# vscode-cowriting-plugin

Non-shippable **proof-of-concept** (Feature #2 of Epic #1): a standalone VS Code
extension that drives **[`@cline/sdk`](https://www.npmjs.com/package/@cline/sdk)**
— validating Approach A (own coauthoring extension on the Cline SDK, no fork).

## What it does

Registers one command, **`Cowriting: Show Cline SDK Info`**, which loads
`@cline/sdk` and shows the SDK build version plus the agent's builtin tool
catalog (a pure, key-free SDK call) in a notification and the
"Cowriting (Cline SDK)" output channel.

Features shipped so far: F2 region-anchored threads (Feature #4), F3 live
human/Claude attribution (Feature #6), F4 propose/accept diff flow
(Feature #12).

## Architecture

- CommonJS extension bundled with esbuild (`src/extension.ts` → `out/extension.cjs`).
- `@cline/sdk` is ESM-only (Node ≥22) and uses `createRequire(import.meta.url)`,
  so it is **not** bundled — it is shipped in `node_modules` and loaded at
  runtime via dynamic `import()` from the vscode-free `src/cline.ts`.

## Run it (F5)

1. `npm install`
2. `npm run build`
3. Press **F5** (or Run → "Run Extension") to launch the Extension Development Host.
   It opens the committed **`sandbox/`** playground as its workspace (not the
   repo itself — VS Code won't open one folder in two windows, #8); start with
   `sandbox/playground.md`.
4. In the new window: **Cmd/Ctrl+Shift+P** → **"Cowriting: Show Cline SDK Info"**.

## F2 — Region-anchored threads (Feature #4)

Attach durable, region-anchored discussion threads to any document. Threads
render in the native VS Code **Comments** gutter and persist as git-native
sidecars under `.threads/<doc-path>.json` (plain, diffable JSON — no server).

- **Create:** select text → run **"Cowriting: Add Coauthoring Thread on Selection"**
  (or the Comments gutter "+").
- **Reply / Resolve:** use the native Comments reply box and the thread's
  Resolve/Reopen actions.
- **Survives edits, reload, and external change (`git pull`):** a hybrid anchor
  (durable content fingerprint + live offset tracking) re-resolves the thread.
  If the anchored text can't be confidently re-found, the thread is shown as
  **orphaned** at its last-known line — never silently moved.

Design: `vscode-cowriting-plugin-content/specs/coauthoring-inner-loop.md`. No live
`@cline/sdk` turn and no credentials are involved in F2.

## F3 — Live human/Claude attribution (Feature #6)

As you and Claude coauthor, every span in the buffer carries an author: human
edits render with a subtle left border, Claude-authored spans with a background
tint. Text that predates tracking stays plain — the honest record. Edits that
touch a boundary (split, merge, partial overwrite) are handled char-precisely.

Attribution is persisted git-natively in the same `.threads/` sidecars
(`attributions[]`, sharing the same `anchors` fingerprints as F2 threads). On
reload, fingerprints re-resolve spans against the current document; spans that
can't be confidently re-found are **orphaned** (status-bar count + "Cowriting
Attribution" output channel) rather than silently moved or discarded.

**Commands**

- **`Cowriting: Ask Claude to Edit Selection`** — select text → enter an
  instruction → a live `@cline/sdk` turn runs on the built-in `claude-code`
  provider (rides your local Claude Code Pro/Max login; the extension stores no
  credentials). As of F4 the turn ends in a **proposal** (see below); accepted
  text lands as a Claude-attributed span.
- **`Cowriting: Toggle Attribution`** — show/hide attribution decorations.
- `cowriting.applyAgentEdit` _(palette-hidden)_ — the single machine-edit
  ingress seam. Tests drive this directly so CI requires no LLM.

Design: `vscode-cowriting-plugin-content/specs/coauthoring-attribution.md`.

## F4 — Propose/accept diff flow (Feature #12)

Claude's edits arrive as **pending proposals** — propose-by-default, the
document never changes without your say-so. A proposal renders two ways at
once: an **amber tint** on the target range, and a "Claude proposes" comment
thread showing a fenced `diff` of current → proposed text with two actions:

- **✓ Accept Proposal** — applies the replacement through the `applyAgentEdit`
  seam, so it lands Claude-attributed (F3) — and the proposal disappears.
- **✗ Reject Proposal** — the document is untouched; the proposal disappears.

Pending proposals persist git-natively in the same sidecar (`proposals[]`,
sharing the F2/F3 `anchors` fingerprints), survive reload, and re-anchor as
surrounding text changes. If the **target text itself** changes, the proposal
goes **stale** (status-bar count, accept disabled — never applied by guess);
undo the change and it becomes decidable again. `cowriting.proposeAgentEdit`
_(palette-hidden)_ is the programmatic propose ingress E2E drives — no LLM in
CI.

Design: `vscode-cowriting-plugin-content/specs/coauthoring-propose-accept.md`.
Live smoke: [`docs/MANUAL-SMOKE-F4.md`](docs/MANUAL-SMOKE-F4.md).

## Develop

- `npm run watch` — rebuild on change.
- `npx vitest run` — unit suite (SDK driver, schema, store, anchorer, thread
  mutations, attribution split/merge).
- `npm run test:e2e` — `@vscode/test-electron` host E2E
  (create → reply → resolve → persist → reload → re-anchor → orphan; drives
  `cowriting.applyAgentEdit` directly — no LLM required).
- `npm run smoke:live` — scripted live-turn smoke test for F3; requires Claude
  Code installed and signed in. See
  [`docs/MANUAL-SMOKE-F3.md`](docs/MANUAL-SMOKE-F3.md).
- `npm run typecheck` — type-check without emit.