/types.ts:177`](../../packages/core/agent/src/types.ts)
|
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#### `agent/steering` — emit
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@@ -97,7 +111,7 @@ Steering content was injected into a running turn.
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|
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Types: [Agent](../core-data-structures/core.md) · [ContentBlock](../core-data-structures/core.md) · [MessageSource](../core-data-structures/core.md)
|
||||
|
||||
Source: [`packages/core/agent/src/types.ts:239`](../../packages/core/agent/src/types.ts)
|
||||
Source: [`packages/core/agent/src/types.ts:257`](../../packages/core/agent/src/types.ts)
|
||||
|
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#### `agent/step-result` — waterfall
|
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|
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@@ -109,7 +123,7 @@ Waterfall: post-process the assembled assistant Message before tool dispatch (va
|
||||
|
||||
Types: [Agent](../core-data-structures/core.md) · [Message](../core-data-structures/core.md)
|
||||
|
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Source: [`packages/core/agent/src/types.ts:220`](../../packages/core/agent/src/types.ts)
|
||||
Source: [`packages/core/agent/src/types.ts:238`](../../packages/core/agent/src/types.ts)
|
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|
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#### `agent/stream-chunk` — emit
|
||||
|
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@@ -121,7 +135,7 @@ A raw StreamChunk arrived from the model (token-level UI/log feed).
|
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|
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Types: [Agent](../core-data-structures/core.md) · [StreamChunk](../core-data-structures/llm-streaming.md)
|
||||
|
||||
Source: [`packages/core/agent/src/types.ts:234`](../../packages/core/agent/src/types.ts)
|
||||
Source: [`packages/core/agent/src/types.ts:252`](../../packages/core/agent/src/types.ts)
|
||||
|
||||
#### `agent/turn-continuation` — waterfall
|
||||
|
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@@ -133,31 +147,7 @@ Waterfall: override the turn-continuation decision. The default (computed by the
|
||||
|
||||
Types: [Agent](../core-data-structures/core.md)
|
||||
|
||||
Source: [`packages/core/agent/src/types.ts:227`](../../packages/core/agent/src/types.ts)
|
||||
|
||||
#### `agent/turn-end` — emit
|
||||
|
||||
A turn ended. `reason` distinguishes a clean stop from a truncated, aborted, failed, disposed, or crash-interrupted one (`completed` | `aborted` | `error` | `disposed` | `max-tokens` | `interrupted`); the reason union is merge-extensible, so a plugin can add further variants.
|
||||
|
||||
```ts cordis-catalog
|
||||
'agent/turn-end'(agent: Agent, turn: number, reason: TurnEndReason): void
|
||||
```
|
||||
|
||||
Types: [Agent](../core-data-structures/core.md) · [TurnEndReason](../core-data-structures/session.md)
|
||||
|
||||
Source: [`packages/core/agent/src/types.ts:205`](../../packages/core/agent/src/types.ts)
|
||||
|
||||
#### `agent/turn-start` — emit
|
||||
|
||||
A turn began. `turn` is the 1-based turn number within the session.
|
||||
|
||||
```ts cordis-catalog
|
||||
'agent/turn-start'(agent: Agent, turn: number): void
|
||||
```
|
||||
|
||||
Types: [Agent](../core-data-structures/core.md)
|
||||
|
||||
Source: [`packages/core/agent/src/types.ts:197`](../../packages/core/agent/src/types.ts)
|
||||
Source: [`packages/core/agent/src/types.ts:245`](../../packages/core/agent/src/types.ts)
|
||||
|
||||
### `llm/*`
|
||||
|
||||
@@ -183,7 +173,7 @@ A session was created in the store.
|
||||
'session/created'(session: Session): void
|
||||
```
|
||||
|
||||
Source: [`packages/core/session/src/index.ts:33`](../../packages/core/session/src/index.ts)
|
||||
Source: [`packages/core/session/src/index.ts:34`](../../packages/core/session/src/index.ts)
|
||||
|
||||
#### `session/event` — emit
|
||||
|
||||
@@ -195,7 +185,7 @@ An event was appended to a session log (sync, fire-and-forget). This is the per-
|
||||
|
||||
Types: [SessionEvent](../core-data-structures/core.md)
|
||||
|
||||
Source: [`packages/core/session/src/index.ts:39`](../../packages/core/session/src/index.ts)
|
||||
Source: [`packages/core/session/src/index.ts:40`](../../packages/core/session/src/index.ts)
|
||||
|
||||
#### `session/flush` — parallel
|
||||
|
||||
@@ -205,7 +195,7 @@ Awaited durability checkpoint. The agent loop awaits `ctx.parallel('session/flus
|
||||
'session/flush'(session: Session): Promise<void> | void
|
||||
```
|
||||
|
||||
Source: [`packages/core/session/src/index.ts:48`](../../packages/core/session/src/index.ts)
|
||||
Source: [`packages/core/session/src/index.ts:49`](../../packages/core/session/src/index.ts)
|
||||
|
||||
### `subagent/*`
|
||||
|
||||
@@ -349,11 +339,11 @@ Implementations MUST honor:
|
||||
- **Blocking**: no compaction begins while another is in progress for the same session. The recommended mechanism is the log-recorded lock — append `compact/start` before the slow work and `compact/end` after (even on failure) — so the lock is visible to replay and crash recovery.
|
||||
|
||||
```ts cordis-catalog
|
||||
abstract compactIfNeeded( session: Session, systemPrompt?: string, model?: string, signal?: AbortSignal, ): Promise<CompactionResult | null>
|
||||
abstract compactRegion( session: Session, start: number, end: number, model: string, signal?: AbortSignal, ): Promise<CompactionResult>
|
||||
abstract compactIfNeeded( agent: CompactAgentContext, turn: number, step: number, fullSystemPrompt: string, signal: AbortSignal, ): Promise<CompactionResult | null>
|
||||
abstract compactRegion( session: Session, start: number, end: number, agent: CompactAgentContext, turn: number, step: number, signal?: AbortSignal, ): Promise<CompactionResult>
|
||||
```
|
||||
|
||||
Source: [`packages/compact/compact/src/index.ts:57`](../../packages/compact/compact/src/index.ts)
|
||||
Source: [`packages/compact/compact/src/index.ts:63`](../../packages/compact/compact/src/index.ts)
|
||||
|
||||
### `ctx.llm` — `LlmService`
|
||||
|
||||
@@ -406,7 +396,7 @@ get(id: SessionId): Session | undefined
|
||||
list(): Session[]
|
||||
```
|
||||
|
||||
Source: [`packages/core/session/src/index.ts:321`](../../packages/core/session/src/index.ts)
|
||||
Source: [`packages/core/session/src/index.ts:322`](../../packages/core/session/src/index.ts)
|
||||
|
||||
### `ctx.subagents` — `SubagentService`
|
||||
|
||||
@@ -473,7 +463,7 @@ The framework surface every plugin inherits, beyond the harness vocabulary above
|
||||
### Inherited `ctx` members
|
||||
|
||||
- `ctx.on / ctx.once` — Register an event listener (disposable). ([`vendor/cordis/src/events.ts:29`](../../vendor/cordis/src/events.ts))
|
||||
- `ctx.emit / ctx.parallel / ctx.serial / ctx.bail / ctx.waterfall` — Dispatch an event (sync / awaited / first-non-nullish / veto-chain). ([`vendor/cordis/src/events.ts:29`](../../vendor/cordis/src/events.ts))
|
||||
- `ctx.emit / ctx.parallel / ctx.serial / ctx.bail / ctx.waterfall` — Dispatch an event (sync / awaited / first-bail / veto-chain). ([`vendor/cordis/src/events.ts:29`](../../vendor/cordis/src/events.ts))
|
||||
- `ctx.plugin / ctx.inject` — Load a plugin / declare required services. ([`vendor/cordis/src/registry.ts:144`](../../vendor/cordis/src/registry.ts))
|
||||
- `ctx.effect` — Register a disposable side effect tied to the fiber. ([`vendor/cordis/src/fiber.ts:9`](../../vendor/cordis/src/fiber.ts))
|
||||
- `ctx.get / ctx.set / ctx.provide / ctx.accessor / ctx.mixin` — Low-level service-store access and binding. ([`vendor/cordis/src/reflect.ts:7`](../../vendor/cordis/src/reflect.ts))
|
||||
|
||||
@@ -1,6 +1,6 @@
|
||||
# Compaction
|
||||
|
||||
The compaction seam — a [capability seam](../rfc/implemented/architecture/2026-06-13-capability-seams.md) split like bash: interface ([dsh-compact](../../packages/compact/compact), `ctx.compact`), implementation (a backend such as `dsh-compact-basic`, deferred), and consumer (a `/compact` tool, deferred). Compaction is **one optional capability**, not part of the agent-loop spine — so its vocabulary lives here, not in [core.md](core.md). A tokenizer- or template-based backend is a sibling package implementing the same interface. Unlike bash, the interface necessarily depends on `dsh-session` and `dsh-llm`: its verbs are defined over a `Session` and its output is the `ContentBlock` vocabulary (see the [compaction capability-seam RFC](../rfc/proposed/feature/2026-06-18-compaction-capability-seam.md)).
|
||||
The compaction seam — a [capability seam](../rfc/implemented/architecture/2026-06-13-capability-seams.md) split like bash: interface ([dsh-compact](../../packages/compact/compact), `ctx.compact`), implementation (a backend such as [dsh-compact-basic](../../packages/compact/compact-basic)), and consumer (a `/compact` tool, deferred). Compaction is **one optional capability**, not part of the agent-loop spine — so its vocabulary lives here, not in [core.md](core.md). A tokenizer- or template-based backend is a sibling package implementing the same interface. Unlike bash, the interface necessarily depends on `dsh-session` and `dsh-llm`: its verbs are defined over a `Session` and its output is the `ContentBlock` vocabulary (see the [compaction capability-seam RFC](../rfc/implemented/feature/2026-06-18-compaction-capability-seam.md)).
