feat(acp): tool-owned tool-call UI presentation (title/command/output)

In Zed the tool-call card showed only "bash" — the bare tool name — instead
of what the command does. Fix it by letting each TOOL own how its calls render,
rather than the bridge special-casing names.

dsh-tools: add an optional two-state presentation seam to ToolDefinition /
defineTool — `presentCall(args)` (pending: title, kind, rawInput) and
`presentResult(args, result)` (completed: title?, content?). Provider-neutral
`ToolCallKind`/`ToolCallPresentation`/`ToolResultPresentation` vocabulary so
tools never depend on ACP. defineTool soft-validates args (display runs on log
replay, so a malformed/old shape returns undefined instead of throwing).

dsh-tool-bash: bash declares presentCall (model `description` → title, exact
`command` → rawInput, kind execute) and presentResult (wrap output in a fenced
```console block — a UI-only affordance kept out of the model-facing result);
bash_output/bash_kill present task-scoped titles.

dsh-acp: inject `tools`; a per-session `ToolPresenter` looks the tool up by name
and maps its neutral presentation to the ACP tool_call/tool_call_update wire
shape, with a generic fallback (title = name) for tools that declare nothing.
Because the `tool/result` event carries only {callId, content, isError}, the
presenter keeps a small bridge-local map of ONLY in-flight calls' (name, args),
keyed by callId and removed as each result is presented — no event-schema or
core change. Replay uses a throwaway presenter so loaded sessions render
identically to live ones.

Tests: dsh-tools defineTool presenters (typed args, soft-validate), tool-bash
bash/bash_output/bash_kill presenters, acp ToolPresenter (tool-owned mapping,
unknown-callId fallback, in-flight-only map), and an end-to-end turn through the
bridge. The key-gated e2e now asserts a real bash call's title is the model
description (not "bash") and rawInput is the command — verified against the real
DeepSeek model. The test harness derives its inject from the bridge's exported
`inject` so it can't drift again.

packages/acp/src/index.ts

@@ -60,6 +60,7 @@ import {
 import type { ContentBlock } from '@deepseek-ai/dsh-llm'
 import type { Agent, AgentStatus } from '@deepseek-ai/dsh-agent'
 import type { SessionEvent } from '@deepseek-ai/dsh-session'
+import type { ToolCallKind, ToolRegistry } from '@deepseek-ai/dsh-tools'
 // Side-effect type import: declaration-merges `ctx.sessionPersistence` onto
 // Context (the bridge injects it and reads `list()` for load cwd validation).
 import type {} from '@deepseek-ai/dsh-session-persistence'
@@ -73,8 +74,10 @@ import {
 export const name = 'acp'
 // The bridge programs against the interface packages only (architecture rule:
 // plugins never depend on dsh-agent-loop). `sessionPersistence` is required
-// because `initialize` advertises `loadSession: true`.
-export const inject = ['agents', 'sessions', 'sessionPersistence']
+// because `initialize` advertises `loadSession: true`. `tools` lets a tool own
+// how its calls render (`presentCall`/`presentResult`); the bridge looks up the
+// definition by name and falls back to a generic presentation when absent.
+export const inject = ['agents', 'sessions', 'sessionPersistence', 'tools']
 
 /**
  * Build an ACP "invalid params" error whose human detail rides in the message.
@@ -131,6 +134,13 @@ export const Config: Schema<AcpConfig> = Schema.object({
 interface SessionRecord {
   sessionId: string
   agent: Agent
+  /**
+   * Resolves tool-owned presentation for THIS session's tool calls and remembers
+   * each in-flight call's `(name, args)` so the matching `tool/result` can find
+   * its tool. Per-session so two concurrent sessions never cross their in-flight
+   * tool state.
+   */
+  presenter: ToolPresenter
   /**
    * The in-flight `session/prompt`, or `undefined` when none is pending. A
    * prompt resolves with a {@link StopReason} or rejects with an Error (a
@@ -182,6 +192,7 @@ export function apply(ctx: Context, config: AcpConfig): void {
   const agents = ctx.agents
   const sessionPersistence = ctx.sessionPersistence
   const logger = ctx.logger
+  const tools = ctx.tools
 
   // Live sessions keyed by id (RFC 011 multi-session), plus an agent→sessionId
   // reverse map so `agent/*` events (which carry only the Agent) demux in O(1).
