POST
POST /v1/sessions/{session_id}?beta=true — Claude API
Beta
Anthropic API key (required); https://api.anthropic.com
Claude APIUpdate Session
- Base URL
- https://api.anthropic.com
- Auth
- x-api-key: <ANTHROPIC_API_KEY>
- Last verified
- 2026-10-20 · upstream hash matched
Actions Try in browser→
Agents: curl -H "Accept: text/markdown" this URL
→ 312 tokens · Vary: Accept
→ 312 tokens · Vary: Accept
Critical gotchas
Authentication uses the x-api-key header and requests also require an anthropic-version header.
The official OpenAPI URL is discovered from the SDK repository manifest and must remain under Anthropic's trusted Stainless storage prefix.
cURL
curl -X POST 'https://api.anthropic.com/v1/sessions/session-id?beta=true' \ -H "x-api-key: $ANTHROPIC_API_KEY" \ -H 'anthropic-version: 2023-06-01' \ -H 'Content-Type: application/json' \ -d '{}'
Parameters
| Name | In | Type | Required | Description |
|---|---|---|---|---|
| session_id | path | string | Yes | Path parameter session_id |
| title | body | string | No | Human-readable session title. |
| metadata | body | object | No | Metadata patch. Set a key to a string to upsert it, or to null to delete it. Omit the field to preserve. |
| vault_ids | body | string[] | No | Vault IDs (`vlt_*`) to attach to the session. Not yet supported; requests setting this field are rejected. Reserved for future use. |
| agent | body | object | No | Agent configuration update. Only `tools` and `mcp_servers` are updatable mid-session. Only valid for sessions created from an agent or deployment reference. The session must not be running. |
| budget | body | object | No | Enforced spend ceiling for the session. Set an object to replace the budget of a session that was created with one, or `null` to remove it; omit to preserve. A budget cannot be added to a session created without one (rejected with reason `budget_create_only`), and a removed budget cannot be re-added. Allowed in any non-terminated status. Lowering `max_list_cost` to at or below the session's consumed list cost is rejected with reason `budget_not_raised`, and every model the session can run must have a public list price or the request is rejected with reason `model_not_budgetable`. |
Response 200 OK
{
"type": "session",
"id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
"status": "idle",
"created_at": "2026-03-15T10:00:00Z",
"updated_at": "2026-03-15T10:00:00Z",
"archived_at": null,
"budget": null,
"environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
"title": "Order #1234 inquiry",
"metadata": {},
"agent": {
"type": "agent",
"id": "agent_011CZkYpogX7uDKUyvBTophP",
"version": 1,
"name": "My First Agent",
"description": "A general-purpose starter agent.",
"model": {
"id": "claude-opus-5",
"speed": "standard"
},
"system": "You are a general-purpose agent that can research, write code, run commands, and use connected tools to complete the user's task end to end.",
"tools": [
{
"type": "agent_toolset_20260401",
"default_config": {
"enabled": true,
"permission_policy": {
"type": "always_ask"
}
},
"configs": []
}
],
"mcp_servers": [
{
"type": "url",
"name": "example-mcp",
"url": "https://example-server.modelcontextprotocol.io/sse"
}
],
"skills": [
{
"type": "anthropic",
"skill_id": "xlsx",
"version": "1"
},
{
"type": "custom",
"skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
"version": "2"
}
],
"multiagent": null
},
"resources": [
{
"type": "file",
"id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
"file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
"mount_path": "/uploads/receipt.pdf",
"created_at": "2026-03-15T10:00:00Z",
"updated_at": "2026-03-15T10:00:00Z"
},
{
"type": "github_repository",
"id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
"url": "https://github.com/example-org/example-repo",
"mount_path": "/workspace/example-repo",
"checkout": {
"type": "branch",
"name": "main"
},
"created_at": "2026-03-15T10:00:00Z",
"updated_at": "2026-03-15T10:00:00Z"
}
],
"vault_ids": [
"vlt_011CZkZDLs7fYzm1hXNPeRjv"
],
"usage": {
"input_tokens": 0,
"output_tokens": 0,
"cache_read_input_tokens": 0
},
"stats": {
"duration_seconds": 0,
"active_seconds": 0
},
"outcome_evaluations": [
{
"type": "outcome_evaluation",
"outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
"description": "Produce a 2-page summary as summary.md",
"result": "satisfied",
"iteration": 0,
"completed_at": "2026-03-15T10:02:31Z",
"explanation": "All five sections present with inline citations."
}
]
} Get a free Claude API key → sponsored Affiliate link - we may earn a commission, at no extra cost to you.