|
||||
|
||||
Source: [`packages/compact/compact/src/types.ts`](../../packages/compact/compact/src/types.ts)
|
||||
|
||||
@@ -11,7 +11,7 @@ Compaction extends [`SessionEventMap`](session.md) with three event types via de
|
||||
| Event | Payload | Role |
|
||||
|---|---|---|
|
||||
| `compact/start` | `{ turn }` | acquires the log-recorded lock |
|
||||
| `compact/summary` | `{ summary, shadowedRange, shadowedSeqs, shadowedTokenCount }` | provenance: the summary blocks, the shadowed seq range, and the estimated token count |
|
||||
| `compact/summary` | `{ summary, shadowedRange, shadowedSeqs, shadowedTokenCount }` | provenance: the summary blocks, the shadowed surface-boundary pair (`start`/`end` seqs — a position span, not a numeric interval), the shadowed seqs in surface order, and the estimated token count |
|
||||
| `compact/end` | `{ turn, error? }` | releases the lock (`error` set when summarization threw) |
|
||||
|
||||
The lock brackets the **whole** operation: `compact/start` is appended first, then summarization, the `compact/summary` provenance record, and the `user/message` replacement all land, and only then `compact/end`. Releasing the lock last turns a crash mid-operation into a detectable orphaned lock (a `compact/start` with no matching `compact/end`) rather than a `compact/end` that falsely claims compaction finished.
|
||||
@@ -32,9 +32,16 @@ interface CompactionResult {
|
||||
endSeq: number
|
||||
/** The summary content blocks produced by the backend. */
|
||||
summary: ContentBlock[]
|
||||
/** The seq range that was shadowed [start, end] inclusive. */
|
||||
/**
|
||||
* The surface-boundary pair that was shadowed: the seqs of the first
|
||||
* (`start`) and last (`end`) surface nodes of the replaced range. A
|
||||
* surface-POSITION span, not a numeric seq interval — after a prior replace
|
||||
* lands a fresh high-seq summary node at an older range's position, `start`
|
||||
* can be GREATER than `end`. {@link CompactionResult.shadowedSeqs} is the
|
||||
* authoritative set of shadowed nodes, in surface order.
|
||||
*/
|
||||
shadowedRange: { start: number; end: number }
|
||||
/** The seq numbers of all shadowed surface nodes. */
|
||||
/** The seqs of all shadowed surface nodes, in surface order. */
|
||||
shadowedSeqs: number[]
|
||||
/** Estimated token count of the shadowed content. */
|
||||
shadowedTokenCount: number
|
||||
@@ -43,4 +50,6 @@ interface CompactionResult {
|
||||
|
||||
## The service
|
||||
|
||||
`CompactService` (`ctx.compact`, abstract — defined in [`packages/compact/compact/src/index.ts`](../../packages/compact/compact/src/index.ts)) declares two abstract methods: `compactIfNeeded(session, systemPrompt?, model?, signal?)` checks token pressure and compacts an older range if the history is too large (returning `null` when nothing needs it), and `compactRegion(session, start, end, model, signal?)` forcibly summarizes surface nodes `[start, end]` into a single replacement node. Both take an optional `signal: AbortSignal` that a backend summarizing via `ctx.llm.stream()` must forward into the call's `GenerateOptions.signal`, so an abort or dispose tears down the in-flight summarization. The entire strategy — token estimation, retention policy, event sequencing, summarization — is a HOW decision owned by the implementation.
|
||||
`CompactService` (`ctx.compact`, abstract — defined in [`packages/compact/compact/src/index.ts`](../../packages/compact/compact/src/index.ts)) declares two abstract methods: `compactIfNeeded(agent, turn, step, fullSystemPrompt, signal)` checks token pressure and compacts an older range if the history is too large (returning `null` when nothing needs it), and `compactRegion(session, start, end, agent, turn, step, signal?)` forcibly summarizes surface nodes `[start, end]` into a single replacement node. `compactIfNeeded`'s parameters are all required — the loop's `agent/pre-step` checkpoint supplies the agent, lifecycle context, assembled `fullSystemPrompt`, and turn `signal`. A backend summarizing via `ctx.llm.stream()` must forward `signal` into the call's `GenerateOptions.signal`, so an abort or dispose tears down the in-flight summarization. The entire strategy — token estimation, retention policy, event sequencing, summarization — is a HOW decision owned by the implementation.
|
||||
|
||||
Auto-compaction runs on the serial `agent/pre-step` loop seam (fired once per step, after `turn/start` and BEFORE the step opens and its request history is derived), not the `agent/request` waterfall: compaction mutates the session surface in place — with its log-only `compact/*` records landing cleanly outside any step — and the loop derives the request from the already-compacted surface. Retention is turn-agnostic — the only structural guard is tool-pairing balance (a compacted region's edges are balanced cuts on the surface, so it never splits a step's tool-calls from their results), so a single runaway turn that alone exceeds the window compacts its own early closed steps rather than being retained verbatim. The backend that ships this (`dsh-compact-basic`) documents the retention walk, summary shrink validation, bounded re-compaction, and the crash/recoverable failure taxonomy.
|
||||
|
||||
@@ -205,7 +205,7 @@ type SessionEvent<T extends SessionEventType = SessionEventType> = {
|
||||
/**
|
||||
* Seq numbers of events that are provenance sources of this event
|
||||
* (e.g. the `assistant/chunk` seqs that built an `assistant/message`,
|
||||
* or the surface nodes shadowed by a compaction marker).
|
||||
* or the surface nodes shadowed by a compaction replace node).
|
||||
*/
|
||||
sourceEventSeqs?: number[]
|
||||
/** How this event entered the surface; absent for non-surface events. */
|
||||
@@ -306,7 +306,7 @@ interface Agent {
|
||||
}
|
||||
```
|
||||
|
||||
`AgentStatus` is `'idle' | 'running' | 'disposed'`. `AgentId` is a branded string. `AgentOptions` (`model?`, `systemPrompt?`) is merge-extensible — plugins add creation options by declaration merging. The `agent/*` event taxonomy (lifecycle, turn/step boundaries, the `agent/request`/`agent/step-result`/`agent/turn-continuation` waterfalls) is in [architecture.md § Event taxonomy](../architecture.md#event-taxonomy).
|
||||
`AgentStatus` is `'idle' | 'running' | 'disposed'`. `AgentId` is a branded string. `AgentOptions` (`model?`, `systemPrompt?`) is merge-extensible — plugins add creation options by declaration merging. The `agent/*` event taxonomy (lifecycle emits, the serial `agent/pre-step` surface-mutation seam, and the `agent/request`/`agent/step-result`/`agent/turn-continuation` waterfalls) is in [architecture.md § Event taxonomy](../architecture.md#event-taxonomy); turn/step boundaries are durable `session/event` records, not `agent/*` emits.
|
||||
|
||||
## `ToolDefinition`
|
||||
|
||||
|
||||
@@ -80,7 +80,7 @@ type SessionEvent<T extends SessionEventType = SessionEventType> = {
|
||||
/**
|
||||
* Seq numbers of events that are provenance sources of this event
|
||||
* (e.g. the `assistant/chunk` seqs that built an `assistant/message`,
|
||||
* or the surface nodes shadowed by a compaction marker).
|
||||
* or the surface nodes shadowed by a compaction replace node).
|
||||
*/
|
||||
sourceEventSeqs?: number[]
|
||||
/** How this event entered the surface; absent for non-surface events. */
|
||||
|
||||
113
docs/i18n/terminology.md
Normal file
113
docs/i18n/terminology.md
Normal file
@@ -0,0 +1,113 @@
|
||||
# Terminology
|
||||
|
||||
本表约定本仓库的中英术语统一译法。
|
||||
|
||||
| English | 中文 | 备注 |
|
||||
|---|---|---|
|
||||
| ACP | ACP | 首次出现可写：ACP（Agent Client Protocol） |
|
||||
| AI | AI | 首次出现可写：人工智能（AI） |
|
||||
| API | API | |
|
||||
| CLI | CLI | 首次出现可写：命令行界面（CLI） |
|
||||
| Cordis | Cordis | 保留英文 |
|
||||
| Function Calling | Function Calling | 首次出现可写：Function Calling（函数调用） |
|
||||
| HMR | HMR | 首次出现可写：热模块替换（HMR） |
|
||||
| JSON Schema | JSON Schema | |
|
||||
| JSONL | JSONL | |
|
||||
| lint | lint | |
|
||||
| loader | loader | |
|
||||
| LLM | LLM | 首次出现可写：大语言模型（LLM） |
|
||||
| MCP | MCP | |
|
||||
| RAG | RAG | 首次出现可写：检索增强生成（RAG） |
|
||||
| SDK | SDK | |
|
||||
| SSE | SSE | 首次出现可写：SSE（Server-Sent Events） |
|
||||
| agent | agent | 首次出现可写：agent（智能体） |
|
||||
| agent loop | agent loop | |
|
||||
| fiber | fiber | 首次出现可写：fiber（插件运行时） |
|
||||
| fixture | fixture | 指测试前置数据或环境 |
|
||||
| fork | fork | 保留英文 |
|
||||
| harness | harness | 保留英文 |
|
||||
| manifest | manifest | 描述模块或工具元数据的文件 |
|
||||
| schema DSL | schema DSL | |
|
||||
| schema | schema | 保留英文 |
|
||||
| seam | seam | 首次出现可写：seam（扩展点） |
|
||||
| skill | skill | 首次出现可写：skill（技能） |
|
||||
| spawn | spawn | 保留英文 |
|
||||
| steering | steering | 首次出现可写：steering（中途引导） |
|
||||
| subagent | subagent | 首次出现可写：subagent（子 agent） |
|
||||
| transcript | transcript | 首次出现可写：transcript（文本记录）；指会话渲染给用户或编辑器的完整文本，区别于事件日志（event log） |
|
||||
| waterfall | waterfall | 首次出现可写：waterfall（瀑布式事件） |
|
||||
| wire format | 协议格式 | 首次出现可写：协议格式（wire format） |
|
||||
| adapter contract | 适配器契约 | 首次出现可写：适配器契约（adapter contract） |
|
||||
| adapter | 适配器 | |
|
||||
| append-only | 仅追加 | |
|
||||
| artifact | 产物 | |
|
||||
| block | 块 | |
|
||||
| background task | 后台任务 | |
|
||||
| backend | 后端 | |
|
||||
| capability | 能力 | |
|
||||
| cancel | 取消 | |
|
||||
| checkpoint | 检查点 | |
|
||||
| chunk | 分片 | |
|
||||
| compaction | compaction | 首次出现可写：compaction（上下文压缩）；正文优先保留英文 |
|
||||
| consumer | 消费方 | |
|
||||
| content block | 内容块 | |
|
||||