@@ -270,7 +281,7 @@ export function apply(ctx: Context, config: AcpConfig): void {
   ctx.on('session/event', (session, event: SessionEvent) => {
     const rec = sessions.get(session.header.id)
     if (rec === undefined) return
-    streamSessionEventUpdate(rec.sessionId, event, notify)
+    streamSessionEventUpdate(rec.sessionId, event, notify, rec.presenter)
     const inflight = rec.inflight
     if (inflight === undefined) return
     if (event.type === 'turn/start') {
@@ -395,7 +406,7 @@ export function apply(ctx: Context, config: AcpConfig): void {
           agentOptions: agentOptions(config),
         })
         bySession.set(agent, sessionId)
-        sessions.set(sessionId, { sessionId, agent, inflight: undefined })
+        sessions.set(sessionId, { sessionId, agent, presenter: new ToolPresenter(tools), inflight: undefined })
         return Promise.resolve({ sessionId })
       },
 
@@ -448,14 +459,18 @@ export function apply(ctx: Context, config: AcpConfig): void {
             throw invalidParams('connection closed during session/load')
           }
           bySession.set(agent, params.sessionId)
-          sessions.set(params.sessionId, { sessionId: params.sessionId, agent, inflight: undefined })
+          const record: SessionRecord = { sessionId: params.sessionId, agent, presenter: new ToolPresenter(tools), inflight: undefined }
+          sessions.set(params.sessionId, record)
           // Replay the persisted event log to the client as session/update. Use
           // the raw event log (NOT deriveMessages, which drops assistant/chunk
           // and trace events): RFC 010's load contract reconstructs the streamed
           // turns — user prompts (user/message → user_message_chunk), assistant
-          // text and reasoning (assistant/chunk), and tool calls/results.
+          // text and reasoning (assistant/chunk), and tool calls/results. The
+          // record's presenter pairs each tool/call with its tool/result as the
+          // log replays in order, so the replayed tool cards render identically
+          // to the live ones.
           for (const event of agent.session.events) {
-            streamSessionEventUpdate(params.sessionId, event, notify)
+            streamSessionEventUpdate(params.sessionId, event, notify, record.presenter)
           }
           return {}
         } finally {
@@ -659,6 +674,14 @@ function validateWorkspaceParams(params: { cwd: string; additionalDirectories?:
  * - `tool/call`   → `tool_call` (pending)
  * - `tool/result` → `tool_call_update` (completed/failed)
  *
+ * Tool-call presentation (title/kind/rawInput, and the completed-state content)
+ * is owned by each TOOL via `presentCall`/`presentResult` — the bridge never
+ * special-cases tool names. `presenter` resolves those from the tool registry
+ * and remembers each call's `(name, args)` so the completed `tool/result` (which
+ * carries neither) can find its tool. A {@link nullToolPresenter} gives the
+ * generic fallback (title = tool name, raw args as input) when no registry is
+ * available (e.g. pure translator tests).
+ *
  * Other event types (turn/step boundaries, context/message, usage, …) produce
  * no client update.
  */
@@ -666,6 +689,7 @@ export function streamSessionEventUpdate(
   sessionId: string,
   event: SessionEvent,
   notify: (notification: SessionNotification) => void,
+  presenter: Pick<ToolPresenter, 'call' | 'result'> = nullToolPresenter,
 ): void {
   switch (event.type) {
     case 'assistant/chunk': {
@@ -690,27 +714,30 @@ export function streamSessionEventUpdate(
       return
     }
     case 'tool/call': {
+      const present = presenter.call(event.data.callId, event.data.name, event.data.arguments)
       notify({
         sessionId,
         update: {
           sessionUpdate: 'tool_call',
           toolCallId: event.data.callId,
-          title: event.data.name,
-          kind: toolKindFor(event.data.name),
+          title: present.title,
+          kind: present.kind,
           status: 'in_progress',
-          rawInput: parseToolArguments(event.data.arguments),
+          ...present.rawInput !== undefined ? { rawInput: present.rawInput } : {},
         },
       })
       return
     }
     case 'tool/result': {
+      const present = presenter.result(event.data.callId, event.data.content, event.data.isError)
       notify({
         sessionId,
         update: {
           sessionUpdate: 'tool_call_update',
           toolCallId: event.data.callId,
           status: event.data.isError ? 'failed' : 'completed',
-          content: toolResultContent(event.data.content),
+          content: toolResultContent(present.content),
+          ...present.title !== undefined ? { title: present.title } : {},
         },
       })
       return
@@ -722,8 +749,84 @@ export function streamSessionEventUpdate(
   }
 }
 
+/**
+ * Resolved pending-state presentation the bridge feeds into a `tool_call`
+ * update: a title is always present (tool name when the tool gives none), `kind`
+ * and `rawInput` are optional.
