Start an agent session on an issue

POST/repos/{owner}/{name}/agent-sessions

Give issue, or title and body to open a new issue first; instruction adds to what the session is asked; mode (plan, implement or review) says what kind of work it is. With the workspace’s Anthropic connection (an owner adds it under Integrations), g1t starts a Claude Managed Agents session with that key: g1t’s MCP server attached with a credential for you and this repository only that lasts the session and is kept in a vault on the Anthropic account (never in the prompt), g1t’s skills (work-on-issue, coordinate, fix-integration) next to the account’s own, and the session, its subagents (threads), what they touched and what they reported recorded here as a g1t session (harness claude_managed_agents). Returns session, its session_url on g1t, provider_session_url, and prompt. With handoff true, or without an Anthropic connection when handoff is not false, nothing is started: command is a Claude Code command line, and prompt what to paste, for someone with g1t’s Claude Code plugin, whose session then attaches to the issue as it starts.

Runs on the workspace’s own Anthropic key: g1t runs no model and bills nothing for it. Without an Anthropic connection (or with handoff: true) nothing is started and command is a Claude Code command line to run with g1t’s plugin. See Sessions.

• Authentication: Required. Send an access token as Authorization: Bearer.
• MCP tool: session with action dispatch, and the same inputs
• Scope: An access token needs pull_requests:write.

Path parameters

Name	Type	Required	Description
owner	string	Yes	The workspace that owns the repository.
name	string	Yes	The repository’s name.

Body parameters

Send a JSON object. Names are snake_case, as in responses; the camelCase spelling is accepted too.

Name	Type	Required	Description
issue	integer	No	The issue to work on. Left out, give title (and body) to open one.
title	string	No	Without issue: the title of a new issue to open and work on.
body	string	No	Without issue: the new issue’s description.
instruction	string	No	What to do beyond what the issue says. Up to 4,000 characters.
mode	string	No	What kind of work: plan (say how, change nothing), implement (the default) or review (review its pull request). One of plan, implement, review.
handoff	boolean	No	true for a Claude Code command and prompt to run yourself instead of a session on the workspace’s Anthropic account; false to refuse when there is no Anthropic connection. Left out, a session when the workspace can, else the hand-off.

Example request

curl -X POST https://api.g1t.sh/repos/flagon-io/hello/agent-sessions \
  -H "Authorization: Bearer $G1T_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "issue": 12,
    "mode": "implement",
    "instruction": "Keep the old greeting behind a flag."
  }'

Example response

A successful request answers 200 with:

{
  "issue": 12,
  "session": {
    "id": "ses_01m4c9a8b7c6d5e4f3g2h1j0k9",
    "repo_id": "rep_01m3m5q6p0e2qaw6mmjahk0qrr",
    "issue": 12,
    "pull": null,
    "branch": null,
    "actor": {
      "id": "usr_01kkntcg1eeb98j62xjm7eh09p",
      "username": "syntaqx"
    },
    "harness": "claude_managed_agents",
    "harness_session_id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
    "title": "#12 Make the greeting name the caller",
    "state": "active",
    "head_commit": null,
    "started_at": "2026-10-12T15:10:02.117Z",
    "last_seen_at": "2026-10-12T15:10:02.117Z",
    "ended_at": null,
    "end_reason": null,
    "parent_id": null,
    "agent_type": null,
    "task": null,
    "prompt": null,
    "result": null,
    "model": "claude-opus-5-5",
    "subagents": 0
  },
  "session_url": "https://g1t.sh/syntaqx/hello/work/sessions/ses_01m4c9a8b7c6d5e4f3g2h1j0k9",
  "provider": "anthropic",
  "provider_session_id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "provider_session_url": "https://platform.claude.com/workspaces/default/sessions/sesn_011CZkZAtmR3yMPDzynEDxu7",
  "handoff": false,
  "command": null,
  "prompt": "Work on issue #12 in syntaqx/hello: Make the greeting name the caller.\n\n…"
}

Errors

A failed request answers with one of these statuses and a body like {"error": {"code": "not_found", "message": "Repository not found."}}. See errors.

Status	Code	When
401	unauthenticated	A token is required, or the one sent is not valid.
403	forbidden	The token is valid but not allowed to do this, such as a member-only change, or a token without the scope it needs.
404	not_found	It does not exist, or you cannot see it.
409	conflict	The request conflicts with the current state.
422	invalid	The input is not valid. message says which field and why.