| config | 配置 | |
|
||||
| context | 上下文 | |
|
||||
| context compaction | 上下文压缩 | 首次出现可写：上下文压缩（context compaction） |
|
||||
| coverage | 覆盖率 | |
|
||||
| crash recovery | 崩溃恢复 | |
|
||||
| dispose | dispose | 首次出现可写：dispose（释放资源）；正文优先保留英文 |
|
||||
| durability | 持久性 | |
|
||||
| event log | 事件日志 | |
|
||||
| event | 事件 | |
|
||||
| event stream | 事件流 | |
|
||||
| executor | 执行器 | |
|
||||
| extension | 扩展 | |
|
||||
| finish reason | 结束原因 | |
|
||||
| foreground run | 前台运行 | |
|
||||
| hook | 钩子 | |
|
||||
| implementation | 实现 | |
|
||||
| inference | 推理（inference） | 每次提及时保留英文括注，避免与 reasoning 混淆 |
|
||||
| injection | 注入 | |
|
||||
| interface | 接口 | |
|
||||
| integration | 集成 | |
|
||||
| memory | memory / 记忆 / 内存 | 按上下文区分：agent memory 译为“记忆”；resource/memory usage 译为“内存” |
|
||||
| message | 消息 | |
|
||||
| mod | 模组 | 区别于 module（模块）；plugin 译作「插件」 |
|
||||
| model provider | 模型提供方 | |
|
||||
| module | 模块 | |
|
||||
| permission | 权限 | |
|
||||
| persistence | 持久化 | |
|
||||
| pipeline | 流水线 | |
|
||||
| plugin | 插件 | mod 对应“模组” |
|
||||
| prompt | 提示词 | |
|
||||
| provider | 提供方 | |
|
||||
| provider-neutral | 提供方无关 | |
|
||||
| quality gate | 质量门禁 | |
|
||||
| registry | 注册表 | |
|
||||
| reasoning | 推理（reasoning） | 需要和 inference 区分时保留英文括注；`reasoning_content` 译为“思考内容” |
|
||||
| replay | 回放 | |
|
||||
| resume | 恢复 | |
|
||||
| runtime | 运行时 | |
|
||||
| sandbox | 沙箱 | |
|
||||
| service | 服务 | |
|
||||
| session | 会话 | |
|
||||
| session event | 会话事件 | |
|
||||
| snapshot | 快照 | |
|
||||
| spine | 主干 | |
|
||||
| step | 步骤 | |
|
||||
| stream | 流 | |
|
||||
| streaming | 流式输出 | |
|
||||
| system prompt | 系统提示词 | |
|
||||
| taxonomy | 分类体系 | |
|
||||
| token usage | token 用量 | |
|
||||
| thinking | thinking | API 字段保留；模型模式译为“思考” |
|
||||
| tool | 工具 | |
|
||||
| tool call | 工具调用 | |
|
||||
| tool result | 工具结果 | |
|
||||
| tool schema | 工具 schema | |
|
||||
| toolkit | 工具包 | |
|
||||
| turn | 轮次 | |
|
||||
| typecheck | 类型检查 | |
|
||||
| vocabulary | 词汇 | |
|
||||
| workflow | 工作流 | |
|
||||
@@ -23,6 +23,10 @@ graph TD
|
||||
llm-replay --> llm
|
||||
llm-replay --> session
|
||||
session-persistence --> session
|
||||
compact-basic --> agent
|
||||
compact-basic --> compact
|
||||
compact-basic --> llm
|
||||
compact-basic --> session
|
||||
invariants --> agent
|
||||
invariants --> llm
|
||||
invariants --> session
|
||||
@@ -109,6 +113,7 @@ graph TD
|
||||
| `compact` | `llm`, `session` |
|
||||
| `llm-replay` | `llm`, `session` |
|
||||
| `session-persistence` | `session` |
|
||||
| `compact-basic` | `agent`, `compact`, `llm`, `session` |
|
||||
| `invariants` | `agent`, `llm`, `session` |
|
||||
| `session-persistence-jsonl` | `session`, `session-persistence` |
|
||||
| `session-persistence-sqlite` | `session`, `session-persistence` |
|
||||
|
||||
@@ -44,14 +44,12 @@ Do NOT write one for a mechanical or local choice (a variable name, a one-file r
|
||||
| [Agent Client Protocol (ACP) support for external editors](proposed/feature/2026-06-14-acp-agent-client-protocol.md) | 2026-06-14 |
|
||||
| [Multiplex concurrent ACP sessions over one connection](proposed/feature/2026-06-14-acp-multi-session.md) | 2026-06-14 |
|
||||
| [Optional Code Mode — model writes TypeScript against an SDK of all tools](proposed/feature/2026-06-15-optional-code-mode.md) | 2026-06-15 |
|
||||
| [Compaction as a capability seam (abstract contract + basic backend)](proposed/feature/2026-06-18-compaction-capability-seam.md) | 2026-06-18 |
|
||||
|
||||
### Simplification
|
||||
|
||||
| Title | First proposed |
|
||||
|---|---|
|
||||
| [Unify the agent id and the session id](proposed/simplification/2026-06-20-unify-agent-and-session-id.md) | 2026-06-20 |
|
||||
| [Stop mirroring durable boundaries as agent events](proposed/simplification/2026-06-20-remove-agent-boundary-mirror-events.md) | 2026-06-20 |
|
||||
|
||||
### Architecture
|
||||
|
||||
@@ -83,6 +81,7 @@ Do NOT write one for a mechanical or local choice (a variable name, a one-file r
|
||||
| Title | First proposed |
|
||||
|---|---|
|
||||
| [Rich ACP bash rendering — the terminal card (`_meta`) and command classification](implemented/feature/2026-06-18-acp-terminal-and-tool-rendering.md) | 2026-06-18 |
|
||||
| [Compaction as a capability seam (abstract contract + basic backend)](implemented/feature/2026-06-18-compaction-capability-seam.md) | 2026-06-18 |
|
||||
| [Subagent capability seam](implemented/feature/2026-06-21-subagent-capability-seam.md) | 2026-06-21 |
|
||||
| [ACP subagent backend (out-of-process delegation)](implemented/feature/2026-06-22-acp-subagent-backend.md) | 2026-06-22 |
|
||||
| [The `todo_write` tool — model task list as event-sourced session state](implemented/feature/2026-06-29-todo-write-tool.md) | 2026-06-29 |
|
||||
@@ -97,6 +96,7 @@ Do NOT write one for a mechanical or local choice (a variable name, a one-file r
|
||||
| [Prune dead methods from the persistence seam](implemented/simplification/2026-06-20-prune-dead-seam-methods.md) | 2026-06-20 |
|
||||
| [Keep one public stop primitive](implemented/simplification/2026-06-20-public-agent-stop-surface.md) | 2026-06-20 |
|
||||
| [Fold trace-only session facts into load-bearing events](implemented/simplification/2026-06-20-collapse-trace-only-session-events.md) | 2026-06-20 |
|
||||
| [Stop mirroring durable boundaries as agent events](implemented/simplification/2026-06-20-remove-agent-boundary-mirror-events.md) | 2026-06-20 |
|
||||
|
||||
### Architecture
|
||||
|
||||
|
||||
@@ -37,4 +37,4 @@ Costs: `agent.inject()` while idle now writes three log lines instead of one, an
|
||||
|
||||
The rule is intentionally producer-enforced and dev-checked rather than reader-tolerated: a future backend (SQLite/WAL) inherits the same clean boundary for free, and a plugin that records an event outside a turn fails loudly in dev instead of silently losing data on the next reload.
|
||||
|
||||
The invariant also constrains where the loop may record an `error` event. A failure detected while a turn is open is appended INSIDE the turn (before `turn/end`); but a failure that surfaces once the turn is already closed — a rejecting `session/flush` (which runs as the post-`turn/end` durability checkpoint) or a throwing `agent/turn-end` listener (after `closeTurn` already appended `turn/end`) — has no in-turn position left. Appending an `error` there would land it past the last `turn/end`, exactly the crash-tail position a backend discards. So those post-turn failures are reported via the `agent/error` event and the logger only, never as a `SessionEvent`; the turn stays balanced and persistence keeps its buffered events for the next checkpoint. If durable operational diagnostics are ever needed, they belong on a separate telemetry channel, not the replayable session log.
|
||||
The invariant also constrains where the loop may record an `error` event. A failure detected while a turn is open is appended INSIDE the turn (before `turn/end`); but a failure that surfaces once the turn is already closed — a rejecting `session/flush`, which runs as the post-`turn/end` durability checkpoint — has no in-turn position left. Appending an `error` there would land it past the last `turn/end`, exactly the crash-tail position a backend discards. So that post-turn failure is reported via the `agent/error` event and the logger only, never as a `SessionEvent`; the turn stays balanced and persistence keeps its buffered events for the next checkpoint. If durable operational diagnostics are ever needed, they belong on a separate telemetry channel, not the replayable session log.
|
||||
|
||||
@@ -19,21 +19,17 @@ This is the foundational change in a stack that adds a Hooks subsystem; it estab
|
||||
**Three domains, one job each, with a single boundary rule.**
|
||||
|
||||
- **`session/*` — the durable, replayable FACT log.** Owns `SessionEventMap`; every entry is JSON-only (no live objects). One `session/event` emit per append, plus the `session/flush` parallel durability checkpoint. It is also the live transcript feed: a consumer that wants to render or react to what happened subscribes here, so live rendering and `session/load` replay share one path.
|
||||
- **`agent/*` — the LIVE runtime surface.** Always carries the live `Agent`. Two shapes: INTERCEPTION waterfalls (`agent/request`, `agent/step-result`, `agent/turn-continuation`) that mutate or veto, and TRANSIENT emits (`agent/status`, `agent/stream-chunk`, `agent/error`, `agent/created`/`agent/disposed`, `agent/queued`, `agent/steering`, and the turn boundaries) that notify with the `Agent` in hand.
|
||||
- **`agent/*` — the LIVE runtime surface.** Always carries the live `Agent`. Two shapes: INTERCEPTION waterfalls (`agent/request`, `agent/step-result`, `agent/turn-continuation`) that mutate or veto, and TRANSIENT emits (`agent/status`, `agent/stream-chunk`, `agent/error`, `agent/created`/`agent/disposed`, `agent/queued`, `agent/steering`) that notify with the `Agent` in hand. Turn and step BOUNDARIES are NOT here — they are durable session events read off `session/event`.
|
||||
- **`tools/*` — the tool registry + execution seam.**
|
||||
|
||||
**The boundary rule:** a durable, replayable fact is a `SessionEvent`; a live interception or a transient/live-object signal is an `agent`/`tools` Cordis event. A datum that is BOTH — a turn or step boundary — lives in the session log, and is mirrored as an `agent/*` emit ONLY where a live consumer provably needs the `Agent` handle at that instant.
