aiti-opencode-agent

The OpenCode (sst/opencode) CLI session backend extension: see and open opencode historical sessions in All Sessions, and continue chatting in pi-web. The authoritative implementation of session reading still lives in session-manager (lib/agents/opencode.ts — since opencode 1.19.5, new sessions are written only to the single SQLite db ~/.local/share/opencode/opencode.db, the message+part two tables; modern main path + legacy session_message always-empty fallback), while this extension only does the driving.

Mechanism

• Process model: one one-shot process per turn, opencode run -s <sid> --format json <prompt> (the same as aiti-zcode-agent's oneshot); -s continues an existing session
• Streaming: stdout NDJSON part events (step_start/text/tool/step_finish); text is a snapshot taken after the part completes (not token by token), with deltas diffed per-part by prefix
• Cold restore: cwd follows the session's real directory (session-manager services.sessions.parseSession → meta.cwd), and history is backfilled as seed via parseSession (IndexedMessage → pi-shaped toolCall/toolResult) — born with correct semantics (the claude extension once replayed blank history because cwd fell back to process.cwd(); fixed 2026-09-16)
• New sessions: opencode:new-* placeholder; the first turn captures sessionID from the event stream → session_backend_ready rebinds the composite id
• recycle: /session/recycle (shared layer session-recycle.ts); existing handles are upgraded to the current extension code

Capability surface (deliberately narrowed in v1)

The four-piece set prompt / abort / contextUsage / getMessages (followUp deliberately false); models follow opencode's configured default (no setModel/listModels, selector hidden); steer/image attachments are follow-up items.

Authentication

Self-managed by the CLI: ~/.local/share/opencode/auth.json (opencode auth login). When the CLI isn't installed, the provider doesn't register (PATH → ~/.opencode/bin/opencode, overridable with OPENCODE_CLI_PATH).

Relations

• Coexists with aiti-acp-agent's ACP: opencode under the same agentKey (opencode): this extension resolves first at priority 10, and ACP automatically drops to fallback (fail-over)