Merge master into compact-tool-result-prune

packages/compact/README.md

@@ -1,6 +1,6 @@
 # compact/ — compaction capability family
 
-A compaction capability family (see [capability seams](../../docs/rfc/implemented/architecture/2026-06-13-capability-seams.md)): an abstract interface, a summarizing backend, a model-free tool-result pruning companion, and a deferred model-facing consumer. All **product** packages.
+A compaction capability family (see [capability seams](../../.agents/notes/implemented/architecture/2026-06-13-capability-seams.md)): an abstract interface, a summarizing backend, a model-free tool-result pruning companion, and a deferred model-facing consumer. All **product** packages.
 
 | Package | Role | ctx key |
 |---|---|---|
@@ -9,4 +9,4 @@ A compaction capability family (see [capability seams](../../docs/rfc/implemente
 | `compact-tool-result-prune/` | Optional model-free head/middle/tail rewriting before summary compaction | `ctx.toolResultPrune` |
 | `tool-compact/` (deferred) | Model-facing `/compact` tool over `ctx.compact` | (registers on `ctx.tools`) |
 
-The interface lives at `compact/compact/`, the backend at `compact/compact-basic/`, and deterministic pruning at `compact/compact-tool-result-prune/`. Unlike the bash seam, the interface depends on `dsh-session` and `dsh-llm` because its verbs are defined over a `Session` and its output uses `ContentBlock`. That deviation is recorded in the [compaction capability-seam RFC](../../docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md). Token measurement remains a reusable LLM-family service; a template- or model-backed compactor can replace `compact-basic` without changing the meter, pruner, or callers.
+The interface lives at `compact/compact/`, the backend at `compact/compact-basic/`, and deterministic pruning at `compact/compact-tool-result-prune/`. Unlike the bash seam, the interface depends on `dsh-session` and `dsh-llm` because its verbs are defined over a `Session` and its output uses `ContentBlock`. That deviation is recorded in the [compaction capability-seam Agent Note](../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md). Token measurement remains a reusable LLM-family service; a template- or model-backed compactor can replace `compact-basic` without changing the meter, pruner, or callers.

packages/compact/compact-basic/README.md

@@ -2,7 +2,7 @@
 
 The **basic compaction backend**: a `BasicCompactService` implementing the `@deepseek-ai/dsh-compact` seam with reusable `ctx.tokenMeter` pressure, token-budget retention, and summarization as a direct one-shot `ctx.llm.stream()` call (interceptable at `llm/stream`).
 
-This is the implementation tier of the compaction capability — see the [interface package](../compact/README.md) for the seam and the [capability-seam RFC](../../../docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md) for the design.
+This is the implementation tier of the compaction capability — see the [interface package](../compact/README.md) for the seam and the [capability-seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md) for the design.
 
 ## What it owns
 
@@ -57,29 +57,45 @@ Loading the plugin registers `ctx.compact`. Add [`dsh-compact-tool-result-prune`
 
 ### Conversation history
 
-**What the model sees**: After a successful step crosses the threshold, oversized tool results are first rewritten when the optional pruner is loaded. If summarization remains necessary, the next request receives the checkpoint preamble below, a blank line, `<compacted-summary>`, the data-dependent summary, and `</compacted-summary>`. Overflow recovery rebuilds the immediate retry from whatever replacement advanced the surface.
+#### What the model sees
 
-**Token effect**: Model-free pruning can avoid the auxiliary call entirely; otherwise it reduces that call's transcript before the summary replaces an older range. A summary remains until a later compaction replaces it, while an indivisible non-tool unit can still exceed the budget.
+After a successful step crosses the threshold, oversized tool results are first rewritten when the optional pruner is loaded. If summarization remains necessary, the next request receives the checkpoint preamble below, a blank line, `<compacted-summary>`, the data-dependent summary, and `</compacted-summary>`. Overflow recovery rebuilds the immediate retry from whatever replacement advanced the surface. A checkpoint replaces the selected older range and is followed by the retained recent units.
 
-#### Conversation checkpoint preamble
+##### Conversation checkpoint preamble
 
 ```markdown
 This is an automatically generated checkpoint condensing an earlier span of the conversation to free up context. Treat the captured context as established background and build on it without restating it. Continue the task directly from the messages that follow, without acknowledging this checkpoint.
 ```
 
+#### Token effect
+
+Model-free pruning can avoid the auxiliary call entirely; otherwise it reduces that call's transcript before the summary replaces an older range. The replacement reduces future input history rather than appending a second copy. A summary remains until a later compaction replaces it, while an indivisible non-tool unit can still exceed the budget.
+
+#### KV Cache effect
+
+Replacing rather than append-only. Each checkpoint invalidates reuse from the first replaced history token; the unchanged request prefix before that range remains reusable.
+
 ### Auxiliary summarizer user message
 
-**What the model sees**: The summarization model receives exactly `Summarize this conversation history:` followed by a blank line, the data-dependent [`renderTranscript()`](../compact/README.md) output, another blank line, and `Summary:`. The conversation model never sees this private request or its reasoning; only returned text is stored.
+#### What the model sees
 