|
||||
**The boundary rule:** a durable, replayable fact is a `SessionEvent`; a live interception or a transient/live-object signal is an `agent`/`tools` Cordis event. A turn or step boundary is a durable fact, so it lives in the session log and is read off the `session/event` feed — it is NOT mirrored as an `agent/*` emit.
|
||||
|
||||
**Applying the rule to the boundary twins (prune case-by-case):**
|
||||
|
||||
- `agent/turn-start` — **KEPT.** The stdio UI (`dsh-ui-stdio`) labels turn output by `agent.id`, which the `turn/start` session event does not carry. A genuine live-object need.
|
||||
- `agent/turn-end` — **KEPT.** The stdio UI listens to print the next-prompt glyph. (Note: the ACP bridge does NOT settle on this event — it settles from `session/event` `turn/end` plus `agent/status`; the surviving justification is the stdio UI alone.)
|
||||
- `agent/step-start`, `agent/step-end` — **REMOVED.** No production consumer needs the live `Agent` at a step boundary; a consumer that wants per-step boundaries reads the durable `step/start`/`step/end` session events. Removing the two emits also simplifies the loop's `closeStep` (one append, no paired emit).
|
||||
**Applying the rule to the boundary twins:** all four boundary mirrors — `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end` — are **REMOVED**. No production consumer needs the live `Agent` at a boundary: the ACP bridge settles from `session/event` `turn/end` plus `agent/status`, and the only turn-mirror consumer (`dsh-ui-stdio`, a disposable test REPL) was migrated to render boundaries from `session/event`, recovering the short agent label from an `agent/created`→id map. The step mirrors were removed first (they had no consumer at all); the turn mirrors followed once ui-stdio was migrated — see [the remove-boundary-mirror-events RFC](../simplification/2026-06-20-remove-agent-boundary-mirror-events.md), which owns that decision. Removing the emits also simplifies the loop's `closeStep`/`closeTurn` (one append each, no paired emit).
|
||||
|
||||
## Consequences
|
||||
|
||||
- The loop no longer emits `agent/step-start`/`agent/step-end`; `closeStep` appends `step/end` only, and a throwing `step/end` session-event listener is the surviving step-boundary-listener failure path (contained by `closeStep` → `failTurn`, the turn closes balanced).
|
||||
- Tests that observed step boundaries via the removed emits now observe the durable `step/start`/`step/end` session events — the behavior they pin (boundary ordering, step counting, a throwing boundary listener failing the turn balanced) is unchanged; only the feed they read moved to the canonical one. Per [AGENTS.md "tests document behavior, not golden truth"](../../../../AGENTS.md), the behavior and its test moved together.
|
||||
- The loop no longer emits any boundary mirror; `closeStep` appends `step/end` only and `closeTurn` appends `turn/end` only. A throwing `step/end`/`turn/end` session-event listener is the surviving boundary-listener failure path (contained inside `closeStep`/`closeTurn` — `Session.append` pushes the event before notifying listeners, so the boundary is durable and the turn closes balanced regardless).
|
||||
- Tests that observed boundaries via the removed emits now observe the durable `turn/start`/`turn/end`/`step/start`/`step/end` session events — the behavior they pin (boundary ordering, step counting) is unchanged; only the feed they read moved to the canonical one. The tests that exercised a *throwing turn-boundary emit listener* were deleted, because that code path no longer exists (there is no emit to throw from). Per [AGENTS.md "tests document behavior, not golden truth"](../../../../AGENTS.md), the behavior and its test moved (or died) together.
|
||||
- The loop marks the step open (`stepOpen = true`) BEFORE appending `step/start`, because `Session.append` pushes the event to the log before notifying `session/event` listeners (validation throws happen earlier, before the push — see [the session append contract](../../../core-data-structures/session.md)). So a throwing `step/start` session-event listener runs with the step already open and the event already in the log: the loop's outer catch then calls `closeStep()`, which appends the balancing `step/end`, and the turn closes balanced with an error (`turn/start → step/start → step/end → turn/end` — verified by the invariants oracle in the regression test). Closing the open step is owed precisely because the marker is set first.
|
||||
- This is a partial, conservative realization of the broader [proposed simplification "Stop mirroring durable boundaries as agent events"](../../proposed/simplification/2026-06-20-remove-agent-boundary-mirror-events.md): that RFC proposes removing ALL boundary mirrors (including the turn boundaries and `agent/steering`) and migrating the stdio UI's turn rendering onto `session/event`. This RFC removes only the two step mirrors that have no live consumer; the turn mirrors stay until the stdio UI is migrated. The proposed RFC remains the home for finishing that migration.
|
||||
- The cordis catalog (`docs/cordis-catalog/events-and-services.md`) is regenerated to drop the two events.
|
||||
- The full realization of this is [the simplification RFC "Stop mirroring durable boundaries as agent events"](../simplification/2026-06-20-remove-agent-boundary-mirror-events.md): all four boundary mirrors are removed and every consumer reads boundaries off `session/event`. `agent/steering` (a live control signal, not a boundary mirror) is retained; see that RFC's scope section.
|
||||
- The cordis catalog (`docs/cordis-catalog/events-and-services.md`) is regenerated to drop the mirror events.
|
||||
|
||||
@@ -0,0 +1,120 @@
|
||||
# RFC: Compaction as a capability seam (abstract contract + basic backend)
|
||||
|
||||
Status: implemented (2026-06-18; retention/seam reform 2026-06-26)
|
||||
|
||||
## Context
|
||||
|
||||
A long-running agent conversation grows without bound. As the event log accumulates turns, the derived message history eventually approaches the model's context window — the model then truncates mid-response (`max-tokens`) or degrades. **Compaction** is the mitigation: replace a run of older history with a concise summary, keeping recent context intact.
|
||||
|
||||
The [session surface](../../implemented/architecture/2026-06-18-session-surface.md) was built as the foundation for exactly this — a linked list over the event log with a `surfaceOp: { op: 'replace', start, end }` operation purpose-built to shadow a range of nodes and insert a replacement, with `sourceEventSeqs` recording provenance so the decision replays deterministically. What remained was the plugin that *decides what to compact and produces the summary*.
|
||||
|
||||
Two forces shape the design. First, compaction is **swappable**: token counting can be a char/4 heuristic or a real tokenizer, and summarization can be a model call, a template, or a remote service — these vary independently of *when* and *which range* to compact. Second, a later commit (`ce43c25`) closed `SurfaceEventType` to five event types (`user/message`, `assistant/message`, `tool/result`, `context/message`, `steering/message`); only those may carry `surfaceOp`. A bespoke `compaction/*` event therefore **cannot** itself appear on the surface — the compiler rejects `surfaceOp` on it and the invariants plugin rejects it at runtime.
|
||||
|
||||
## Decision
|
||||
|
||||
### Compaction is a capability seam, split interface / implementation
|
||||
|
||||
Per the [capability-seams RFC](../../implemented/architecture/2026-06-13-capability-seams.md), compaction ships as separate packages so the contract, the algorithm, and (later) the consumer surface evolve independently:
|
||||
|
||||
1. **Interface** — `@deepseek-ai/dsh-compact`: an abstract `CompactService` owning the `ctx.compact` key, the `CompactionResult` vocabulary, and the `compact/*` session events. It declares `compactIfNeeded()` and `compactRegion()` as **abstract** — the contract states *what* compaction does, not *how*.
|
||||
2. **Implementation** — `@deepseek-ai/dsh-compact-basic`: a concrete `BasicCompactService` that owns the entire algorithm — token estimation (char/4 + per-block overhead), the tail→head retention walk, summarization via `ctx.llm.stream()`, the surface replacement, the lock, and the `agent/pre-step` auto-compaction listener. A tokenizer-based or template-based backend is a sibling package (or a subclass overriding the two protected estimation/summarization hooks).
|
||||
3. **Consumer** — deferred. A `/compact` tool and slash command will `inject: ['compact']` and call the contract; they are intentionally out of scope here so the seam settles first.
|
||||
|
||||
### The contract depends on `dsh-session` and `dsh-llm` — a deliberate deviation
|
||||
|
||||
The capability-seams RFC states the interface package "depends only on cordis" (true of `dsh-bash`, whose vocabulary is self-contained). Compaction **cannot** honor that: its verbs are defined *over* a `Session` (`compactRegion(session, start, end)`) and its output *is* the content vocabulary (`CompactionResult.summary: ContentBlock[]`). There is no way to express the contract without naming `Session`/`SessionEvent` (from `dsh-session`) and `ContentBlock` (from `dsh-llm`).
|
||||
|
||||
This is not a coupling smell — it is the contract's domain. The "only cordis" guidance was always shorthand for "the interface depends only on what the contract genuinely names, and never on an implementation." `dsh-session` and `dsh-llm` are themselves interface/vocabulary packages, not implementations; `dsh-compact` still imports no backend. The seam's real invariant — *consumers and implementations evolve independently behind an abstract service* — holds intact.
|
||||
|
||||
### Abstract `compactIfNeeded` / `compactRegion`, algorithm in the backend
|
||||
|
||||
An earlier draft put the full algorithm (the retention walk, token-summing, text extraction) as concrete methods on the interface, with only `estimateContentTokens()` and `summarize()` abstract. That recouples the contract to one strategy: a backend that wants a different retention policy or a different event-sequencing would have to fight inherited concrete code. Making both core methods abstract puts every *how* decision in the backend, where it belongs, and keeps the interface a pure statement of *what*. The backend remains internally factored — `estimateContentTokens()` and `summarize()` are `protected` hooks a sub-backend can override without reimplementing the walk — but that factoring is the backend's private concern, not the contract's.
|
||||
|
||||
`compactIfNeeded(agent, turn, step, fullSystemPrompt, signal)` takes **required** parameters (not the original all-optional shape). The auto-compaction seam (below) always supplies the agent, lifecycle context, assembled system prompt (counted toward the estimate), and the turn's abort signal, so optionality would only invite a hidden default at the seam. The session being compacted comes from the agent context. `compactRegion(session, start, end, agent, turn, step, signal?)` keeps an optional signal (a manual caller may omit it). Passing lifecycle context rather than a concrete model keeps router agents honest: the backend's summarization request can run through `agent/request`, where model-routing plugins already choose the actual model.
