Mission Control

Agents run from everywhere: the CLI, the console, chat, a bot. Mission Control is the one place all of them show up, live, with the controls to intervene.

Open it at console.hanzo.ai → Mission Control. It is a view over the agent session plane, so everything below is available over the API too.

What a session is

A session is the org-scoped row every surface hangs its activity off. It carries an append-only event log with a monotonic seq, and sessions form a tree: a session with a parentSessionId is a subagent and inherits the parent's rootSessionId, so one piece of work is one tree no matter how many agents it spawns.

Status is running, paused, done, or error. Events are one of message, tool-call, spawn, log, status, or control. A session also records where it is running: agent, host, cwd, repo, and target.

List what is running

curl "https://api.hanzo.ai/v1/agents/sessions?status=running&limit=50" \
  -H "Authorization: Bearer $HANZO_API_KEY"

Roots only by default. Pass ?parent= or ?root= to walk into a tree, or ?project= to scope it. limit defaults to 100 and caps at 500.

GET /v1/agents/sessions/{id} returns one session with its direct children and its 50 most recent events; /tree returns the whole tree; and GET /v1/agents/sessions/stream is a server-sent event stream of session and event frames with a keepalive every 25 seconds.

The four controls

# Ask a session to pause
curl -X POST https://api.hanzo.ai/v1/agents/sessions/$ID/pause \
  -H "Authorization: Bearer $HANZO_API_KEY"

# Send it a message mid-run
curl -X POST https://api.hanzo.ai/v1/agents/sessions/$ID/message \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "message": "skip the migration, just report" }'

resume and stop are the same shape as pause. All four answer { command, event, forwarded }.

A control command is an intent, not a state change. This is the one thing to get right. A 200 means the command was durably recorded and delivered — not that the agent has paused. The status becomes paused, done, or error only when the surface actually running the agent reports it back with PATCH /v1/agents/sessions/{id}. An agent in the middle of a long tool call notices its next checkpoint, not your request.

Delivery works by the running surface draining GET /v1/agents/sessions/{id}/control?after={seq} — which is why forwarded is false: the command is waiting to be picked up, and that is normal.

Three more rules worth knowing:

• stop is the blunt one. For a session backed by a durable workflow it cancels rather than signals; any message you send with it becomes the cancellation reason.
• message is the only command with a required body — message (up to 16 KiB) or payload. Neither is a 400.
• A finished session refuses every command with 409. A session id another org owns answers 404, exactly like one that never existed.

Related

• Agents — defining and running the agents that open these sessions
• Automations — durable flows, including steps that wait for a person
• Traces — the recorded execution behind a run
• API Reference — every endpoint at api.hanzo.ai