Closes anomalyco#3472 ## Problem The VS Code extension claims "Context Awareness" but doesn't actually share editor state with opencode. When users select text in VS Code and refer to it in a prompt, the agent has no idea what they're looking at. There's no indication in the TUI that the IDE is connected or what file/selection is active. ## Solution Add an MCP server to the VS Code extension that exposes the editor's active file and selection as an `editor://context` resource with live push updates. The CLI auto-discovers the server via a lock file protocol, subscribes to context changes, and surfaces the information in three places: 1. **System prompt** — the agent always knows what file the user has open and what text is selected 2. **TUI sidebar** — "Editor" section showing active filename and selected line range, updating in real time as the user navigates 3. **Message history** — `✂ Selected N lines from filename` badge below user messages that had an active selection at submission time ## How it works ``` VS Code extension CLI (opencode) ┌─────────────────────┐ ┌──────────────────────────┐ │ vscode-editor-state │ editor events │ ide/index.ts │ │ (onDidChange*) │───debounce───► │ subscribeToContext() │ │ │ notify │ ├─ readResource() │ │ mcp-server.ts │◄─subscribe─── │ ├─ editorContext() │ │ editor://context │ resource │ └─ Bus → ContextUpdated │ │ resource + notify │ read │ │ └─────────────────────┘ │ session/system.ts │ │ (reads stored state) │ │ │ │ TUI sidebar.tsx │ │ (Editor section) │ │ │ │ TUI index.tsx │ │ (✂ message badges) │ └──────────────────────────┘ ``` **Discovery:** The extension starts an MCP HTTP server on an OS-assigned port, writes a lock file to `{xdgData}/opencode/ide/{port}.lock` containing the auth token and PID, and sets `OPENCODE_MCP_PORT` in the terminal environment. The CLI reads this on startup, verifies the PID is alive, and connects with Bearer auth. **Live updates:** The extension debounces editor events (active file changes, selection changes) at 150ms and sends `notifications/resources/updated`. The CLI re-reads the resource on each notification and publishes a bus event that the TUI sync store picks up via the existing SSE event stream. ## Recommended review order This is a lot of files. They form three layers — reading them in this order builds understanding incrementally. **Layer 1: Extension MCP server (the producer)** Start here to understand the contract everything else depends on. 1. `sdks/vscode/src/mcp-server.ts` — The core: `EditorState` interface, `editor://context` resource, per-session routing, `notifyContextChanged()` broadcast. 2. `sdks/vscode/src/vscode-editor-state.ts` — Production `EditorState` bridging to VS Code APIs. Only file that imports `vscode`. 3. `sdks/vscode/src/extension.ts` — Wiring: server lifecycle, lock file, env var, debounced event listeners. 4. `sdks/vscode/test/mcp-server.test.ts` — Confirms the contract. Reading the tests also documents expected behavior. **Layer 2: CLI subscription and state (the consumer)** Now you know what's produced — here's how the CLI connects and maintains state. 5. `packages/opencode/src/ide/index.ts` — Discovery (lock file, PID check), connection, `subscribeToContext()`, reactive `editorContext()` state. Biggest and most important file on the CLI side. 6. `packages/opencode/src/mcp/index.ts` — One-line change: calls `subscribeToContext` after connect. 7. `packages/opencode/src/session/system.ts` — One-function change: reads from stored state instead of a network call. 8. `packages/opencode/test/ide/` — Integration tests for the full pipeline (resource reads, notifications, discovery). **Layer 3: TUI display (the surface)** Finally, how the stored state reaches the user. 9. `packages/opencode/src/cli/cmd/tui/context/sync.tsx` — Adds `ide_context` to the reactive store. 10. `packages/opencode/src/cli/cmd/tui/routes/session/sidebar.tsx` — Editor section in the sidebar. 11. `packages/opencode/src/cli/cmd/tui/routes/session/index.tsx` — Message context snapshots and ✂ badges. Generated files (`openapi.json`, `types.gen.ts`) and config files (`tsconfig.test.json`, `.gitignore`, `package.json`) are mechanical and can be skimmed. ## Test plan - Extension tests: `cd sdks/vscode && bun test` (9 pass) - Extension compiles: `cd sdks/vscode && bun run compile` - CLI typecheck: `cd packages/opencode && bun run typecheck` - CLI IDE tests: `cd packages/opencode && bun test test/ide/` (25 pass) - Manual E2E: Extension dev host → open file → select text → run opencode → sidebar shows Editor section → submit prompt → ✂ badge appears → switch file → sidebar updates → deselect → line range disappears → close editors → Editor section disappears

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Commits

Commits on Mar 23, 2026

feat: live IDE context awareness