## Create Session

`$client->beta->sessions->create(Agent agent, string environmentID, ?array<string,string> metadata, ?list<Resource> resources, ?string title, ?list<string> vaultIDs, ?list<AnthropicBeta> betas): BetaManagedAgentsSession`

**post** `/v1/sessions`

Create Session

### Parameters

- `agent: Agent`

  Agent identifier. Accepts the `agent` ID string, which pins the latest version for the session, or an `agent` object with both id and version specified.

- `environmentID: string`

  ID of the `environment` defining the container configuration for this session.

- `metadata?:optional array<string,string>`

  Arbitrary key-value metadata attached to the session. Maximum 16 pairs, keys up to 64 chars, values up to 512 chars.

- `resources?:optional list<Resource>`

  Resources (e.g. repositories, files) to mount into the session's container.

- `title?:optional string`

  Human-readable session title.

- `vaultIDs?:optional list<string>`

  Vault IDs for stored credentials the agent can use during the session.

- `betas?:optional list<AnthropicBeta>`

  Optional header to specify the beta version(s) you want to use.

### Returns

- `BetaManagedAgentsSession`

  - `string id`

  - `BetaManagedAgentsSessionAgent agent`

    Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

  - `?\Datetime archivedAt`

    A timestamp in RFC 3339 format

  - `\Datetime createdAt`

    A timestamp in RFC 3339 format

  - `string environmentID`

  - `array<string,string> metadata`

  - `list<BetaManagedAgentsOutcomeEvaluationResource> outcomeEvaluations`

    Per-outcome evaluation state. One entry per define_outcome event sent to the session.

  - `list<ManagedAgentsSessionResource> resources`

  - `BetaManagedAgentsSessionStats stats`

    Timing statistics for a session.

  - `Status status`

    SessionStatus enum

  - `?string title`

  - `Type type`

  - `\Datetime updatedAt`

    A timestamp in RFC 3339 format

  - `BetaManagedAgentsSessionUsage usage`

    Cumulative token usage for a session across all turns.

  - `list<string> vaultIDs`

    Vault IDs attached to the session at creation. Empty when no vaults were supplied.

  - `?string deploymentID`

    Deployment ID when the session was created from a deployment reference. Null otherwise.

### Example

```php
<?php

require_once dirname(__DIR__) . '/vendor/autoload.php';

$client = new Client(apiKey: 'my-anthropic-api-key');

$betaManagedAgentsSession = $client->beta->sessions->create(
  agent: 'agent_011CZkYpogX7uDKUyvBTophP',
  environmentID: 'env_011CZkZ9X2dpNyB7HsEFoRfW',
  metadata: ['foo' => 'string'],
  resources: [
    [
      'fileID' => 'file_011CNha8iCJcU1wXNR6q4V8w',
      'type' => 'file',
      'mountPath' => '/uploads/receipt.pdf',
    ],
  ],
  title: 'Order #1234 inquiry',
  vaultIDs: ['string'],
  betas: ['message-batches-2024-09-24'],
);

var_dump($betaManagedAgentsSession);
```

#### Response

```json
{
  "id": "sesn_011CZkZAtmR3yMPDzynEDxu7",
  "agent": {
    "id": "agent_011CZkYpogX7uDKUyvBTophP",
    "description": "A general-purpose starter agent.",
    "mcp_servers": [
      {
        "name": "example-mcp",
        "type": "url",
        "url": "https://example-server.modelcontextprotocol.io/sse"
      }
    ],
    "model": {
      "id": "claude-sonnet-4-6",
      "speed": "standard"
    },
    "multiagent": {
      "agents": [
        {
          "id": "agent_011CZkYqphY8vELVzwCUpqiQ",
          "description": "A focused research subagent.",
          "mcp_servers": [
            {
              "name": "example-mcp",
              "type": "url",
              "url": "https://example-server.modelcontextprotocol.io/sse"
            }
          ],
          "model": {
            "id": "claude-sonnet-4-6",
            "speed": "standard"
          },
          "name": "Researcher",
          "skills": [
            {
              "skill_id": "xlsx",
              "type": "anthropic",
              "version": "1"
            }
          ],
          "system": "You are a research subagent that gathers and summarises sources for the coordinating agent.",
          "tools": [
            {
              "configs": [
                {
                  "enabled": true,
                  "name": "bash",
                  "permission_policy": {
                    "type": "always_allow"
                  }
                }
              ],
              "default_config": {
                "enabled": true,
                "permission_policy": {
                  "type": "always_ask"
                }
              },
              "type": "agent_toolset_20260401"
            }
          ],
          "type": "agent",
          "version": 1
        }
      ],
      "type": "coordinator"
    },
    "name": "My First Agent",
    "skills": [
      {
        "skill_id": "xlsx",
        "type": "anthropic",
        "version": "1"
      },
      {
        "skill_id": "skill_011CZkZFNu9hAbo3jZPRgTlx",
        "type": "custom",
        "version": "2"
      }
    ],
    "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": [
      {
        "configs": [
          {
            "enabled": true,
            "name": "bash",
            "permission_policy": {
              "type": "always_allow"
            }
          }
        ],
        "default_config": {
          "enabled": true,
          "permission_policy": {
            "type": "always_ask"
          }
        },
        "type": "agent_toolset_20260401"
      }
    ],
    "type": "agent",
    "version": 1
  },
  "archived_at": null,
  "created_at": "2026-03-15T10:00:00Z",
  "environment_id": "env_011CZkZ9X2dpNyB7HsEFoRfW",
  "metadata": {},
  "outcome_evaluations": [
    {
      "completed_at": "2026-03-15T10:02:31Z",
      "description": "Produce a 2-page summary as summary.md",
      "explanation": "All five sections present with inline citations.",
      "iteration": 0,
      "outcome_id": "outc_011CZkZRSw2kEfs6ncTVljxP",
      "result": "satisfied",
      "type": "outcome_evaluation"
    }
  ],
  "resources": [
    {
      "id": "sesrsc_011CZkZBJq5dWxk9fVLNcPht",
      "created_at": "2026-03-15T10:00:00Z",
      "file_id": "file_011CNha8iCJcU1wXNR6q4V8w",
      "mount_path": "/uploads/receipt.pdf",
      "type": "file",
      "updated_at": "2026-03-15T10:00:00Z"
    },
    {
      "id": "sesrsc_011CZkZCKr6eXyl0gWMOdQiu",
      "created_at": "2026-03-15T10:00:00Z",
      "mount_path": "/workspace/example-repo",
      "type": "github_repository",
      "updated_at": "2026-03-15T10:00:00Z",
      "url": "https://github.com/example-org/example-repo",
      "checkout": {
        "name": "main",
        "type": "branch"
      }
    }
  ],
  "stats": {
    "active_seconds": 0,
    "duration_seconds": 0
  },
  "status": "idle",
  "title": "Order #1234 inquiry",
  "type": "session",
  "updated_at": "2026-03-15T10:00:00Z",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_read_input_tokens": 0,
    "input_tokens": 0,
    "output_tokens": 0
  },
  "vault_ids": [
    "vlt_011CZkZDLs7fYzm1hXNPeRjv"
  ],
  "deployment_id": "deployment_id"
}
```
