fix(agent-chat): show ACP paths and diffs for tool calls

agent-chat/adapters/acp.ts

@@ -490,7 +490,7 @@ function handleAgentMessage(sess: SessionCtx, st: AcpState, def: ProviderDef, ms
           kind: "tool-start",
           toolId: u.toolCallId,
           name: u.title ?? u.kind ?? "tool",
-          detail: truncate(JSON.stringify(u.rawInput ?? {})),
+          detail: acpToolCallDetail(u.locations, u.rawInput),
         });
         break;
       case "tool_call_update":
@@ -573,10 +573,34 @@ function normalizeCommands(commands: any): CommandEntry[] {
   })).filter((c) => c.name);
 }
 
-function contentText(content: unknown): string {
+export function acpToolCallDetail(locations: unknown, rawInput: unknown): string {
+  const paths = Array.isArray(locations)
+    ? locations
+      .map((location: any) => typeof location?.path === "string" ? location.path : "")
+      .filter(Boolean)
+    : [];
+  return truncate(paths.length ? paths.join(", ") : JSON.stringify(rawInput ?? {}));
+}
+
+function lineCount(text: string): number {
+  return text ? text.split(/\r\n|\r|\n/).length : 0;
+}
+
+function diffText(content: any): string {
+  const oldText = typeof content.oldText === "string" ? content.oldText : "";
+  const newText = typeof content.newText === "string" ? content.newText : "";
+  const path = typeof content.path === "string" && content.path ? content.path : "unknown path";
+  return `diff ${path} (+${lineCount(newText)}/-${lineCount(oldText)})${newText ? `\n${newText}` : ""}`;
+}
+
+export function contentText(content: unknown): string {
   if (!Array.isArray(content)) return "";
   return content
-    .map((c: any) => c?.content?.text ?? c?.text ?? "")
+    .map((c: any) => {
+      if (c?.type === "diff") return diffText(c);
+      if (c?.type === "terminal") return `terminal ${String(c.terminalId ?? "")}`.trim();
+      return c?.content?.text ?? c?.text ?? "";
+    })
     .join("");
 }
 

agent-chat/test/acp-tool-detail.test.ts

@@ -0,0 +1,56 @@
+import { expect, test } from "bun:test";
+import { makeAcpAdapter } from "../adapters/acp";
+import type { AgentEvent, ProviderDef, SessionCtx, SessionStatus } from "../types";
+
+test("shows ACP tool locations and every tool output variant", async () => {
+  const def: ProviderDef = {
+    id: "fake-acp-tool-detail",
+    label: "Fake ACP Tool Detail",
+    adapter: "acp",
+    cmd: ["bun", `${import.meta.dir}/fake-acp-tool-detail.ts`],
+  };
+  const adapter = makeAcpAdapter(def);
+  const events: AgentEvent[] = [];
+  const sess: SessionCtx = {
+    id: "fake-tool-detail-session",
+    provider: def.id,
+    cwd: `${import.meta.dir}/../scratch`,
+    title: "fake ACP tool detail",
+    autoApprove: true,
+    startOptions: {},
+    status: "idle",
+    events,
+    internal: {},
+    emit(evt: AgentEvent) {
+      events.push(evt);
+    },
+    setStatus(status: SessionStatus) {
+      this.status = status;
+    },
+  };
+
+  try {
+    await adapter.send(sess, "show tool details");
+
+    const starts = events.filter((event) => event.kind === "tool-start");
+    expect(starts).toEqual([
+      { kind: "tool-start", toolId: "located", name: "Edit files", detail: "src/one.ts, src/two.ts" },
+      { kind: "tool-start", toolId: "raw-input", name: "Inspect files", detail: '{"command":"cat README.md"}' },
+    ]);
+
+    const ends = events.filter((event) => event.kind === "tool-end");
+    expect(ends.find((event) => event.toolId === "new-file")?.detail).toContain("src/new.ts");
+    expect(ends.find((event) => event.toolId === "new-file")?.detail).toContain("+2/-0");
+    expect(ends.find((event) => event.toolId === "new-file")?.detail).toContain("one two");
+
+    expect(ends.find((event) => event.toolId === "changed-file")?.detail).toContain("src/changed.ts");
+    expect(ends.find((event) => event.toolId === "changed-file")?.detail).toContain("+2/-1");
+
+    const mixed = ends.find((event) => event.toolId === "mixed")?.detail ?? "";
+    expect(mixed).toContain("text output");
+    expect(mixed).toContain("src/mixed.ts");
+    expect(mixed).toContain("term-42");
+  } finally {
+    adapter.dispose(sess);
+  }
+});

agent-chat/test/fake-acp-tool-detail.ts

@@ -0,0 +1,55 @@
+import { createInterface } from "node:readline";
+
+const send = (msg: unknown) => {
+  process.stdout.write(`${JSON.stringify(msg)}\n`);
+};
+
+for await (const line of createInterface({ input: process.stdin })) {
+  if (!line.trim()) continue;
+  const msg = JSON.parse(line);
+  if (msg.method === "initialize") {
+    send({ jsonrpc: "2.0", id: msg.id, result: { protocolVersion: 1 } });
+  } else if (msg.method === "session/new") {
+    send({ jsonrpc: "2.0", id: msg.id, result: { sessionId: "fake-tool-detail" } });
+  } else if (msg.method === "session/prompt") {
+    const notify = (update: unknown) => send({ jsonrpc: "2.0", method: "session/update", params: { update } });
+    notify({
+      sessionUpdate: "tool_call",
+      toolCallId: "located",
+      title: "Edit files",
+      rawInput: { command: "edit" },
+      locations: [{ path: "src/one.ts", line: 4 }, { path: "src/two.ts" }],
+    });
+    notify({
+      sessionUpdate: "tool_call",
+      toolCallId: "raw-input",
+      title: "Inspect files",
+      rawInput: { command: "cat README.md" },
+    });
+    notify({
+      sessionUpdate: "tool_call_update",
+      toolCallId: "new-file",
+      status: "completed",
+      content: [{ type: "diff", path: "src/new.ts", oldText: null, newText: "one\ntwo" }],
+    });
+    notify({
+      sessionUpdate: "tool_call_update",
+      toolCallId: "changed-file",
+      status: "completed",
+      content: [{ type: "diff", path: "src/changed.ts", oldText: "old", newText: "new\nlines" }],
+    });
+    notify({
+      sessionUpdate: "tool_call_update",
+      toolCallId: "mixed",
+      status: "completed",
+      content: [
+        { type: "content", content: { type: "text", text: "text output" } },
+        { type: "diff", path: "src/mixed.ts", oldText: "old", newText: "new" },
+        { type: "terminal", terminalId: "term-42" },
+      ],
+    });
+    send({ jsonrpc: "2.0", id: msg.id, result: { stopReason: "end_turn" } });
+  } else if (msg.id != null) {
+    send({ jsonrpc: "2.0", id: msg.id, result: {} });
+  }
+}