#60: live turn progress (activity line + token count + OutputChannel stream + cancel) (#61)

Surface Claude live output/progress during the asking-Claude status: notification activity line + token count, a Cowriting: Claude OutputChannel streaming assistant text, and a cancellable turn. Pure turnProgress reducer + runEditTurn onProgress/AbortSignal (vscode-free) + both call sites. INV-43..47.

Fixes #60

src/liveTurn.ts

@@ -9,6 +9,9 @@
  * never bundled (esbuild keeps it external).
  */
 
+import type { TurnProgressSnapshot } from "./turnProgress";
+import { createTurnProgressState, reduceTurnProgress } from "./turnProgress";
+
 export interface EditTurnResult {
   replacement: string;
   model: string;
@@ -16,6 +19,19 @@ export interface EditTurnResult {
   sessionId: string;
 }
 
+/**
+ * Options for runEditTurn. Both new fields are purely additive observability /
+ * control over the existing turn (INV-44): `onProgress` streams reduced progress
+ * snapshots out; `signal` cancels the turn in. Neither touches the result path,
+ * and neither pulls `vscode` into this module (INV-43 — `AbortSignal` is a web
+ * standard, the progress snapshot is a domain type).
+ */
+export interface RunEditTurnOptions {
+  modelId?: string;
+  onProgress?: (snapshot: TurnProgressSnapshot) => void;
+  signal?: AbortSignal;
+}
+
 const SYSTEM_PROMPT = [
   "You are a precise text editor embedded in VS Code.",
   "You will be given a piece of text and an instruction.",
@@ -40,7 +56,7 @@ export function extractReplacement(outputText: string, selectedText: string): st
 export async function runEditTurn(
   instruction: string,
   selectedText: string,
-  opts?: { modelId?: string },
+  opts?: RunEditTurnOptions,
 ): Promise<EditTurnResult> {
   const sdk = await import("@cline/sdk");
   const modelId = opts?.modelId ?? "sonnet";
@@ -49,16 +65,50 @@ export async function runEditTurn(
     modelId,
     systemPrompt: SYSTEM_PROMPT,
   });
-  const result = await agent.run(
-    `<instruction>\n${instruction}\n</instruction>\n<text>\n${selectedText}\n</text>`,
-  );
-  // The SDK's AgentRunResult.status union is "completed" | "aborted" | "failed"
-  // (@cline/shared agent.d.ts) — "completed" is the success status.
-  if (result.status !== "completed") {
-    throw new Error(
-      `claude-code turn ${result.status}: ${result.error?.message ?? "unknown error"} ` +
-        "(is Claude Code installed and signed in?)",
+
+  // Stream reduced progress snapshots out (INV-44 additive) and wire cancellation
+  // in via the AbortSignal (INV-47). agent.subscribe returns its unsubscribe fn.
+  let state = createTurnProgressState();
+  const unsubscribe = opts?.onProgress
+    ? agent.subscribe((event) => {
+        const next = reduceTurnProgress(state, event);
+        state = next.state;
+        // Observability must never affect the result (INV-44): a throwing relay
+        // is swallowed, not allowed to propagate into the SDK and fail the turn.
+        if (next.snapshot) {
+          try {
+            opts.onProgress!(next.snapshot);
+          } catch {
+            /* progress is best-effort */
+          }
+        }
+      })
+    : undefined;
+  const onAbort = () => agent.abort();
+  opts?.signal?.addEventListener("abort", onAbort);
+
+  try {
+    // A signal already aborted before the turn starts can't be honored by
+    // agent.abort() (the SDK's AbortController isn't created until run()), so
+    // short-circuit to the same aborted outcome the call site reflects (INV-47).
+    if (opts?.signal?.aborted) {
+      throw new Error("claude-code turn aborted: cancelled before start");
+    }
+    const result = await agent.run(
+      `<instruction>\n${instruction}\n</instruction>\n<text>\n${selectedText}\n</text>`,
     );
+    // The SDK's AgentRunResult.status union is "completed" | "aborted" | "failed"
+    // (@cline/shared agent.d.ts) — "completed" is the success status. An aborted
+    // turn (user cancel) falls into this throw; the call site reflects "cancelled".
+    if (result.status !== "completed") {
+      throw new Error(
+        `claude-code turn ${result.status}: ${result.error?.message ?? "unknown error"} ` +
+          "(is Claude Code installed and signed in?)",
+      );
+    }
+    return { replacement: extractReplacement(result.outputText, selectedText), model: modelId, sessionId: result.runId };
+  } finally {
+    unsubscribe?.();
+    opts?.signal?.removeEventListener("abort", onAbort);
   }
-  return { replacement: extractReplacement(result.outputText, selectedText), model: modelId, sessionId: result.runId };
 }