F3 SLICE-5: live claude-code turn via applyAgentEdit seam + manual smoke (INV-8) (#6)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/MANUAL-SMOKE-F3.md

@@ -0,0 +1,42 @@
+# F3 manual smoke — live `claude-code` turn (spec §6.8)
+
+The live turn is deliberately NOT in CI (unit + host E2E drive the seam). It
+gets this documented smoke, run once per machine that has Claude Code
+installed and signed in (Pro/Max). The extension itself holds no credentials
+(INV-8) — auth is entirely the local Claude Code login.
+
+## 1. Scripted smoke (the quick check)
+
+    npm run smoke:live
+
+Expected: prints a `replacement:` line containing "The smoke test passed.",
+the model id, a non-empty `sessionId`, and exits 0.
+
+## 2. In-editor smoke (the real PUC-2)
+
+1. `npm run build`, then F5 (Extension Development Host) opening this repo.
+2. Open any markdown file in the workspace; type a sentence — it renders with
+   the human gutter border (left edge) as you type.
+3. Select the sentence → run **“Cowriting: Ask Claude to Edit Selection”** →
+   instruction: `rewrite this more formally`.
+4. Expected: progress notification; on completion the replacement text lands
+   **tinted** (Claude-attributed), the human border remains on your other
+   edits, and after **save** the sidecar
+   `.threads/<doc>.json` has an `attributions[]` entry with
+   `author.kind: "agent"`, `agent.model`, `agent.sessionId`, and a `turnId`.
+5. **Cowriting: Toggle Attribution** hides/shows both decorations (PUC-5).
+
+## 3. Failure paths (INV-8 — graceful, tracking unaffected)
+
+- Signed out / no Claude Code: `PATH="" npm run smoke:live` (or sign out) →
+  the script exits 1 with a clear error; in-editor, the command shows an
+  error notification and NO edit is applied.
+- Buffer edited mid-turn: start an edit-selection turn, type elsewhere in the
+  document before it completes → warning notification "document changed", no
+  partial application (stale `expectedVersion`, spec §6.9).
+
+## Smoke log
+
+| Date | Machine | Result |
+| --- | --- | --- |
+| 2026-06-10 | benstull mac (darwin) | PASS — `replacement: "The smoke test passed."`, model `sonnet`, sessionId `run_g_rYKGYl`, 6.9s, exit 0. Failure-path note: with `PATH="/usr/bin:/bin"` the turn STILL succeeded (6.2s) — the SDK resolves `claude` via an absolute path (`~/.local/bin/claude`), not PATH, so a stripped PATH does not exercise the signed-out error; sign out of Claude Code to exercise it for real. |

esbuild.mjs

@@ -17,11 +17,26 @@ const options = {
   logLevel: "info",
 };
 
+/** @type {import('esbuild').BuildOptions} */
+const liveTurnOptions = {
+  entryPoints: ["src/liveTurn.ts"],
+  outfile: "out/liveTurn.mjs",
+  bundle: true,
+  platform: "node",
+  format: "esm",
+  target: "node22",
+  sourcemap: true,
+  external: ["vscode", "@cline/sdk"],
+  logLevel: "info",
+};
+
 if (watch) {
   const ctx = await context(options);
-  await ctx.watch();
+  const ctxLive = await context(liveTurnOptions);
+  await Promise.all([ctx.watch(), ctxLive.watch()]);
   console.log("esbuild: watching…");
 } else {
   await build(options);
-  console.log("esbuild: build complete → out/extension.cjs");
+  await build(liveTurnOptions);
+  console.log("esbuild: build complete → out/extension.cjs + out/liveTurn.mjs");
 }

package.json

@@ -29,7 +29,8 @@
       { "command": "cowriting.resolveThread", "title": "Resolve Thread", "category": "Cowriting" },
       { "command": "cowriting.reopenThread", "title": "Reopen Thread", "category": "Cowriting" },
       { "command": "cowriting.toggleAttribution", "title": "Toggle Attribution", "category": "Cowriting" },
-      { "command": "cowriting.applyAgentEdit", "title": "Apply Agent Edit (internal seam)", "category": "Cowriting" }
+      { "command": "cowriting.applyAgentEdit", "title": "Apply Agent Edit (internal seam)", "category": "Cowriting" },
+      { "command": "cowriting.editSelection", "title": "Ask Claude to Edit Selection", "category": "Cowriting" }
     ],
     "menus": {
       "commandPalette": [
@@ -59,6 +60,7 @@
     "test": "vitest run",
     "pretest:e2e": "npm run build && tsc -p tsconfig.e2e.json",
     "test:e2e": "node ./out/test/e2e/runTest.js",
+    "smoke:live": "npm run build && node scripts/smoke-live-turn.mjs",
     "vscode:prepublish": "node esbuild.mjs"
   },
   "dependencies": {

scripts/smoke-live-turn.mjs

@@ -0,0 +1,22 @@
+#!/usr/bin/env node
+// Scripted half of the F3 manual smoke (docs/MANUAL-SMOKE-F3.md). Drives the
+// REAL LiveTurn module against the local Claude Code login. Not run in CI.
+import { runEditTurn } from "../out/liveTurn.mjs";
+
+const instruction = process.argv[2] ?? "Replace this sentence with exactly: The smoke test passed.";
+const text = process.argv[3] ?? "This sentence is the smoke-test input.";
+
+console.log(`instruction: ${instruction}`);
+console.log(`text:        ${text}`);
+try {
+  const t0 = Date.now();
+  const result = await runEditTurn(instruction, text);
+  console.log(`replacement: ${JSON.stringify(result.replacement)}`);
+  console.log(`model:       ${result.model}`);
+  console.log(`sessionId:   ${result.sessionId}`);
+  console.log(`elapsed:     ${((Date.now() - t0) / 1000).toFixed(1)}s`);
+  process.exit(0);
+} catch (err) {
+  console.error(`live turn failed (expected when Claude Code is absent/signed out): ${err.message}`);
+  process.exit(1);
+}

src/extension.ts

@@ -81,6 +81,56 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
     ),
   );
 