-**Token effect**: This is a separate model call with data-dependent input and `maxTokens`-capped output. Convergence retries can pay this cost more than once.
+The summarization model receives exactly `Summarize this conversation history:` followed by a blank line, the data-dependent [`renderTranscript()`](../compact/README.md) output, another blank line, and `Summary:`. The conversation model never sees this private request or its reasoning; only returned text is stored.
+
+#### Token effect
+
+This is a separate model call with data-dependent input and `maxTokens`-capped output. Convergence retries can pay this cost more than once.
+
+#### KV Cache effect
+
+Independent of the conversation request cache. An auxiliary call can reuse an exact transcript prefix, while a different selected range or rendering invalidates reuse from its first changed token.
 
 ### Auxiliary summarizer system prompt
 
-**What the model sees**: The summarization model receives the checkpoint-writing instruction below.
+#### What the model sees
 
-**Token effect**: Fixed auxiliary input cost plus the data-dependent transcript on every summarization attempt.
+The summarization model receives the checkpoint-writing instruction below.
 
-#### Auxiliary summarizer system prompt
+##### Auxiliary summarizer system prompt
 
 ```markdown
 You are a compaction engine for an AI coding assistant. Condense the conversation transcript into a structured checkpoint that lets another model resume the work with no loss of essential context.
@@ -117,6 +133,14 @@ Rules:
 - If the transcript already contains a <compacted-summary> block, it is a PRIOR checkpoint. Do not copy it forward verbatim: preserve still-true facts, drop stale ones, and merge newer information into a single consolidated summary under the same structure.
 ```
 
+#### Token effect
+
+Fixed auxiliary input cost plus the data-dependent transcript on every summarization attempt.
+
+#### KV Cache effect
+
+Prefix-stable for auxiliary calls while this instruction and the summarizer route are unchanged. Changing either starts a different prefix; transcript changes occur after the instruction.
+
 ## Known Limitations and Deferred Work
 
 - **Meter accuracy follows the fixed heuristic** — missing reusable provider usage falls back to character count plus structural overhead rather than exact tokenization.
@@ -124,4 +148,4 @@ Rules:
 - **Some indivisible-unit and envelope-only overflow remains outside surface compaction** — recovery cannot shrink system/tools/prefix, split an indivisible non-tool node, or repair a tool unit whose non-prunable remainder still exceeds the window. The optional pruner can shrink text-bearing tool-result bulk inside an otherwise indivisible pair.
 - **`compactRegion` requires an open turn** — a manual call on a fully-closed session throws ("no open turn") rather than compacting.
 - **Summarization failure preserves the latest durable surface** — before any replacement, the auto path logs a warning and proceeds with full over-budget history. If pruning already landed, a later summarization failure proceeds from that durable pruned surface. Summarization truncation at `maxTokens`, which hidden reasoning tokens can consume, follows the same rule.
-- **The summarization call has no transcript-snapshot coverage** — `dsh-llm-replay` derives calls from `assistant/chunk` events, so this chunk-less direct `ctx.llm.stream()` call cannot replay (named deferred replay infrastructure in [the seam RFC](../../../docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md)).
+- **The summarization call has no transcript-snapshot coverage** — `dsh-llm-replay` derives calls from `assistant/chunk` events, so this chunk-less direct `ctx.llm.stream()` call cannot replay (named deferred replay infrastructure in [the seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md)).

packages/compact/compact-tool-result-prune/README.md

@@ -39,9 +39,17 @@ export function apply(ctx: Context): void {
 
 ### Pruned tool result
 
-**What the model sees**: Once a compaction trigger qualifies, future requests see the retained head, `\n\n[... tool result middle pruned ...]\n\n`, and retained tail in place of the removed text. Rich blocks keep their order. The model does not see a second copy of the original.
+#### What the model sees
 
-**Token effect**: Each rewritten tool result has at most `thresholdChars` text code points. Pruning itself makes no model call; compact-basic skips summarization when the remeasured request falls below pressure, otherwise the summarizer reads the pruned surface.
+Once a compaction trigger qualifies, future requests see the retained head, `\n\n[... tool result middle pruned ...]\n\n`, and retained tail in place of the removed text. Rich blocks keep their order. The model does not see a second copy of the original.
+
+#### Token effect
+
+Each rewritten tool result has at most `thresholdChars` text code points. Pruning itself makes no model call; compact-basic skips summarization when the remeasured request falls below pressure, otherwise the summarizer reads the pruned surface.
+
+#### KV Cache effect
+
+Replacing an earlier result invalidates the reusable request prefix from that result onward; subsequent requests reuse the new pruned prefix until another surface replacement occurs.
 
