Local protocol

Cohorte exposes JSON-RPC 2.0 using protocol cohorte/1. The implemented bridge is cohorte rpc --stdio: UTF-8 JSON Lines, one frame per line, with a 1 MiB frame limit. Clients must call initialize first.

Implemented methods: health.get, projects.list/get/init, accounts.list/status, features.list/get, runs.start/get/list/export/pause/resume/cancel, requests.list/respond, artifacts.get, metrics.get, and events.subscribe/unsubscribe. Mutations require a deduplication identifier. Reusing it with different content is rejected. Events are durable and replayed by sequence. Account methods expose passive official-client status and never credentials.

runs.export returns the run state and its durable events, requests, approvals, tasks, attempts, sessions, findings, checks, and effects. The RPC export defaults to 512 KiB and cannot exceed 768 KiB, leaving space below the 1 MiB frame limit. cohorte export RUN_ID --output FILE provides the same redacted document with an atomic file replacement and a configurable 1 KiB to 50 MiB limit. Check output is capped at 256 KiB. Secret-shaped keys, inline assignments, and bearer credentials are redacted before durable log writes and again at CLI and protocol boundaries.

On POSIX, cohorte service start hosts the same protocol on a Unix socket inside the private data directory. The directory is mode 0700, the socket and service identity are 0600, and the host requires the peer UID to match the service UID (LOCAL_PEERCRED on macOS, SO_PEERCRED where available). service status performs a real protocol health call and service stop uses a deduplicated RPC shutdown instead of signaling an unverified PID. Each connection has its own handshake state; disconnecting a client does not change workflow state. On the socket, events.subscribe returns the durable replay and watermark, then emits events.notification frames for later events. A bounded writer timeout disconnects a slow client; it resumes from its last processed sequence. Replay responses are capped below the transport frame limit and individual event payloads cannot exceed 512 KiB. The equivalent Windows live-follow behavior remains a later gate.

The Windows backend is implemented with pywin32: a deterministic local named pipe, remote-client rejection, a DACL containing only the current user SID, and a per-user-session mutex preventing a second service instance. It shares the same JSON-RPC dispatcher and lifecycle commands. Its runtime test passes on GitHub-hosted Windows with Python 3.12 and 3.13; this is CI lifecycle evidence rather than a complete Windows release-support claim. Live follow is withheld from the Windows capability list until asynchronous slow-writer behavior is validated on a real Windows host.

Success confirms acceptance of a mutation. It does not claim that a run or external effect has finished. Structured errors include a stable code, impact, retryability, and remediation.