## Add Session Resource

`beta.sessions.resources.add(strsession_id, ResourceAddParams**kwargs)  -> BetaManagedAgentsFileResource`

**post** `/v1/sessions/{session_id}/resources`

Add Session Resource

### Parameters

- `session_id: str`

- `file_id: str`

  ID of a previously uploaded file.

- `type: Literal["file"]`

  - `"file"`

- `mount_path: Optional[str]`

  Mount path in the container. Defaults to `/mnt/session/uploads/<file_id>`.

- `betas: Optional[List[AnthropicBetaParam]]`

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

  - `str`

  - `Literal["message-batches-2024-09-24", "prompt-caching-2024-07-31", "computer-use-2024-10-22", 23 more]`

    - `"message-batches-2024-09-24"`

    - `"prompt-caching-2024-07-31"`

    - `"computer-use-2024-10-22"`

    - `"computer-use-2025-01-24"`

    - `"pdfs-2024-09-25"`

    - `"token-counting-2024-11-01"`

    - `"token-efficient-tools-2025-02-19"`

    - `"output-128k-2025-02-19"`

    - `"files-api-2025-04-14"`

    - `"mcp-client-2025-04-04"`

    - `"mcp-client-2025-11-20"`

    - `"dev-full-thinking-2025-05-14"`

    - `"interleaved-thinking-2025-05-14"`

    - `"code-execution-2025-05-22"`

    - `"extended-cache-ttl-2025-04-11"`

    - `"context-1m-2025-08-07"`

    - `"context-management-2025-06-27"`

    - `"model-context-window-exceeded-2025-08-26"`

    - `"skills-2025-10-02"`

    - `"fast-mode-2026-02-01"`

    - `"output-300k-2026-03-24"`

    - `"user-profiles-2026-03-24"`

    - `"advisor-tool-2026-03-01"`

    - `"managed-agents-2026-04-01"`

    - `"cache-diagnosis-2026-04-07"`

    - `"thinking-token-count-2026-05-13"`

### Returns

- `class BetaManagedAgentsFileResource: …`

  - `id: str`

  - `created_at: datetime`

    A timestamp in RFC 3339 format

  - `file_id: str`

  - `mount_path: str`

  - `type: Literal["file"]`

    - `"file"`

  - `updated_at: datetime`

    A timestamp in RFC 3339 format

### Example

```python
import os
from anthropic import Anthropic

client = Anthropic(
    api_key=os.environ.get("ANTHROPIC_API_KEY"),  # This is the default and can be omitted
)
beta_managed_agents_file_resource = client.beta.sessions.resources.add(
    session_id="sesn_011CZkZAtmR3yMPDzynEDxu7",
    file_id="file_011CNha8iCJcU1wXNR6q4V8w",
    type="file",
)
print(beta_managed_agents_file_resource.id)
```

#### Response

```json
{
  "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"
}
```