|
||||
|
||||
### Auto-compaction runs on `agent/pre-step`, a dedicated surface-mutation seam
|
||||
|
||||
Compaction is a **surface mutation**, not a request transform — and that distinction is the seam it belongs on. The loop's request lifecycle, per step, is: assemble the system prompt → open the step → derive the message history from the surface → run the `agent/request` waterfall → call the model. An earlier cut wedged compaction into the `agent/request` waterfall, which forced two problems: (1) the loop had already derived `messages` from the *stale* surface, so the listener had to mutate the surface and then *re-derive* and overwrite `request.messages` — a double-derive whose only purpose was to undo the premature first derive; and (2) `agent/request` also carries downstream-injected context a listener might have added to `request.messages`, which compaction cannot act on (it can only compact the surface), inviting the confusion of measuring tokens compaction can't shed.
|
||||
|
||||
The fix is a dedicated loop seam, **`agent/pre-step`** (`@mode serial`), fired by the loop *after* system assembly and *before* the step opens (`step/start`):
|
||||
|
||||
```
|
||||
assembly = ctx.systemPrompt.assemble()
|
||||
await ctx.serial('agent/pre-step', agent, turn, step, system, signal) ⟵ compaction mutates the surface here
|
||||
session('step/start') ⟵ the step opens AFTER the seam
|
||||
messages = session.deriveMessages() ⟵ single derive, reflects the compaction
|
||||
request = waterfall agent/request ⟵ pure request transform (hooks, model switch)
|
||||
```
|
||||
|
||||
This makes the layering correct *by construction*: compaction mutates the surface, the loop derives **once** from the result (no double-derive), and at `pre-step` the assembled `messages` do not yet exist — so a listener structurally *cannot* see or be expected to act on downstream-injected context. `agent/request` reverts to a pure request transformer. Firing the seam **before** `step/start` (not inside the open step) is load-bearing for crash-safety: compaction's log-only `compact/*` records and its replacement node land *outside* any step, so the honest log structure a crash leaves (a dangling `compact/start` sitting before the synthetic `turn/end` that turn-repair appends) holds without a half-open step to reconcile. The seam is `serial` (awaited, in registration order), not `parallel`: a listener mutates the surface as a side effect — there is nothing to transform or return — and serial isolates listeners from each other so two surface-mutating listeners can never interleave their `session.append`s. Cordis `serial` does bail early if a listener returns a bail value, so `agent/pre-step` listeners are typed/documented to return `void` and must not use that bail channel as a semantic veto surface.
|
||||
|
||||
This **amends** the original RFC's claim of "NO changes to `dsh-agent-loop`; compaction is a pure plugin." That claim was load-bearing for a wrong design — reusing `agent/request` was the mistake. Per the pre-release "foundation over blast radius" stance, adding the correct seam (one event declaration in `dsh-agent`, one awaited emit in the loop) beats preserving a no-change boast that locked in the double-derive.
|
||||
|
||||
### Retention is turn-agnostic; tool-pairing balance is the only structural guard
|
||||
|
||||
Auto-compaction fires before **every** step, not once per turn. This is **load-bearing for runaway-turn survival**: a tool-heavy ReAct turn appends an `assistant/message` + a `tool/result` per step, so the surface grows *within* a turn. A single turn can grow past the window on its own (a "runaway turn") — and the only moment to rescue it before the next model call overflows is the next step's `pre-step` checkpoint. Gating compaction to a turn's first step (or, worse, retaining the whole in-flight turn verbatim) re-opens exactly the hole compaction exists to close: the harness would die when compaction is most needed.
|
||||
|
||||
So retention does **not** protect the in-flight turn, and turn boundaries play no role in it. `compactIfNeeded` walks the surface nodes tail→head, summing per-node token estimates, and retains the smallest tail-run of **whole units** whose total reaches `retainTokens`; everything older is compacted (head-anchored — see below). A *unit* is either a whole closed step (its `assistant/message` plus its `tool/result`s) or a single no-step node (a pre-step `user/message`, inter-step `steering/message`, or injection `context/message`). The walk rounds toward retaining *more*: when the raw token cutoff lands mid-step, it extends the retained side head-ward until the cut before the retained node is **tool-pairing balanced**. The single structural guard is therefore **tool-pairing balance** — a region's edges are balanced cuts on the *surface* (no unanswered `tool-call` crosses either edge), so a compacted region never splits a step's tool-calls from their `tool/result`s (which would produce a transcript every provider rejects). The check is decided over the surface linked list, **not** the log's `step/*` markers: a compaction lands a replacement node at a high log seq whose surface position is the head, so a log-position scan mis-reads its neighbours — `dsh-session` exports `isToolPairingBalanced(nodes, events, beforeSeq)` for the surface-anchored check. `compactRegion` enforces it strictly, throwing on a boundary that would split a step.
|
||||
|
||||
A runaway turn thus compacts exactly like any other history: its early *closed* steps get summarized while its recent steps stay verbatim. When the only compactable content left is an un-splittable open tail step (its tool-calls have no results yet), compaction declines (`null`) and retries once that step closes.
|
||||
|
||||
**Single-unit overflow is out of scope, by design.** If a single retained unit — one closed step, or a large free node such as a pasted `user/message` — *alone* exceeds the budget, compaction cannot help and the next model call may go out over-budget. Bounding an individual unit's size is a separate concern (output truncation), handled elsewhere; compaction makes no promise about it, and the harness without such a mechanism can still break on a single oversized unit. This is named honestly rather than papered over.
|
||||
|
||||
### Head-anchoring: one auto checkpoint, always at the head
|
||||
|
||||
`compactIfNeeded` always anchors the compacted range at the surface **head** (`nodes[0]`). After a first compaction lands a summary node at the head, the *second* compaction's range starts at that summary node and re-summarizes it together with the steps accumulated since — so the surface holds **at most one** auto-generated checkpoint, always at the head, re-consolidated each cycle (the backend's checkpoint-merge prompt makes this a cheap incremental merge — see below). This is *why* `CompactionResult.shadowedRange` is a **surface-position span, not a numeric seq interval**: after a replace lands a fresh high-seq summary node at an older range's position, `start` can be numerically **greater** than `end`. The range is resolved positionally (index into the ordered node list and slice), and `shadowedSeqs` is the authoritative set in surface order. (Manual `compactRegion` may target any aligned mid-range and so *can* leave several checkpoints; the checkpoint framing does not claim everything after it is recent.)
|
||||
|
||||
### Approximate convergence invariant
|
||||
|
||||
`resolveConfig` validates numeric knobs but does NOT reject based on a pretend summary-length invariant. Convergence is dynamic: provider output caps can be spent on hidden or surfaced reasoning tokens, and the model may emit a summary of unpredictable size. `maxTokens` is only the provider-side generation cap for the summarization call; reasoning blocks are stripped before the checkpoint is stored. If a compacted surface is still over threshold, `compactIfNeeded()` re-compacts the head checkpoint up to `compactionRetries` extra times, but each committed summary must be smaller than the content it shadows. The sole residual is the single-unit-overflow case above (a backward-rounded oversized step can push the retained tail over budget) — which is exactly the out-of-scope concern, not a thrash bug.
|
||||
|
||||
### Surface replacement: `compact/*` events are log-only; one `user/message` carries the summary
|
||||
|
||||
Because `SurfaceEventType` is closed, the summary cannot ride on a `compact/*` event. The backend instead appends a **single `user/message`** with `surfaceOp: { op: 'replace', start, end }` whose `content` is the (framed) summary and whose `sourceEventSeqs` covers the shadowed nodes *and* the bookkeeping events. The `compact/*` events are pure log records (lock + provenance). The surface mutation sits **inside** the lock — `compact/end` is the last event appended:
|
||||
|
||||
```
|
||||
compact/start → log-only. Acquires the lock.
|
||||
[summarize older range via the backend]
|
||||
compact/summary → log-only. Provenance: raw summary, range, shadowed seqs, token count.
|
||||
user/message → surfaceOp { op:'replace', start, end }. THE surface mutation (framed summary).
|
||||
deriveMessages() renders it as a user-role message.
|
||||
compact/end → log-only. Releases the lock (carries `error` on a recoverable failure).
|
||||
```
|
||||
|
||||
`deriveMessages()` then yields `[summary_as_user_message, ...retained_nodes]`. Reusing `user/message` is honest rather than a workaround: a summary genuinely *is* user-role context.
|
||||
|
||||
### Checkpoint framing + incremental merge (backend-private)
|
||||
|
||||
The landed `user/message` is not the raw summary: the backend wraps it in a checkpoint preamble (so a resuming model reads it as established background, not a fresh request) and `<compacted-summary>…</compacted-summary>` tags. The tags make a prior checkpoint detectable on the next cycle, and the summarization prompt then instructs the model to *merge it in place* (preserve still-true facts, drop stale) rather than re-summarize verbatim — a cheap incremental merge that needs no extra log/event machinery. The raw, unframed summary stays on the `compact/summary` provenance event. This framing is entirely a **backend HOW decision** — the contract only promises "a single replace `user/message` carries the (possibly framed) summary; the raw summary lives on `compact/summary`." A template or remote backend may frame differently or not at all.
|
||||
|
||||
### Blocking via a log-recorded lock, plus a crash/recoverable failure taxonomy
|
||||
|
||||
The `compact/start … compact/end` bracket is justified, in order of what now does the work:
|
||||
|
||||
1. **Crash-detectable orphan + provenance** (primary). Summarization is a slow model call persisted *after* `compact/start`. A crash mid-summarization leaves a `compact/start` with no matching `compact/end` — a detectable orphan. Releasing the lock last (rather than first) converts the crash window from *silent corruption* into that detectable orphan.
|
||||
2. **Prevents concurrent compaction.** `compactRegion` refuses to start if the current turn holds an unmatched `compact/start`. (The loop is single-threaded across the awaited `pre-step`, so this is also a re-entry tripwire — a thrown "already in progress" signals a real bug.)
|
||||
|
||||
Two failure paths, both documented:
|
||||
|
||||
- **Crash** (the loop dies mid-summarization): a dangling `compact/start`, no closer. Because `compact/*` are **log-only**, the orphan is **inert** — the surface replacement never landed, so the full, uncompacted history derives correctly. Generic turn-repair (`interruptedTurnClosers`) closes the turn with a synthetic `turn/end`; the orphan sits *before* that `turn/end`, so the turn-scoped in-progress check never sees it and a crash can't wedge future compaction. Compaction simply re-attempts at the next `pre-step`.
|
||||
- **Recoverable** (summarization throws but the loop survives): the backend appends `compact/end` with its **`error`** field set, leaving the surface untouched, and the model call proceeds with full history.
|
||||
|
||||
`compact/end` keeps its `error?` field (mirroring `tool/result`'s self-contained error — one event tells success from failure without correlating a sibling). There is no separate `compact/error` event.
