Stop sessions

Ends a running session. `message` is recorded as the cancellation reason, which is what a later reader of the transcript sees.

POST /v1/agents/sessions/{id}/stop

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Address	`https://api.hanzo.ai/v1/agents/sessions/{id}/stop`
Method	`POST`
Operation	`post_agents_sessions_by_id_stop`
Auth	`Authorization: Bearer $HANZO_API_KEY`

Ends a running session. message is recorded as the cancellation reason, which is what a later reader of the transcript sees.

STOPPING IS NOT DELETING: the session, its transcript and anything it produced stay readable. A session that has already finished is 409 rather than a second stop.

Request

4 fields, body application/json (required).

Field	In	Type	Required	Description
`id`	path	string	yes	ID is the session to steer, from the path.
`id`	body	string	—	ID is the session to steer, from the path.
`message`	body	string	—	Message is free text for the running agent, up to 16 KiB.
`payload`	body	any	—	Payload is a structured argument for the command: any valid JSON up to 64 KiB, scanned for credentials before it is stored (a hit refuses the command with 422…

Response

Status	Body	Meaning
`200`	controlResult	ok

200 body — 10 fields.

Field	In	Type	Always	Description
`command`	body	string	—	Command is the verb that was recorded: pause, resume, stop or message.
`event`	body	eventView	—
`event.actor`	body	string	—	Actor is who produced the turn.
`event.createdAt`	body	string	—	CreatedAt is when the turn was recorded, RFC 3339 in UTC to the second.
`event.id`	body	string	—	ID is the event's own handle, minted as "evt_" + 32 hex characters.
`event.kind`	body	string	—	Kind is what the turn IS, from a closed six: message (a model turn), tool-call, spawn (a subagent started), log, status, control (a steering command the…
`event.payload`	body	any	—	Payload is the turn's body, embedded as JSON rather than as a string — whatever the writer sent, up to 64 KiB, checked for well-formedness and scanned for…
`event.seq`	body	integer	—	Seq is the turn's position in this session's log: monotonic from 1, assigned by the store inside the insert, and unique PER SESSION rather than globally.
`event.sessionId`	body	string	—	SessionID is the session this turn belongs to.
`forwarded`	body	boolean	—	Forwarded is whether the command also reached the durable-execution engine.

Failure carries the platform error shape — see Errors.

Examples

hanzo agents sessions stop <id>

import { Configuration, AgentsApi } from 'hanzoai';

const api = new AgentsApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.postAgentsSessionsByIdStop({ id: 'id', id: "<id>", message: "<message>" });

from hanzoai.cloud import ApiClient, Configuration
from hanzoai.cloud.api import AgentsApi

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = AgentsApi(client).post_agents_sessions_by_id_stop(id='id', id="<id>", message="<message>")

cfg := cloud.NewConfiguration()
cfg.AddDefaultHeader("Authorization", "Bearer "+os.Getenv("HANZO_API_KEY"))
client := cloud.NewAPIClient(cfg)

resp, _, err := client.AgentsAPI.PostAgentsSessionsByIdStop(context.Background()).Execute()
if err != nil {
	return err
}

use hanzo_cloud::apis::{configuration::Configuration, agents_api};

let mut cfg = Configuration::new();
cfg.bearer_access_token = std::env::var("HANZO_API_KEY").ok();

let result = agents_api::post_agents_sessions_by_id_stop(&cfg, Default::default()).await?;

import ai.hanzo.cloud.ApiClient;
import ai.hanzo.cloud.api.AgentsApi;

ApiClient client = new ApiClient();
client.setRequestInterceptor(b -> b.header("Authorization", "Bearer " + System.getenv("HANZO_API_KEY")));

var result = new AgentsApi(client).postAgentsSessionsByIdStop();

curl -X POST https://api.hanzo.ai/v1/agents/sessions/<id>/stop \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "id": "<id>",
       "message": "<message>"
     }'

MCP reaches agents through the agents tool, which names its 36 operations with its own verbs — this one among them, under a name only MCP declares. describe explains any of them:

curl -X POST https://api.hanzo.ai/v1/mcp \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "describe",
         "arguments": {
           "op": "list_agent_conversations"
         }
       }
     }'

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