+ */
+interface ResolvedCallPresentation {
+  title: string
+  kind: ToolCallKind
+  rawInput?: unknown
+}
+
+/** Resolved completed-state presentation fed into a `tool_call_update`. */
+interface ResolvedResultPresentation {
+  /** UI content for the result (harness blocks; the tool may reformat, else the raw result). */
+  content: ContentBlock[]
+  /** Optional replacement title for the completed call. */
+  title?: string
+}
+
+/**
+ * Resolves tool-owned presentation for a session's tool-call events. A tool
+ * declares `presentCall`/`presentResult` (see `dsh-tools`); this looks them up
+ * by name in the registry and applies the generic fallback when a tool defines
+ * neither.
+ *
+ * The `tool/result` session event carries only `{ callId, content, isError }` —
+ * NOT the tool name or args — so to call a tool's `presentResult` (which needs
+ * both), the presenter remembers each `tool/call`'s `{ name, args }` keyed by
+ * callId and looks it up on the matching result. The map is bridge-LOCAL (not a
+ * change to the event schema or a core service): one presenter per live session
+ * (and a throwaway per `session/load` replay), entries removed as each result
+ * arrives, so it holds only the currently-in-flight calls.
+ */
+export class ToolPresenter {
+  private readonly pending = new Map<string, { name: string; args: unknown }>()
+
+  constructor(private readonly tools: Pick<ToolRegistry, 'get'>) {}
+
+  /** Pending-state presentation for a `tool/call`; remembers `(name, args)` for the matching result. */
+  call(callId: string, name: string, argsJson: string): ResolvedCallPresentation {
+    const args = parseToolArguments(argsJson)
+    this.pending.set(callId, { name, args })
+    const present = this.tools.get(name)?.presentCall?.(args)
+    if (present === undefined) {
+      // No tool-owned presentation: fall back to the tool name as the title and
+      // the full parsed args as the raw input (the pre-seam behavior).
+      return { title: name, kind: toolKindFor(name), rawInput: args }
+    }
+    return { title: present.title, kind: present.kind ?? 'other', rawInput: present.rawInput }
+  }
+
+  /** Completed-state presentation for a `tool/result`; consumes the remembered `(name, args)`. */
+  result(callId: string, content: ContentBlock[], isError: boolean): ResolvedResultPresentation {
+    const call = this.pending.get(callId)
+    this.pending.delete(callId)
+    const present = call !== undefined
+      ? this.tools.get(call.name)?.presentResult?.(call.args, { content, isError })
+      : undefined
+    if (present === undefined) return { content }
+    return {
+      content: present.content ?? content,
+      ...present.title !== undefined ? { title: present.title } : {},
+    }
+  }
+}
+
+/**
+ * The no-op presenter used when no tool registry is available (e.g. the pure
+ * translator tests): every tool gets the generic fallback presentation, and
+ * results pass their raw content through unchanged.
+ */
+export const nullToolPresenter: Pick<ToolPresenter, 'call' | 'result'> = {
+  call: (_callId, name, argsJson) => ({ title: name, kind: toolKindFor(name), rawInput: parseToolArguments(argsJson) }),
+  result: (_callId, content) => ({ content }),
+}
+
 /** Map a harness tool name to an ACP ToolKind (best-effort; default `other`). */
-function toolKindFor(name: string): 'read' | 'edit' | 'delete' | 'move' | 'search' | 'execute' | 'fetch' | 'other' {
+function toolKindFor(name: string): ToolCallKind {
   if (name === 'bash' || name === 'bash_output' || name === 'bash_kill') return 'execute'
   if (name === 'read' || name.startsWith('read')) return 'read'
   if (name === 'write' || name === 'edit' || name.startsWith('edit')) return 'edit'