> ## Documentation Index > Fetch the complete documentation index at: https://docs.langchain.com/llms.txt > Use this file to discover all available pages before exploring further. # Register an MCP server > Register an MCP server in the caller's workspace. Static-header servers can include credential headers. OAuth servers should set `auth_type=oauth` and `oauth_mode=per_user_dynamic_client`, then register an OAuth provider and start an auth session before use. ## OpenAPI ````yaml /langsmith/managed-deep-agents-openapi.json post /mcp-servers openapi: 3.1.0 info: title: Managed Deep Agents API version: 0.1.0 description: Create, configure, and run Managed Deep Agents. servers: - url: https://api.smith.langchain.com/v1/deepagents security: - apiKeyAuth: [] tags: - name: Agents description: Create and manage Managed Deep Agent resources. - name: Threads description: Create and inspect durable thread state. - name: Runs description: Start runs on Managed Deep Agent threads. - name: MCP servers description: Register MCP servers and store credentials referenced by agent tools. - name: MCP tools description: List tools exposed by registered MCP servers. - name: Auth sessions description: Start and poll OAuth authorization sessions for OAuth MCP servers. paths: /mcp-servers: post: tags: - MCP servers summary: Register an MCP server description: >- Register an MCP server in the caller's workspace. Static-header servers can include credential headers. OAuth servers should set `auth_type=oauth` and `oauth_mode=per_user_dynamic_client`, then register an OAuth provider and start an auth session before use. operationId: createMcpServer requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreateMcpServerRequest' examples: basic: summary: Register Tavily's hosted MCP server with a bearer credential value: name: tavily url: https://mcp.tavily.com/mcp/ headers: - key: Authorization value: Bearer tvly-... oauth: summary: Register an OAuth MCP server value: name: github-tools url: https://example.com/mcp auth_type: oauth oauth_mode: per_user_dynamic_client responses: '201': description: MCP server registered. content: application/json: schema: $ref: '#/components/schemas/McpServer' examples: basic: summary: Newly registered Tavily MCP server value: id: 5b6f6a2b-2c95-4f0f-9c2b-7c3a3e4f8d11 tenant_id: 33499cf9-4c02-49af-909d-b8f42e051eab name: tavily url: https://mcp.tavily.com/mcp/ headers: - key: Authorization value: Bearer tvly-... auth_type: '' oauth_mode: '' created_at: '2026-05-20T20:50:32.708302+00:00' updated_at: '2026-05-20T20:50:32.708302+00:00' mcp_vendor_id: null vendor_id: null external_system_id: null '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '409': $ref: '#/components/responses/Conflict' '422': $ref: '#/components/responses/UnprocessableEntity' '500': $ref: '#/components/responses/InternalServerError' '502': $ref: '#/components/responses/BadGateway' '503': $ref: '#/components/responses/ServiceUnavailable' components: schemas: CreateMcpServerRequest: type: object required: - name - url properties: name: type: string description: Human-readable name for the MCP server. url: type: string format: uri description: MCP server URL. Must be a valid HTTPS endpoint. headers: type: array items: $ref: '#/components/schemas/McpServerHeader' description: >- Credential headers attached to every invocation of this MCP server. Omitted from response bodies when the caller lacks invoke permission on the server. auth_type: $ref: '#/components/schemas/AuthType' oauth_provider_id: type: - string - 'null' format: uuid description: Optional OAuth provider ID for legacy shared OAuth providers. oauth_mode: $ref: '#/components/schemas/OAuthMode' vendor_id: type: string description: Optional vendor identifier for catalog grouping. external_system_id: type: string description: Optional opaque external system identifier. McpServer: type: object properties: id: type: string format: uuid tenant_id: type: string format: uuid name: type: string url: type: string format: uri headers: type: array items: $ref: '#/components/schemas/McpServerHeader' description: >- Credential headers attached to every invocation of this MCP server. Omitted from response bodies when the caller lacks invoke permission on the server. auth_type: $ref: '#/components/schemas/AuthType' oauth_provider_id: type: - string - 'null' format: uuid description: >- OAuth provider ID for legacy shared OAuth providers, when configured. oauth_mode: $ref: '#/components/schemas/OAuthMode' created_at: type: string format: date-time updated_at: type: string format: date-time mcp_vendor_id: type: - string - 'null' vendor_id: type: - string - 'null' external_system_id: type: - string - 'null' can_invoke: type: boolean description: >- Whether the caller has invoke permission on this server. Omitted when ambient permissions already imply invoke. McpServerHeader: type: object required: - key - value description: A single header attached to MCP server invocations. properties: key: type: string description: Header name (for example, `Authorization`). value: type: string description: Header value. May contain secrets such as bearer tokens. AuthType: type: string enum: - headers - oauth description: Authentication scheme used by the MCP server. OAuthMode: type: string enum: - legacy_shared_provider - per_user_dynamic_client description: OAuth mode used by an OAuth MCP server. ErrorResponse: type: object properties: type: type: string code: type: string detail: type: string status: type: integer responses: BadRequest: description: Bad request. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: missingRequiredField: summary: Required field missing value: type: https://docs.langchain.com/errors/missing_required_field code: missing_required_field detail: 'Set ''name'' to a non-empty string: ''name'' is required' status: 400 invalidRequestBody: summary: Malformed JSON body value: type: https://docs.langchain.com/errors/invalid_request_body code: invalid_request_body detail: >- Provide a valid JSON request body matching the documented schema status: 400 Unauthorized: description: >- Authentication required. The auth layer returns a simple `{"error": "Unauthorized"}` body that does not match the structured `ErrorResponse` shape used by other 4xx responses. content: application/json: schema: type: object properties: error: type: string examples: missingApiKey: summary: No `X-Api-Key` header supplied value: error: Unauthorized Forbidden: description: >- The authenticated identity does not have access to the resource or feature. The auth layer returns a simple `{"error": "Forbidden"}` body that does not match the structured `ErrorResponse` shape used by other 4xx responses. content: application/json: schema: type: object properties: error: type: string examples: invalidApiKey: summary: API key is invalid or lacks workspace access value: error: Forbidden Conflict: description: Request conflicts with current resource state. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' UnprocessableEntity: description: Request is syntactically valid but failed validation. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' InternalServerError: description: Internal server error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' BadGateway: description: Upstream agent runtime error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' examples: upstreamAuthFailed: summary: >- Upstream runtime rejected the request (e.g. orphaned thread after agent deletion) value: type: https://docs.langchain.com/errors/upstream_auth_failed code: upstream_auth_failed detail: >- Verify that the calling identity is authorized for this organization: upstream agent runtime rejected the request status: 502 ServiceUnavailable: description: Dependent service unavailable. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: apiKeyAuth: type: apiKey in: header name: X-Api-Key x-default: LANGSMITH_API_KEY ````