Merge remote-tracking branch 'origin/master' into worktree-hooks-a-taxonomy

# Conflicts:
#	docs/rfc/README.md

docs/cookbook/adding-a-tool.md

@@ -36,6 +36,7 @@ Registration is effect-based: disposing the plugin fiber unregisters the tool (w
 - **Args are validated for you.** `defineTool` validates the model-generated `arguments` against the `SchemaSpec` before `execute` runs (type, required keys, enum membership, nested objects/arrays — [runtime arg validation](../rfc/implemented/architecture/2026-06-11-runtime-arg-validation.md)), so inside `execute` the args already match `InferArgs`. You still hand-check value constraints the DSL can't express (non-empty strings, positive numbers, cross-field rules); throw a descriptive Error for those. Raw JSON-Schema tools registered directly (MCP) are NOT validated by the harness — they validate their own input.
 - **Throwing means isError.** The registry catches anything `execute()` throws and returns `{isError: true}` to the model. Use that for infrastructure failures (bad input, spawn errors, aborts) — but REPORT domain failures in the result text instead (e.g. tool-bash returns `[exit code: 9]` with `isError: false`: the model decides what a failing command means).
 - **Honor `exec.signal`.** Cancel in-flight work when it fires.
+- **Attach durable card data with `meta` (optional).** `execute` may return `{ content, meta }` instead of a bare `ContentBlock[]` — `meta` is a JSON-serializable payload the core treats as opaque, persisted on the `tool/result` event and handed back to your `presentResult` (so a card that needs more than `args`, like `write`/`edit`'s applied-hunk diff, survives a session replay). Keep UI-only data here, never in the model-facing `content`.
 - **Use `exec.agent` for async notifications.** `agent.inject(content, {source: {kind: 'plugin', plugin: '<name>'}})` appends durable context the NEXT model request sees — it is not a wake-up (an idle agent stays idle). Guard against disposed agents (try/catch).
 
 ## Long-running work
@@ -48,6 +49,26 @@ Follow tool-bash's background pattern: a `run_in_background` flag returns a task
 
 Prefer not to build policy into the tool. The seam is the `tools/execute` waterfall (veto or wrap — see the permission-gate example in [extension-cookbook.md](./extension-cookbook.md)), or a sandboxing implementation behind the tool's executor seam.
 
+## How your tool renders in an editor (ACP presentation)
+
+Your tool's `execute` returns model-facing content; its **editor card** is a separate, optional concern you declare with two pure display methods on the `defineTool` options. Design this alongside `execute`, not after — an editor (Zed, over the ACP bridge) shows the card, and a tool with no presentation falls back to a bland generic card (title = tool name, raw args as input).
+
+Both methods return a **`card`-tagged render intent** — pick the card kind that matches what your tool does:
+
+- `presentCall(args)` → a `ToolCallView` (the PENDING card):
+  - `{ card: 'generic', title, kind?, rawInput?, content?, locations? }` — the default. Set `kind` for an icon (`read`/`search`/…); set `locations: [{ path, line? }]` for any file your tool touches so a capable editor follows along / jumps to it.
+  - `{ card: 'terminal', title, description?, cwd? }` — your call IS a shell command. `title` is the command, `description` renders above the terminal card. (tool-bash.)
+  - `{ card: 'diff', title, diffs, locations? }` — your call creates or modifies a file. `diffs: [{ path, oldText, newText }]` (`oldText: null` for a new file) renders as an inline diff card. (tool-fs `write`/`edit`.)
+- `presentResult(args, { content, isError, meta? })` → a `ToolResultView` (the COMPLETED card): `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }` (the run's captured output + exit — the bridge shows an exit pill and derives a fenced ` ```console ` fallback for editors without the terminal capability), or `{ card: 'diff', title?, diffs }` (a completed file mutation — the applied hunks computed from the before/after content when there is a before-image, else a whole-file diff for a create; `write`/`edit` attach the hunks via the `meta` channel and read them back here). A mutation tool returns the `diff` result even when it duplicates the call-time card, because an ACP `tool_call_update.content` REPLACES the call's content — a non-diff result would clobber the pending diff. `result.meta` is your tool's own optional presentation payload, attached from `execute` (see below) and persisted so a replay reproduces the card.
+
+Hard rules (they bite if broken):
+
+- **Purity.** These run on live streaming AND on session-log REPLAY, so they must be pure functions of `args` (+ the result) — NO I/O, NO reading session state, NO clock/random. A diff is derived from the args (`write` uses `oldText: null` because a call-time presenter has no prior file content); the BRIDGE, not the tool, fills the session cwd and relativizes a display-path title. If you find yourself wanting the file's old content or the working directory inside `presentCall`, stop — that belongs on the bridge or a future result-event shape, not the presenter.
+- **UI-only formatting stays out of the model result.** A fenced ` ```console ` block, a diff, a relativized path — none of these may appear in what `execute` returns to the model; they live only in the presentation. (A `terminal` result view carries RAW `output`; the bridge adds the fences.)
+- **`defineTool` soft-validates the display path.** A malformed/older logged arg shape makes the wrapper return `undefined` (a generic fallback) rather than throw — display must never crash a replay.
+
+The neutral vocabulary lives in `dsh-tools` (never import an ACP type into a tool); the ACP bridge maps each `card` to the wire. The design and the why are in [the render-intent-union RFC](../rfc/implemented/architecture/2026-07-02-tool-render-intent-union.md); `dsh-tool-fs` (generic/diff) and `dsh-tool-bash` (terminal) are the reference implementations.
+
 ## Tests every tool needs
 
