## Add Session Resource

`BetaManagedAgentsFileResource Beta.Sessions.Resources.Add(ResourceAddParamsparameters, CancellationTokencancellationToken = default)`

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

Add Session Resource

### Parameters

- `ResourceAddParams parameters`

  - `required string sessionID`

    Path param: Path parameter session_id

  - `required string fileID`

    Body param: ID of a previously uploaded file.

  - `required Type type`

    Body param

    - `"file"File`

  - `string? mountPath`

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

  - `IReadOnlyList<AnthropicBeta> betas`

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

    - `"message-batches-2024-09-24"MessageBatches2024_09_24`

    - `"prompt-caching-2024-07-31"PromptCaching2024_07_31`

    - `"computer-use-2024-10-22"ComputerUse2024_10_22`

    - `"computer-use-2025-01-24"ComputerUse2025_01_24`

    - `"pdfs-2024-09-25"Pdfs2024_09_25`

    - `"token-counting-2024-11-01"TokenCounting2024_11_01`

    - `"token-efficient-tools-2025-02-19"TokenEfficientTools2025_02_19`

    - `"output-128k-2025-02-19"Output128k2025_02_19`

    - `"files-api-2025-04-14"FilesApi2025_04_14`

    - `"mcp-client-2025-04-04"McpClient2025_04_04`

    - `"mcp-client-2025-11-20"McpClient2025_11_20`

    - `"dev-full-thinking-2025-05-14"DevFullThinking2025_05_14`

    - `"interleaved-thinking-2025-05-14"InterleavedThinking2025_05_14`

    - `"code-execution-2025-05-22"CodeExecution2025_05_22`

    - `"extended-cache-ttl-2025-04-11"ExtendedCacheTtl2025_04_11`

    - `"context-1m-2025-08-07"Context1m2025_08_07`

    - `"context-management-2025-06-27"ContextManagement2025_06_27`

    - `"model-context-window-exceeded-2025-08-26"ModelContextWindowExceeded2025_08_26`

    - `"skills-2025-10-02"Skills2025_10_02`

    - `"fast-mode-2026-02-01"FastMode2026_02_01`

    - `"output-300k-2026-03-24"Output300k2026_03_24`

    - `"user-profiles-2026-03-24"UserProfiles2026_03_24`

    - `"advisor-tool-2026-03-01"AdvisorTool2026_03_01`

    - `"managed-agents-2026-04-01"ManagedAgents2026_04_01`

    - `"cache-diagnosis-2026-04-07"CacheDiagnosis2026_04_07`

    - `"thinking-token-count-2026-05-13"ThinkingTokenCount2026_05_13`

### Returns

- `class BetaManagedAgentsFileResource:`

  - `required string ID`

  - `required DateTimeOffset CreatedAt`

    A timestamp in RFC 3339 format

  - `required string FileID`

  - `required string MountPath`

  - `required Type Type`

    - `"file"File`

  - `required DateTimeOffset UpdatedAt`

    A timestamp in RFC 3339 format

### Example

```csharp
ResourceAddParams parameters = new()
{
    SessionID = "sesn_011CZkZAtmR3yMPDzynEDxu7",
    FileID = "file_011CNha8iCJcU1wXNR6q4V8w",
    Type = Type.File,
};

var betaManagedAgentsFileResource = await client.Beta.Sessions.Resources.Add(parameters);

Console.WriteLine(betaManagedAgentsFileResource);
```

#### 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"
}
```