 ## Known Limitations and Deferred Work
 

packages/compact/compact/README.md

@@ -10,7 +10,7 @@ This package is the interface tier of the compaction capability, split so each c
 | `@deepseek-ai/dsh-compact-basic` | a backend: `ctx.tokenMeter` pressure + token-budget retention + `llm.stream()` summarization |
 | `@deepseek-ai/dsh-tool-compact` (deferred) | the model-facing `/compact` tool over `ctx.compact` |
 
-Unlike the bash seam, this interface depends on `@deepseek-ai/dsh-session` and `@deepseek-ai/dsh-llm` — the contract's verbs are defined over a `Session` and its output is the `ContentBlock` vocabulary, so they cannot be expressed without naming those packages. That deviation from the "interface depends only on cordis" guidance is intentional and recorded in the [compaction capability-seam RFC](../../../docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md).
+Unlike the bash seam, this interface depends on `@deepseek-ai/dsh-session` and `@deepseek-ai/dsh-llm` — the contract's verbs are defined over a `Session` and its output is the `ContentBlock` vocabulary, so they cannot be expressed without naming those packages. That deviation from the "interface depends only on cordis" guidance is intentional and recorded in the [compaction capability-seam Agent Note](../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md).
 
 ## Service API (`ctx.compact`)
 
@@ -61,15 +61,31 @@ Subclass `CompactService`, implement `compactIfNeeded` and `compactRegion`, and
 
 ### Conversation history, when a backend is invoked
 
-**What the model sees**: A successful implementation replaces an older surface range with one user-role summary checkpoint; the raw events stay logged but stop appearing in derived model messages. The seam itself performs no rewrite.
+#### What the model sees
 
-**Token effect**: Zero direct tokens from this interface. A backend trades many retained history tokens for one summary and leaves the recent tail unchanged.
+A successful implementation replaces an older surface range with one user-role summary checkpoint; the raw events stay logged but stop appearing in derived model messages. The seam itself performs no rewrite.
+
+#### Token effect
+
+Zero direct tokens from this interface. A backend trades many retained history tokens for one summary and leaves the recent tail unchanged.
+
+#### KV Cache effect
+
+A successful backend replacement invalidates reuse from the first shadowed history token; the seam itself does not alter a request.
 
 ### Transcript supplied to a compaction consumer
 
-**What the model sees**: `renderTranscript()` joins entries with one blank line and renders them exactly as `User: <content>`, `Assistant: <content>`, `Tool result (call <callId>): <content>`, `Tool error (call <callId>): <content>`, `[Context: <content>]`, or `[Steering: <content>]`. Non-text blocks render exactly as `[reasoning: <text>]`, `[tool-call: <name>(<arguments>)]`, `[tool-result: <content>]`, `[tool-result]`, or `[<block-type>]`.
+#### What the model sees
 
-**Token effect**: Data-dependent input tokens are paid only by the auxiliary model or consumer that requests this transcript; the conversation model does not receive a duplicate transcript.
+`renderTranscript()` joins entries with one blank line and renders them exactly as `User: <content>`, `Assistant: <content>`, `Tool result (call <callId>): <content>`, `Tool error (call <callId>): <content>`, `[Context: <content>]`, or `[Steering: <content>]`. Non-text blocks render exactly as `[reasoning: <text>]`, `[tool-call: <name>(<arguments>)]`, `[tool-result: <content>]`, `[tool-result]`, or `[<block-type>]`.
+
+#### Token effect
+
+Data-dependent input tokens are paid only by the auxiliary model or consumer that requests this transcript; the conversation model does not receive a duplicate transcript.
+
+#### KV Cache effect
+
+No conversation-cache invalidation. A consumer's auxiliary request can reuse only the exact prefix produced by this rendering; changed or compacted entries invalidate reuse from their first difference.
 
 ## Known Limitations and Deferred Work
 

packages/compact/compact/src/index.ts

@@ -3,7 +3,7 @@
  * compact and replace a history range with one summary node by subclassing
  * {@link CompactService}. This interface necessarily depends on session and LLM
  * vocabulary; the rationale is in the
- * [compaction RFC](../../../../docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md).
+ * [compaction Agent Note](../../../../.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md).
  * @module @deepseek-ai/dsh-compact
  */
 

packages/compact/compact/src/types.ts

@@ -3,7 +3,7 @@
  * Those declaration-merged events are log-only lock/provenance markers, not
  * surface events; a separate replacement `user/message` carries the summary.
  * Backend packages own configuration and retention policy; see
- * `docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md`.
+ * `.agents/notes/implemented/feature/2026-06-18-compaction-capability-seam.md`.
  * @module @deepseek-ai/dsh-compact/types
  */
 
@@ -30,7 +30,7 @@ declare module '@deepseek-ai/dsh-session' {
        * The model that wrote the summary — the summarize call's envelope,
        * reported by the backend that made the call, logged so the one-shot
        * request is reconstructable from log + code and "which model wrote
-       * this summary" has a durable answer (the reconstructability RFC).
+       * this summary" has a durable answer (the reconstructability Agent Note).
        */
       model: string
       /** The generation cap the summarize call sent, when one applied. */