List tree — GET /v1/agent/sessions/{id}/tree

Returns the subagent-flow graph rooted at this session: the session, its children, their children, each node carrying its own event count.

GET /v1/agent/sessions/{id}/tree

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Address	`https://api.hanzo.ai/v1/agent/sessions/{id}/tree`
Method	`GET`
Operation	`get_agent_sessions_by_id_tree`
Auth	`Authorization: Bearer $HANZO_API_KEY`

Returns the subagent-flow graph rooted at this session: the session, its children, their children, each node carrying its own event count. One indexed read pulls the whole flow (every node of a flow shares a root id), so the shape is assembled in memory rather than by walking the store per node. It holds the sessions the caller may see — a member's own, every one for an admin of the org — and a session they may not see is absent with all beneath it.

Request

1 field.

Field	In	Type	Required	Description
`id`	path	string	yes	ID is the session to act on, from the path.

Response

Status	Body	Meaning
`200`	agent.treeNode	ok
`default`	problem-details	refused

200 body — 47 fields.

Field	In	Type	Always	Description
`children`	body	agent.treeNode[]	—	Children is this node's direct children, each a whole node, so the array nests to the depth of the flow.
`session`	body	agent.sessionView	—
`session.account`	body	string	—	Account is which subscription or API account under that provider served it.
`session.actor`	body	string	—	Actor is WHO this session belongs to, as "org/sub" — the same identity a run is billed under.
`session.agent`	body	string	—	Agent is the label the surface running this session calls itself by ("hanzo-dev"), up to 128 characters.
`session.base`	body	string	—	Base is the branch the run started from.
`session.branch`	body	string	—	Branch is the branch the run pushes its work to, and the only one it may write.
`session.children`	body	integer (int64)	—	Children is the DIRECT fan-out — how many sessions name this one as parent — and not the size of the subtree.
`session.createdAt`	body	string	—	CreatedAt is when the row was written, same format.
`session.cwd`	body	string	—	Cwd is the directory the session is working in NOW, not the one it started in: a linked shell moves around, and a card showing where `hanzo link` was run answers "which work is this" with something that was true once.
`session.endedAt`	body	string	—	EndedAt is when it reached done or error, same format.
`session.environment`	body	string	—	Environment is where the run executes: "sandbox" for a Hanzo sandbox, or the id of the org's machine it was routed to (the same id Target carries).
`session.events`	body	integer (int64)	—	Events is how many turns the session's log holds, counted at read time.
`session.host`	body	string	—	Execution context (mission-control): the machine/repo/cwd a card shows and the run-target a session is dispatched to.
`session.id`	body	string	—	ID is the session's handle, minted here as "sess_" + 32 hex characters.
`session.kind`	body	string	—	Kind is what sort of run this session is the view of — "coding" for a coding run.
`session.lastEvent`	body	agent.lastEventView	—
`session.lastEvent.actor`	body	string	—	Actor is who produced the turn, defaulted to the calling principal when the writer named nobody.
`session.lastEvent.at`	body	string	—	At is when the turn was recorded, RFC 3339 in UTC to the second.
`session.lastEvent.kind`	body	string	—	Kind is what the turn was, from the log's closed six: message, tool-call, spawn, log, status, control.
`session.lastEvent.preview`	body	string	—	Preview is the first 240 bytes of the event's payload, cut without regard for the JSON inside it — it is a string to SHOW, never a value to parse.
`session.lastEvent.seq`	body	integer (int64)	—	Seq is that event's position in the session's log — monotonic from 1, per session.
`session.mode`	body	string	—	Mode is what the run may do to its repository: "build" edits, commits and pushes its branch; "plan" reads and answers with a plan, writing nothing.
`session.org`	body	string	—	Org is the caller's OWN tenant, echoed so a client can build the public build URL (/builds/:org/:project) without a second call or a guess.
`session.parentSessionId`	body	string	—	ParentSessionID is the session that spawned this one, making this a subagent of it.
`session.pr`	body	string	—	PR is the address of the pull request the run proposed.
`session.progress`	body	agent.sessionProgress	—
`session.progress.activity`	body	string	—	Activity is the one line saying what the run is doing right now ("running the reaper's tests"), up to 120 characters, in the model's words.
`session.progress.at`	body	string	—	At is when this was determined, RFC 3339 in UTC to the second.
`session.progress.estimated`	body	boolean	—	Estimated says a MODEL produced this, from the run's transcript, and it may be wrong.
`session.progress.pct`	body	integer (int64)	—	Pct is how much of the run is done, 0 to 100.
`session.progress.phase`	body	string	—	Phase is what shape the run is in: running, blocked, done, error, or unknown when nothing has estimated it yet.
`session.project`	body	string	—	The readable build: the product this session built and whether its story is public (provenance.go).
`session.provider`	body	string	—	Provider is the linked AI account's provider (claude \| codex \| hanzo \| …) that served this run.
`session.published`	body	boolean	—	Published is the author's decision to let anyone read this session's story at the public build route.
`session.repo`	body	string	—	Repo is the code the session is working on, as the surface reported it.
`session.room`	body	string	—	Room is the collaborative room this run was started in (HIP-0523), empty when it came from anywhere else — a CLI, a schedule, an API call.
`session.rootSessionId`	body	string	—	RootSessionID is the top of this session's tree, inherited from the parent and shared by every node in one flow.
`session.sandbox`	body	string	—	Sandbox is the id of the sandbox the run works in ("m_" and 24 hex), the handle its terminal and its screen are opened with (/v1/sandbox/{id}/terminal, /screen).
`session.startedAt`	body	string	—	StartedAt is when the session opened, RFC 3339 in UTC to the second.
`session.status`	body	string	—	Status is one of exactly four: running, paused, done, error.
`session.target`	body	string	—	Target is the registered run-target this session is dispatched to — a machine the org claimed, resolved same-org when it was set, so it can never point at another tenant's computer.
`session.taskRunId`	body	string	—	TaskRunID is that workflow's particular run.
`session.taskWorkflowId`	body	string	—	TaskWorkflowID is the hanzoai/tasks durable workflow that actually EXECUTES this session — this registry is the view, control and stream layer over it.
`session.terminal`	body	string	—	Terminal is where this session can be WATCHED — the URL the machine published for its live terminal.
`session.title`	body	string	—	Title is the human line a card shows ("ship the landing page"), up to 512 characters.
`session.updatedAt`	body	string	—	UpdatedAt is the session's last-activity clock, same format.

Failure carries the platform error shape — see Errors.

Examples

CLI

SDK

HTTP

MCP

hanzo agent sessions tree <id>

.ts

.py

.go

.rs

.java

import { Configuration, AgentApi } from 'hanzoai';

const api = new AgentApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.getAgentSessionsByIdTree({ id: 'id' });

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

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = AgentApi(client).get_agent_sessions_by_id_tree(id='id')

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

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

use hanzo_client::apis::{configuration::Configuration, agent_api};

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

let result = agent_api::get_agent_sessions_by_id_tree(&cfg, Default::default()).await?;

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

ApiClient client = new ApiClient();
client.setBearerToken(System.getenv("HANZO_API_KEY"));

var result = new AgentApi(client).getAgentSessionsByIdTree();

curl https://api.hanzo.ai/v1/agent/sessions/<id>/tree \
  -H "Authorization: Bearer $HANZO_API_KEY"

MCP reaches agent through the agent tool, which names its 38 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_agents"
         }
       }
     }'

Agent API · All Hanzo APIs · Interactive reference

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