|
||||
|
||||
**Core session repair stays compaction-agnostic — deliberately.** `interruptedTurnClosers` is never taught about `compact/*`. Teaching it would force every future `xxx/start … xxx/end` plugin pair to patch a core module — exactly the coupling the capability-seam architecture exists to avoid. Because the log-only orphan is inert, no special repair is needed: generic turn-repair plus the inertness of an un-landed surface mutation is sufficient.
|
||||
|
||||
## Consequences
|
||||
|
||||
- **New packages**: `packages/compact/compact` (interface) and a sibling `compact-basic` (backend) under `packages/compact/`, wired into the root tsconfigs. The consumer tier is deferred.
|
||||
- **New loop seam**: `agent/pre-step` (`@mode serial`) declared in `dsh-agent` and emitted by `dsh-agent-loop` after system assembly and before `step/start`. This is a documented change to the loop — `docs/architecture.md` records it and the generated cordis catalog carries its signature.
|
||||
- **`SessionEventMap`** gains `compact/start` / `compact/summary` / `compact/end` by declaration merging (merge-extensible); `SurfaceEventType` is **not** touched. These are session events, not cordis `Events`, so the event-taxonomy gate needs no entry.
|
||||
- **`dsh-session`** gains the tool-pairing balance predicate (`isToolPairingBalanced`, in `tool-pairing.ts`, exported from the package index) that `compactRegion`/`compactIfNeeded` use to keep a collapsed region from splitting a step's tool-call/result pair. The surface `replace` op and the surface-metadata runtime guard already existed and are reused.
|
||||
- **`dsh-invariants`** drops its `surface replace: start must be <= end` assertion: a head-anchored compaction lands a high-seq replacement node at an older range's *position*, so `start > end` numerically is normal and valid (the range is positional, validated by the surface's `indexOf` checks that remain). The turn-enclosure invariant is reused unchanged.
|
||||
- **Wiring**: `dsh-compact-basic` is loaded in `examples/coding-agent`'s `cordis.yml`, so the seam ships in the real demo (it was previously loaded nowhere).
|
||||
|
||||
## Testing
|
||||
|
||||
- **Unit** (`dsh-compact-basic`): the whole-unit retention walk, the convergence-invariant throw, both failure paths (`compact/end` with/without `error`), head-anchoring producing a non-monotonic `shadowedRange`, decline-on-open-tail, crash-orphan inertness, and the **runaway-turn regression** — a single oversized open turn compacts its early closed steps (proven to fail on the layer-2 protection it replaced). Driven through the real `dsh-invariants` plugin and the real Loader/inject path.
|
||||
- **Loop** (`dsh-agent-loop`): `agent/pre-step` fires once per step, after `turn/start` and before `step/start`, awaited; a surface mutation in a `pre-step` listener lands outside the step and is reflected in the single derived request.
|
||||
- **With-key e2e** (`examples/coding-agent`): a real model + real bash session with a lowered `contextWindow`/`retainTokens` triggers compaction mid-session; the test verifies the WORLD (a `compact/start…end` pair landed, the surface shrank, the agent still completed the task after compaction). This is compaction's first real-world exercise and the runaway-survival net.
|
||||
- **Snapshot (deferred, named gap)**: a full-transcript snapshot of a runaway-turn compaction is NOT yet possible — `dsh-llm-replay` derives one model call per `(turn, step)` from `assistant/chunk` events, but the summarization call records no `assistant/chunk`s and carries no `sessionId` (it binds to the anonymous cursor and claims a non-existent extra script). Covering it needs net-new replay infrastructure (record/replay an interleaved summarization call) and is scheduled as a follow-up rather than discovered mid-build.
|
||||
@@ -20,7 +20,7 @@ Pure generation is correct here because the codebase is disciplined enough that
|
||||
|
||||
Specific choices:
|
||||
|
||||
- **`@mode` tag, cross-checked.** Each harness event's JSDoc carries an explicit `@mode emit|waterfall|parallel` tag; the generator hard-errors on a missing tag. Where the signature shape is conclusive — a trailing `next: () => …` parameter is structurally a waterfall — it asserts the tag agrees and hard-errors on a contradiction. The emit-vs-parallel distinction is not structurally visible (`session/flush` returns `Promise<void> | void` with no `next`), so it is trusted from the tag. The authoring rule lives in [AGENTS.md](../../../../AGENTS.md).
|
||||
- **`@mode` tag, cross-checked.** Each harness event's JSDoc carries an explicit `@mode emit|waterfall|parallel|serial` tag; the generator hard-errors on a missing tag. Where the signature shape is conclusive — a trailing `next: () => …` parameter is structurally a waterfall — it asserts the tag agrees and hard-errors on a contradiction. The emit/parallel/serial distinction is not structurally visible (`session/flush` returns `Promise<void> | void` with no `next`, as does the ordered `agent/pre-step` checkpoint), so it is trusted from the tag. The authoring rule lives in [AGENTS.md](../../../../AGENTS.md).
|
||||
- **Tiered scope.** The harness tier (the 8 `@deepseek-ai/dsh-*` services + their events) is rendered in full from source. The inherited tier (cordis-core `ctx.on/emit/effect/provide/…` + the `internal/*` events + loader/hmr/timer) is pinned vendor source a plugin also sees; it is rendered tersely (name + one-line + source pointer) from a curated table in the generator, NOT walked from the vendor AST — the cordis-core `Context` mixes true ctx members with non-service fields (`root`, `baseUrl`, `logger`), and the vendor surface changes only on a deliberate vendor sync.
|
||||
- **Cross-links to the data-structure catalog.** A type name in a signature (`GenerateOptions`, `StreamChunk`, `ToolDefinition`, …) links to the core-data-structures page that documents it. The map is a small hand-curated const in the generator — NOT `type-equiv.manifest.json`, which documents the `…Map` symbols while signatures reference the derived union names, and lists a few symbols on two pages.
|
||||
- **A dedicated fence.** Signature blocks use a ` ```ts cordis-catalog ` info string that `doc-typecheck` recognizes and skips (a bare signature fragment is not standalone-compilable), excluded from the opt-out ratio — the same treatment `type-equiv` blocks get.
|
||||
|
||||
@@ -0,0 +1,37 @@
|
||||
# RFC: Stop mirroring durable boundaries as agent events
|
||||
|
||||
Status: implemented (accepted 2026-07-01)
|
||||
|
||||
<!-- Shipped in AMENDED, narrowed form: the four turn/step BOUNDARY mirrors are
|
||||
removed; `agent/steering` and `agent/stream-chunk` are RETAINED (they are
|
||||
not durable-boundary mirrors — see "Scope: what is and isn't removed"). The
|
||||
original proposal bundled `agent/steering` into the removal; validating
|
||||
against the code showed it is a distinct live-only signal, so it stayed. -->
|
||||
|
||||
## Problem
|
||||
|
||||
The loop records the canonical transcript in `SessionEvent` and also emitted a parallel set of live `agent/*` boundary mirror events: `agent/turn-start`, `agent/turn-end`, `agent/step-start`, and `agent/step-end`. The mirrors made consumers choose between two sources of truth for the SAME durable fact. ACP already chose the session log for the editor-facing transcript because a throwing peer listener can prevent later `agent/*` listeners from observing a boundary, while the session event was already appended. The stdio UI was the only production consumer that still rendered turn boundaries from the mirror events; it already rendered tool calls and results from `session/event`.
|
||||
|
||||
This duplication is not free. Every lifecycle change had to update the session event, the mirror event, docs, invariants, tests, and snapshot expectations. The duplicate boundary events also made failure ordering subtle: a turn can be durably closed before a live `agent/turn-end` listener runs, so a post-boundary listener failure has no valid in-log position left and must be reported out of band.
|
||||
|
||||
## Decision
|
||||
|
||||
Make `session/event` the single live boundary/transcript stream. Consumers that render turns, tool calls, tool results, assistant messages, and durable boundaries subscribe to `session/event` and derive their UI from the same event vocabulary persistence uses.
|
||||
|
||||
The four durable-boundary mirrors — `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end` — are removed from the agent event taxonomy. A UI that wants the agent handle (or its short id) at a boundary keeps a small map from session id to agent id built from `agent/created`/`agent/disposed`; `dsh-ui-stdio` does exactly this to label its `[<agent> turn N]` header, since the `turn/start` session event carries only the turn number. The canonical record remains the event-sourced session log.
|
||||
|
||||
The step mirrors (which had no consumer at all) were removed first, in [the event-domain-semantics RFC](../architecture/2026-06-30-event-domain-semantics.md); that RFC KEPT the turn mirrors on the stated justification that the stdio UI needed the `Agent` handle at the turn boundary. This RFC finishes the job: `dsh-ui-stdio` is a disposable test REPL whose rendering can change freely, so "ui-stdio needs it" is not a reason to keep a mirror — it was migrated to `session/event` + the id map, and the turn mirrors were removed too.
|
||||
|
||||
## Scope: what is and isn't removed
|
||||
|
||||
Removed (durable-boundary mirrors — the session log is authoritative for each): `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end`.
|
||||
|
||||
RETAINED — NOT durable-boundary mirrors, so out of scope for this decision:
|
||||
|
||||
- `agent/steering` — a live control signal, not a boundary. (The original proposal bundled it into the removal; validating against the code, it is not a duplicate of a durable boundary, so removing it here would have been scope creep. Its fate is a separate future decision.)
|
||||
- `agent/stream-chunk` — the live token stream. `assistant/chunk` persistence remains load-bearing, so the chunk stream could later be evaluated as a mirror, but that is a separate decision.
|
||||
- `agent/created`, `agent/disposed`, `agent/status`, `agent/error`, `agent/queued` — lifecycle/control events that are not transcript data. `agent/queued` in particular is an inbox acknowledgement that fires before any durable event exists (cancelled queued work may never enter the log), so it is deliberately live-only.
|
||||
|
||||
## What we give up
|
||||
|
||||
A plugin can no longer observe turn/step boundaries from a convenient `Agent`-first event. It must either subscribe to `session/event` or maintain a session-to-agent association. That is an acceptable trade: boundary consumers should not depend on a second event feed that can drift from the durable log.
