[som4tress]

Fixes #117.

Problem

Tapping OpenCode in the app always failed against an OpenCode v2.x server. Three separate v2 incompatibilities were involved.

1. Ready-line banner (the 15s timeout)

createOpencodeServer() from the bundled @opencode-ai/sdk@1.18.18 waits for a stdout line starting with opencode server listening:

if (line.startsWith("opencode server listening")) { ... }

OpenCode v2 prints server listening on http://127.0.0.1:40201 instead, so the match never fires and the SDK kills the server after timeout ms, surfacing as:

Timeout waiting for server to start after 15000ms

2. Per-server password

v2 generates a password per server. The CLI built its client with a random Basic header (Basic base64(shellular:<random32>)) that v2 rejects with 401, and never read the printed password.

3. Session list endpoint returns HTML

experimental.session.list requests /experimental/session. On v2.1.4 that path serves the web UI:

$ curl -i -H "Authorization: Basic ..." http://127.0.0.1:49374/experimental/session
HTTP/1.1 200
content-type: text/html

so the SDK's response interceptor throws:

Request is not supported by this version of OpenCode Server (Server responded with text/html)

The real JSON API is at /api/session:

$ curl -i -H "Authorization: Basic ..." http://127.0.0.1:49374/api/session
HTTP/1.1 200
content-type: application/json

The v2 payload also differs in shape from what the app expects: directory lives under location.directory, and slug/version/project are absent.

Changes

All in cli/src/agents/opencode.ts:

• Reuse a running server instead of depending on the v1 banner. Resolution order: OPENCODE_SERVER_URL → default port 4096 probe → ~/.config/opencode/service.json (written by opencode serve --service). Discovered servers are marked external and are never killed in destroy(); only servers we spawn are closed.
• Use the real password from service.json for Basic auth instead of a random one.
• Fall back to /api/session when the SDK call fails, and normalize the v2 response into the v1 shape: directory from location.directory, slug derived from the title when missing, version from /api/info, project reconstructed from projectID + directory. v1-shaped payloads pass through unchanged, so older servers keep working.

Verification

Against OpenCode v2.1.4 on Linux, paired with the iOS app (0.0.43):

• tsc --noEmit clean
• biome check clean
• pnpm run build succeeds
• In the app: pairing succeeds, OpenCode connects to the already-running server, and the session list loads instead of erroring.

  ✓ Client c_... connected
  reusing running opencode server at http://127.0.0.1:49374

Note the server was already running as a background service, so the spawn path (and therefore the banner fix itself) is not exercised here — it remains the fallback when no server is discoverable.