-Arg-validation rejections, result shaping for every outcome, the HMR disposal test, and — for tools with side effects — an integration spec that drives the tool through the agent loop with a scripted `MockAdapter` (`packages/core/agent-loop/tests/mock-adapter.ts`), asserting the `tool/call` / `tool/result` session events.
+Arg-validation rejections, result shaping for every outcome, the HMR disposal test, and — for tools with side effects — an integration spec that drives the tool through the agent loop with a scripted `MockAdapter` (`packages/core/agent-loop/tests/mock-adapter.ts`), asserting the `tool/call` / `tool/result` session events. **If your tool has an editor card, also add:** a unit test on `presentCall`/`presentResult` asserting the exact view shape, AND — because a unit test proves the shape but not that an editor renders it — a **snapshot scenario** under `examples/acp-agent/tests/snapshots/` that drives the real tool through the ACP bridge and pins the rendered `tool_call` transcript (the card kind is only verified end-to-end there; see the [ACP snapshot-tests RFC](../rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md)). A tool whose card is a `terminal` needs a scenario whose `input.json` sets `terminalOutput: true` to exercise the capable-client `_meta` path.

docs/cookbook/extension-cookbook.md

@@ -83,4 +83,4 @@ export function apply(ctx: Context) {
 
 ## Runnable wirings
 
-Three complete examples load their plugin trees from `cordis.yml`: [`examples/echo-agent`](../../examples/echo-agent) (mock model + echo tool — the all-mock skeleton check, `pnpm run demo:echo`), [`examples/coding-agent`](../../examples/coding-agent) (DeepSeek V4 + the bash tool suite — the real thing, `pnpm run demo:coding`), and [`examples/acp-agent`](../../examples/acp-agent) (the same coding agent exposed as an ACP server over JSON-RPC stdio — the client-driver shape, `pnpm run demo:acp`). Each leaf is now just its swappable backends plus an app-package entry: the stdio demos load [`@deepseek-ai/dsh-stdio-agent`](../../packages/ui/stdio-agent), the ACP demo loads [`@deepseek-ai/dsh-acp-agent`](../../packages/ui/acp-agent), and both app packages share the spine via the [`@deepseek-ai/dsh-agent-core`](../../packages/core/agent-core) bundle.
+Three complete examples load their plugin trees from `cordis.yml`: [`examples/echo-agent`](../../examples/echo-agent) (mock model + echo tool — the all-mock skeleton check, `pnpm run demo:echo`), [`examples/coding-agent`](../../examples/coding-agent) (DeepSeek V4 + the bash tool suite behind a terminal REPL UI, `pnpm run demo:repl`), and [`examples/acp-agent`](../../examples/acp-agent) (an agent exposed as an ACP server over JSON-RPC stdio — the client-driver shape, `pnpm run demo:acp`). Each leaf is now just its swappable backends plus an app-package entry: the stdio demos load [`@deepseek-ai/dsh-stdio-agent`](../../packages/ui/stdio-agent), the ACP demo loads [`@deepseek-ai/dsh-acp-agent`](../../packages/ui/acp-agent), and both app packages share the spine via the [`@deepseek-ai/dsh-agent-core`](../../packages/core/agent-core) bundle.