|
||||
@@ -27,7 +27,7 @@ The mapping between ACP and existing harness seams — each row names the seam a
|
||||
| `session/new {cwd, mcpServers, additionalDirectories}` → `{sessionId}` | the `dsh-agent` create factory (see Dependency note + Plan) | the seam must accept `{ sessionId, meta }` so the ACP-generated `sessionId` becomes the live/persisted session id and the validated `cwd` is attached as the `SessionHeader` (today `AgentLoop.create(id)` hardcodes `${id}-session` and takes no metadata); reject a 2nd session (single-session MVP, see [ACP multi-session](2026-06-14-acp-multi-session.md)); `cwd` validated (require absolute) — any absolute cwd is honored: it becomes the session's `SessionHeader.cwd` and the default bash workdir (per-session cwd, see § Deferred → RESOLVED), so the server need not launch in the workspace; non-empty `mcpServers` and `additionalDirectories` are rejected for the MVP because silently ignoring requested servers/roots would desync the client's tool and filesystem-scope UI |
|
||||
| `session/load {sessionId, cwd, mcpServers, additionalDirectories}` | the `dsh-agent` resume factory ([session persistence](../../implemented/architecture/2026-06-14-session-persistence.md) + Dependency note) | load `{ meta, events }`, seed the session, re-derive history via `deriveMessages()`, replay prior turns to the client as `session/update` per the ACP load contract; `mcpServers` and `additionalDirectories` rejected as in `session/new` |
|
||||
| `session/prompt {prompt}` | `agent.send()` (idle) | text blocks → `TextBlock`; reject image/audio per advertised capabilities; one in-flight prompt per session |
|
||||
| resolve `session/prompt` → `{stopReason}` | `agent/turn-end` (extended, see Plan) | map the harness kebab `TurnEndReason` to the ACP snake_case `StopReason` wire enum: `completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`(cancel)→`cancelled`, plus `refusal`/`max_turn_requests` when applicable; honor the batch-into-one-turn and send-not-synchronously-running settle semantics |
|
||||
| resolve `session/prompt` → `{stopReason}` | the `turn/end` `session/event` (its `reason`) | map the harness kebab `TurnEndReason` to the ACP snake_case `StopReason` wire enum: `completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`(cancel)→`cancelled`, plus `refusal`/`max_turn_requests` when applicable; honor the batch-into-one-turn and send-not-synchronously-running settle semantics |
|
||||
| `session/update: agent_message_chunk` | `agent/stream-chunk` `text-delta` only | do NOT also emit on `block-end(TextBlock)` — it carries the fully-assembled block and would duplicate the streamed text |
|
||||
| `session/update: agent_thought_chunk` | `agent/stream-chunk` `reasoning-delta` | |
|
||||
| `session/update: tool_call` (pending→in_progress) | `session/event` `tool/call` | demux via a Session→sessionId map; `kind` inferred from the tool name |
|
||||
@@ -46,7 +46,7 @@ Lifecycle and disposal: the connection, listeners, and in-flight permission prom
|
||||
1. Package scaffold `packages/ui/acp/` per [the cookbook](../../../cookbook/adding-a-package.md); add `@agentclientprotocol/sdk` and `zod`. Add the abstract create/resume factory to `dsh-agent` (the interface) so the bridge can `inject: ['agents', 'sessions', 'tools', 'sessionPersistence']` without depending on the concrete loop; `sessionPersistence` is required because `session/load` advertises `loadSession: true`. (Fallback only if the factory is judged not worth it: inject `agentLoop` directly and record the architecture-rule exception in `docs/architecture.md`.)
|
||||
2. Connection plus `initialize`/`session/new`: wire `AgentSideConnection` to stdin/stdout; protocolVersion negotiation; the single-session guard; create the live session through the new `{ sessionId, meta }` factory seam (so the ACP `sessionId` and validated `cwd` become the session's id and header); the `sessionId↔agent` and `Session↔sessionId` maps.
|
||||
3. Internal edit — turn-end reason fidelity (sanctioned: edit internals to fit ACP). Extend `TurnEndReasonMap` in the proper places: (a) declaration-merge a `max-tokens` variant in the owning package (`packages/core/session/src/types.ts`, alongside `completed|aborted|error|disposed`) — add `max-tokens` because `FinishReasonMap` produces it (DeepSeek maps `length` → `max-tokens`); do not add `refusal`, since no current adapter produces it (unknown DeepSeek finish reasons collapse to `error`), but leave a comment in `TurnEndReasonMap` noting `refusal` should be added when an adapter first emits it (`FinishReasonMap` is merge-extensible); (b) make `agent-loop`'s `loop.ts` populate the reason from the model `finish` chunk — `assembler.finish` lives inside `runStep`, so `runStep` must return it up to `runTurn`, and the rule is "the last step's finish reason wins, but any `max-tokens` in the turn surfaces as `max-tokens`"; (c) no consumer exhaustively switches over `TurnEndReason` today (the invariants plugin switches on `SessionEventType`, and `deriveMessages` ignores `turn/end`), so adding `max-tokens` is a non-breaking extension — but recheck before landing; (d) update [docs/architecture.md](../../../architecture.md) (the CI-verified loop-lifecycle/event-taxonomy doc) and the affected package READMEs/JSDoc (`dsh-session`, `dsh-agent`, `dsh-agent-loop`) per the repo doc-sync policy. This replaces a fragile "observe the finish chunk in the bridge" hack with a real, documented contract.
|
||||
4. Prompt-turn streaming plus load: translate `agent/stream-chunk` and `session/event` into `session/update`; resolve `session/prompt` on settle, mapping the harness `TurnEndReason` to the ACP `StopReason` wire enum (`completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`→`cancelled`) — a small total function with a test asserting the exact wire strings, since the SDK rejects an unknown `stopReason`. Concrete correlation, since the loop batches queued messages into one turn and `send()` does not synchronously flip to running: install listeners before `send()`; gate on an observed `agent/turn-start` (confirms work was accepted) then resolve on the next `agent/turn-end`; reject an empty/whitespace prompt up front rather than calling `send()` (no turn would ever start, so the RPC would hang). Implement `session/load` on the session-persistence resume seam.
|
||||
4. Prompt-turn streaming plus load: translate `agent/stream-chunk` and `session/event` into `session/update`; resolve `session/prompt` on settle, mapping the harness `TurnEndReason` to the ACP `StopReason` wire enum (`completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`→`cancelled`) — a small total function with a test asserting the exact wire strings, since the SDK rejects an unknown `stopReason`. Concrete correlation, since the loop batches queued messages into one turn and `send()` does not synchronously flip to running: install the `session/event` listener before `send()`; capture the prompt's owning turn from its `turn/start` record, then resolve on that turn's `turn/end` (with `agent/status` idle/disposed as a fallback); reject an empty/whitespace prompt up front rather than calling `send()` (no turn would ever start, so the RPC would hang). Implement `session/load` on the session-persistence resume seam.
|
||||
5. Permission gate: a single `tools/execute` listener registered with `prepend: true`, owning a `WeakMap<Agent, sessionId>` of bridge-created agents; no-op (`next()`) for unowned/no-agent calls; for owned calls → `session/request_permission` → allow (`next()`) / veto; settle the stored resolver exactly once on outcome, cancel, or connection close.
|
||||
6. Example wiring (extract a shared base). `@cordisjs/plugin-include` is itself a plugin entry that resets `ctx.baseUrl` and loads a path, so a child `cordis.yml` can nest-include a shared base; the extraction is safe because every dependent plugin declares `inject` (loader groups initialize via `Promise.all`, so YAML order is NOT the dependency mechanism — never rely on it). Extract the provider/tool core (`llm, sessions, system-prompt, tools, agents, invariants, llm-deepseek, bash-local, tool-bash`) into `examples/base.yml`; have both `coding-agent` and a new `examples/acp-agent/` include it and add their own UI plugin plus logger. Keep `agent-loop` per-example (NOT in the base): `AgentLoop` creates its configured agents in its constructor, and the two examples disagree — `coding-agent` needs a pre-created `main` (its `stdio-chat` calls `ctx.agents.get('main')`), while `acp-agent` must pre-create none (ACP `session/new` creates agents). So `coding-agent` declares `agent-loop` with `agents: [{ id: main, … }]` and `acp-agent` with `agents: []`. `acp-agent` loads `dsh-session-persistence-jsonl` (from [session persistence](../../implemented/architecture/2026-06-14-session-persistence.md) — required for `session/load`), omits the stdout logger (see Risks), and adds `pnpm run demo:acp` plus the Zed `agent_servers` snippet.
|
||||
7. Tests (the repo cares a lot here): a property-based test for the protocol shape (precedent: [property-based testing](../../implemented/testing/2026-06-11-property-based-testing.md)) — fuzz arbitrary harness event sequences and assert ACP-stream invariants (never a `tool_call_update` before its `tool_call`; exactly one `session/prompt` resolution per prompt; monotonic, well-formed ordering; `stopReason` in the legal set); codec unit tests over an in-memory `Duplex` pair (drive `AgentSideConnection` without a subprocess; assert exact frames for `initialize`, `session/new`, a full prompt turn); the mandatory HMR-safety test (dispose the fiber; assert the connection closed, all `ctx.on` listeners gone, any in-flight `request_permission` settled); failure-path tests (connection closes mid-stream; closes with a permission pending; a notification `send()` rejects but the turn survives; `finish{kind:'error'|'aborted'}`; a `tools/execute` throw with no `tool/result`; a second `session/new` rejected; a `session/prompt` while one is in flight; an empty prompt rejected without hanging; a `session/load` re-derives identical history and replays it); and an e2e (`*.e2e.ts`, self-skips without `DEEPSEEK_API_KEY`) that boots `examples/acp-agent`, connects a `ClientSideConnection`, sends a real prompt, owns and disposes the harness in `afterEach`, and verifies the world (files on disk), not the agent's self-report.
|
||||
|
||||
@@ -1,59 +0,0 @@
|
||||
# RFC: Compaction as a capability seam (abstract contract + basic backend)
|
||||
|
||||
Status: proposed (2026-06-18)
|
||||
|
||||
## Context
|
||||
|
||||
A long-running agent conversation grows without bound. As the event log accumulates turns, the derived message history eventually approaches the model's context window — the model then truncates mid-response (`max-tokens`) or degrades. **Compaction** is the mitigation: replace a run of older history with a concise summary, keeping recent context intact.
|
||||
|
||||
The [session surface](../../implemented/architecture/2026-06-18-session-surface.md) was built as the foundation for exactly this — a linked list over the event log with a `surfaceOp: { op: 'replace', start, end }` operation purpose-built to shadow a range of nodes and insert a replacement, with `sourceEventSeqs` recording provenance so the decision replays deterministically. What remained was the plugin that *decides what to compact and produces the summary*.