+  // F3 SLICE-5: the live turn (PUC-2) — selection + instruction → one
+  // claude-code SDK turn (liveTurn.ts, INV-8) → the applyAgentEdit seam (INV-9).
+  context.subscriptions.push(
+    vscode.commands.registerCommand("cowriting.editSelection", async () => {
+      const editor = vscode.window.activeTextEditor;
+      if (!editor || editor.selection.isEmpty || !editor.document.uri.fsPath.startsWith(root)) {
+        void vscode.window.showWarningMessage("Cowriting: select some text in a workspace document first.");
+        return;
+      }
+      const instruction = await vscode.window.showInputBox({
+        prompt: "What should Claude do with the selection?",
+        placeHolder: "e.g. tighten this paragraph",
+      });
+      if (!instruction) return;
+      const document = editor.document;
+      const selection = editor.selection;
+      const expectedVersion = document.version;
+      const selectedText = document.getText(selection);
+      const turnId = `turn-${Date.now().toString(36)}`;
+      try {
+        await vscode.window.withProgress(
+          { location: vscode.ProgressLocation.Notification, title: "Cowriting: asking Claude…" },
+          async () => {
+            const { runEditTurn } = await import("./liveTurn");
+            const turn = await runEditTurn(instruction, selectedText);
+            const ok = await attributionController.applyAgentEdit(
+              document,
+              new vscode.Range(selection.start, selection.end),
+              turn.replacement,
+              {
+                kind: "agent",
+                id: "claude",
+                agent: { sdk: "@cline/sdk", model: turn.model, sessionId: turn.sessionId },
+              },
+              { expectedVersion, turnId },
+            );
+            if (!ok) {
+              void vscode.window.showWarningMessage(
+                "Cowriting: the document changed while Claude was editing — nothing was applied.",
+              );
+            }
+          },
+        );
+      } catch (err) {
+        const message = err instanceof Error ? err.message : String(err);
+        void vscode.window.showErrorMessage(`Cowriting: Claude edit failed — ${message}`);
+      }
+    }),
+  );
+
   // Render threads + attributions for already-open editors, and on future opens.
   const renderIfOpen = (doc: vscode.TextDocument) => {
     if (doc.uri.scheme === "file" && doc.uri.fsPath.startsWith(root)) {

src/liveTurn.ts

@@ -0,0 +1,57 @@
+/**
+ * LiveTurn — the minimal machine-edit ingress (spec §6.2): one @cline/sdk
+ * Agent turn on the built-in `claude-code` provider, which rides the
+ * operator's local Claude Code Pro/Max login — the extension holds NO
+ * credentials of any kind (INV-8). vscode-free; the editSelection command
+ * (extension.ts) feeds the result into the applyAgentEdit seam (INV-9).
+ *
+ * Like src/cline.ts: @cline/sdk is ESM-only, loaded via dynamic import(),
+ * never bundled (esbuild keeps it external).
+ */
+
+export interface EditTurnResult {
+  replacement: string;
+  model: string;
+  /** the SDK run id — recorded as provenance sessionId. */
+  sessionId: string;
+}
+
+const SYSTEM_PROMPT = [
+  "You are a precise text editor embedded in VS Code.",
+  "You will be given a piece of text and an instruction.",
+  "Respond with ONLY the edited replacement text — no explanation, no preamble,",
+  "no markdown code fences. Preserve the original's leading/trailing whitespace",
+  "unless the instruction says otherwise.",
+].join(" ");
+
+/** Strip a wrapping markdown code fence if the model added one anyway. */
+export function extractReplacement(outputText: string): string {
+  const m = outputText.match(/^\s*```[^\n]*\n([\s\S]*?)\n?```\s*$/);
+  return m ? m[1] : outputText;
+}
+
+export async function runEditTurn(
+  instruction: string,
+  selectedText: string,
+  opts?: { modelId?: string },
+): Promise<EditTurnResult> {
+  const sdk = await import("@cline/sdk");
+  const modelId = opts?.modelId ?? "sonnet";
+  const agent = new sdk.Agent({
+    providerId: "claude-code",
+    modelId,
+    systemPrompt: SYSTEM_PROMPT,
+  });
+  const result = await agent.run(
+    `<instruction>\n${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?)",
+    );
+  }
+  return { replacement: extractReplacement(result.outputText), model: modelId, sessionId: result.runId };
+}

test/liveTurn.test.ts

@@ -0,0 +1,18 @@
+import { describe, it, expect } from "vitest";
+import { extractReplacement } from "../src/liveTurn";
+
+describe("extractReplacement", () => {
+  it("returns plain text untouched", () => {
+    expect(extractReplacement("Hello world.")).toBe("Hello world.");
+  });
+  it("strips a wrapping fence", () => {
+    expect(extractReplacement("```\nHello world.\n```")).toBe("Hello world.");
+  });
+  it("strips a language-tagged fence", () => {
+    expect(extractReplacement("```markdown\nHello.\n```\n")).toBe("Hello.");
+  });
+  it("leaves inner fences alone", () => {
+    const inner = "before\n```js\ncode\n```\nafter";
+    expect(extractReplacement(inner)).toBe(inner);
+  });
+});