|
||||
|
||||
Two forces shape the design. First, compaction is **swappable**: token counting can be a char/4 heuristic or a real tokenizer, and summarization can be a model call, a template, or a remote service — these vary independently of *when* and *which range* to compact. Second, a later commit (`ce43c25`) closed `SurfaceEventType` to five event types (`user/message`, `assistant/message`, `tool/result`, `context/message`, `steering/message`); only those may carry `surfaceOp`. A bespoke `compaction/*` event therefore **cannot** itself appear on the surface — the compiler rejects `surfaceOp` on it and the invariants plugin rejects it at runtime.
|
||||
|
||||
## Decision
|
||||
|
||||
### Compaction is a capability seam, split interface / implementation
|
||||
|
||||
Per the [capability-seams RFC](../../implemented/architecture/2026-06-13-capability-seams.md), compaction ships as separate packages so the contract, the algorithm, and (later) the consumer surface evolve independently:
|
||||
|
||||
1. **Interface** — `@deepseek-ai/dsh-compact`: an abstract `CompactService` owning the `ctx.compact` key, the `CompactionResult` vocabulary, and the `compact/*` session events. It declares `compactIfNeeded()` and `compactRegion()` as **abstract** — the contract states *what* compaction does, not *how*.
|
||||
2. **Implementation** — `@deepseek-ai/dsh-compact-basic`: a concrete `BasicCompactService` that owns the entire algorithm — token estimation (char/4 + per-block overhead), the tail→head retention walk, summarization via `ctx.llm.generate()`, the surface replacement, the lock, and the `agent/request` auto-compaction listener. A tokenizer-based or template-based backend is a sibling package (or a subclass overriding the two protected estimation/summarization hooks).
|
||||
3. **Consumer** — deferred. A `/compact` tool and slash command will `inject: ['compact']` and call the contract; they are intentionally out of scope here so the seam settles first.
|
||||
|
||||
### The contract depends on `dsh-session` and `dsh-llm` — a deliberate deviation
|
||||
|
||||
The capability-seams RFC states the interface package "depends only on cordis" (true of `dsh-bash`, whose vocabulary is self-contained). Compaction **cannot** honor that: its verbs are defined *over* a `Session` (`compactRegion(session, start, end)`) and its output *is* the content vocabulary (`CompactionResult.summary: ContentBlock[]`). There is no way to express the contract without naming `Session`/`SessionEvent` (from `dsh-session`) and `ContentBlock` (from `dsh-llm`).
|
||||
|
||||
This is not a coupling smell — it is the contract's domain. The "only cordis" guidance was always shorthand for "the interface depends only on what the contract genuinely names, and never on an implementation." `dsh-session` and `dsh-llm` are themselves interface/vocabulary packages, not implementations; `dsh-compact` still imports no backend. The seam's real invariant — *consumers and implementations evolve independently behind an abstract service* — holds intact. We record the deviation here so a future reader doesn't mistake it for an accident or "fix" it by smuggling `Session` behind an opaque handle.
|
||||
|
||||
### Abstract `compactIfNeeded` / `compactRegion`, algorithm in the backend
|
||||
|
||||
An earlier draft put the full algorithm (the retention walk, token-summing, text extraction) as concrete methods on the interface, with only `estimateContentTokens()` and `summarize()` abstract. That recouples the contract to one strategy: a backend that wants a different retention policy (e.g. turn-count instead of token-budget) or a different event-sequencing would have to fight inherited concrete code. Making both core methods abstract puts every *how* decision in the backend, where it belongs, and keeps the interface a pure statement of *what*. The backend remains internally factored — `estimateContentTokens()` and `summarize()` are `protected` hooks a sub-backend can override without reimplementing the walk — but that factoring is the backend's private concern, not the contract's.
|
||||
|
||||
### Surface replacement: `compact/*` events are log-only; one `user/message` carries the summary
|
||||
|
||||
Because `SurfaceEventType` is closed, the summary cannot ride on a `compact/*` event. The backend instead appends a **single `user/message`** with `surfaceOp: { op: 'replace', start, end }` whose `content` is the summary `ContentBlock[]` and whose `sourceEventSeqs` covers the shadowed nodes *and* the bookkeeping events. The `compact/*` events are pure log records (lock + provenance), never on the surface. The surface mutation sits **inside** the lock — `compact/end` is the last event appended:
|
||||
|
||||
```
|
||||
compact/start → log-only. Acquires the lock.
|
||||
[summarize older range via the backend]
|
||||
compact/summary → log-only. Provenance: summary, range, shadowed seqs, token count.
|
||||
user/message → surfaceOp { op:'replace', start, end }. THE surface mutation.
|
||||
deriveMessages() renders it as a user-role message.
|
||||
compact/end → log-only. Releases the lock.
|
||||
```
|
||||
|
||||
Ordering the surface mutation **before** `compact/end` is deliberate: `session.append()` commits one event at a time, so there is no multi-event transaction to make the sequence atomic. Releasing the lock last converts the crash window from *silent corruption* (a `compact/end` that claims compaction finished while the surface was never shadowed) into a *detectable orphaned lock* (a `compact/start` with no matching `compact/end`), which a persistence backend already detects on reload. A `session/event` listener on `compact/end` likewise never sees the lock free before the replacement has landed.
|
||||
|
||||
`deriveMessages()` then yields `[summary_as_user_message, ...retained_nodes]`. An alternative — extending `SurfaceEventType` to admit a `compact/*` type — was rejected: the closed union is a deliberate safety boundary (only message-producing events reach the model), and a summary genuinely *is* user-role context, so reusing `user/message` is honest rather than a workaround.
|
||||
|
||||
### Blocking via a log-recorded lock, not a mutex
|
||||
|
||||
Compaction must be serialized: no second compaction starts before the first finishes, and no ordinary events interleave the slow summarization. Rather than an in-memory mutex (invisible to replay, lost on crash), the lock **is** the log: `compactRegion` refuses to start if the last `compact/start` has no matching `compact/end` after it. `compact/start` is appended first (fast, synchronous), the slow model call runs, then the `compact/summary` and `user/message` replacement land, and only then is `compact/end` appended — in a `catch` that records the error, so a failed summarization can never wedge the lock. Because the backend runs compaction synchronously inside the `agent/request` waterfall, the loop is single-threaded for that window; the lock additionally gives observability and lets a persistence backend detect an orphaned `compact/start` on reload.
|
||||
|
||||
## Consequences
|
||||
|
||||
- **New packages**: `packages/compact/compact` (interface) and a sibling `compact-basic` (backend) under `packages/compact/`, wired into the three root tsconfigs. The consumer tier is deferred.
|
||||
- **`SessionEventMap`** gains `compact/start` / `compact/summary` / `compact/end` by declaration merging (merge-extensible); `SurfaceEventType` is **not** touched. These are session events, not cordis `Events`, so the event-taxonomy gate needs no entry.
|
||||
- **No changes** to `dsh-session`, `dsh-invariants`, or `dsh-agent-loop`: the surface replace op, the surface-metadata runtime guard, and the `agent/request` waterfall all already exist. Compaction is a pure plugin on documented seams.
|
||||
- The capability-seams convention gains a second reference beyond bash, and a documented case where "interface depends only on cordis" relaxes to "depends only on interface/vocabulary packages the contract genuinely names." On acceptance, [AGENTS.md](../../../../AGENTS.md) § Conventions and [architecture.md](../../../architecture.md) § "Capability seams" should note this relaxation.
|
||||
@@ -1,31 +0,0 @@
|
||||
# RFC: Stop mirroring durable boundaries as agent events
|
||||
|
||||
Status: proposed
|
||||
|
||||
## Problem
|
||||
|
||||
The loop records the canonical transcript in `SessionEvent` and also emits a parallel set of live `agent/*` mirror events: `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end`, `agent/stream-chunk`, and `agent/steering`. The mirrors make consumers choose between two sources of truth. ACP already chose the session log for the editor-facing transcript because a throwing peer listener can prevent later `agent/*` listeners from observing a boundary, while the session event was already appended. The stdio UI is the only production consumer that still renders turn boundaries and the token stream from the mirror events; it already renders tool calls and results from `session/event`.
|
||||
|
||||
This duplication is not free. Every lifecycle change has to update the session event, the mirror event, docs, invariants, tests, and snapshot expectations. The duplicate boundary events also make failure ordering subtle: a turn can be durably closed before a live `agent/turn-end` listener runs, so a post-boundary listener failure has no valid in-log position left and must be reported out of band.
|
||||
|
||||
## Proposal
|
||||
|
||||
Make `session/event` the live transcript stream. Consumers that render turns, tool calls, tool results, assistant messages, and durable boundaries subscribe to `session/event` and derive their UI from the same event vocabulary persistence uses. Keep agent lifecycle/control events that are not transcript data: `agent/created`, `agent/disposed`, `agent/status`, `agent/error`, and `agent/queued`. `agent/queued` is an inbox acknowledgement rather than a transcript mirror: it fires before any durable event exists, and cancelled queued work may never enter the log.
|
||||
|
||||
Remove the duplicate durable-boundary mirrors from the agent event taxonomy. If a UI wants an agent handle from a session event, it can keep a small map from session id to agent built from `agent/created`/`agent/disposed`, or the registry can offer an explicit lookup. The canonical record remains the event-sourced session log.
|
||||
|
||||
## Acceptance criteria
|
||||
|
||||
- ACP and stdio render transcript content from `session/event`.
|
||||
- `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end`, and `agent/steering` are removed or reduced to private implementation details.
|
||||
- `agent/queued` is either retained and documented as live-only inbox/control state, or deleted in a separate proposal that names the queue-acknowledgement capability loss.
|
||||
- Tests assert the persisted event stream, not a second mirror stream, for turn and step ordering.
|
||||
- Documentation presents `SessionEvent` as both the durable source and the live transcript feed.
|
||||
|
||||
## What we give up
|
||||
|
||||
A plugin can no longer observe turn/step boundaries from a convenient `Agent`-first event. It must either subscribe to `session/event` or maintain a session-to-agent association. That is an acceptable trade: transcript consumers should not depend on a second event feed that can drift from the durable log.
|
||||
|
||||
## Related
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|
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Because high-fidelity `assistant/chunk` persistence remains load-bearing, `agent/stream-chunk` can be evaluated as another mirror of durable session data rather than as the only token stream. If a future proposal moves chunks out of the canonical log, `agent/stream-chunk` would need a fresh decision as a deliberately live-only UI signal.
|
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Reference in New Issue
Block a user