> ## Documentation Index > Fetch the complete documentation index at: https://docs.mcpjam.com/llms.txt > Use this file to discover all available pages before exploring further. # Replace a host's server attachments > Sets the host's required and optional server ids without round-tripping its whole config, and responds with the updated host detail. Preserves every other identity field (computer, harness, built-in tools) and trims per-server connection overrides to the kept set. Requires project admin. ## OpenAPI ````yaml /reference/openapi.json post /projects/{projectId}/hosts/{hostId}/servers openapi: 3.1.0 info: title: MCPJam API version: 1.0.0-preview description: >- Programmatic access to MCP servers saved in your MCPJam projects — live diagnostics (validate, inspect, export) and operations: call tools, render prompts, run eval suites asynchronously and poll their results, and import OAuth tokens. **The API is in preview**: the surface may change while we finish the design. Error `code` values are stable; error `message` strings are not. Write clients that ignore unknown response fields. contact: name: MCPJam url: https://github.com/MCPJam/inspector/issues servers: - url: https://app.mcpjam.com/api/v1 description: Hosted MCPJam security: - bearerAuth: [] tags: - name: Hosts description: >- Project hosts: named model + capability profiles you run chats and eval suites against. - name: Environments description: >- Project environments: named, live-editable execution bundles (one host, an optional standalone server group, optionally pinned skills and plugin versions) that eval suites and journeys run against. Distinct from Sandbox images, which are Computer base images. Reads require project membership; every write requires project admin. - name: Sandbox images description: >- Custom Computer images: a digest-pinned Dockerfile built into an immutable image your project's computers boot from. - name: Server diagnostics description: Connect-level health checks against a saved MCP server. - name: Primitives description: 'The server''s MCP primitives: tools, prompts, and resources.' - name: Export description: Full-server snapshots for diffing and CI. - name: Execution description: 'Run the server''s primitives: call tools, render prompts.' - name: Eval runs description: >- Asynchronous eval suite runs: create with 202, poll status, iterations, and traces. - name: OAuth description: 'Bring-your-own OAuth: import externally obtained tokens for a server.' - name: Chatboxes description: >- Read-only access to the chatboxes published from a project: listing, settings, attached servers, and share links. - name: Catalog description: >- Discover the resources the other routes operate on: your account, projects, servers, eval suites, and chat sessions. - name: Tunnels description: >- Relay tunnels that expose local MCP servers through a public URL, registered as first-class project servers (the `mcpjam tunnel` CLI flow). - name: Agent description: >- Headless agent turns over the public API: send a message history, the server runs one assistant turn with project-scoped workspace tools (eval reads + suite creation) on a pinned hosted model, and returns the reply plus created-resource references. paths: /projects/{projectId}/hosts/{hostId}/servers: post: tags: - Hosts summary: Replace a host's server attachments description: >- Sets the host's required and optional server ids without round-tripping its whole config, and responds with the updated host detail. Preserves every other identity field (computer, harness, built-in tools) and trims per-server connection overrides to the kept set. Requires project admin. operationId: setHostServers parameters: - $ref: '#/components/parameters/projectId' - $ref: '#/components/parameters/hostId' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/HostServersRequest' example: serverIds: - srv_1 optionalServerIds: [] responses: '200': description: The updated host. content: application/json: schema: $ref: '#/components/schemas/HostDetail' '400': $ref: '#/components/responses/ValidationError' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/InternalError' '502': $ref: '#/components/responses/ServerUnreachable' components: parameters: projectId: name: projectId in: path required: true description: ID of the hosted project that contains the server. schema: type: string hostId: name: hostId in: path required: true description: Host ID, as returned by the project's host list. schema: type: string schemas: HostServersRequest: type: object description: >- Replaces the host's server attachments wholesale. Every id must name a live server in the same project. required: - serverIds additionalProperties: false properties: serverIds: type: array items: type: string optionalServerIds: type: array items: type: string description: Attached but not required to connect. HostDetail: type: object description: >- A host plus its resolved host config (model, capabilities, host context, MCP profile). required: - id - name - config properties: id: type: string name: type: string config: type: object additionalProperties: true description: >- Host config v2 DTO. Opaque object; shape mirrors the inspector's host editor. Error: type: object required: - code - message properties: code: type: string description: >- Stable, machine-readable error code. New codes may be added over time; treat unknown codes as non-retryable failures unless the HTTP status says otherwise. enum: - UNAUTHORIZED - FORBIDDEN - NOT_FOUND - CONFLICT - VALIDATION_ERROR - RATE_LIMITED - FEATURE_NOT_SUPPORTED - SERVER_UNREACHABLE - TIMEOUT - OAUTH_REQUIRED - INTERNAL_ERROR message: type: string description: >- Human-readable description. May change between releases — don't match on it. details: type: object description: Optional, unstructured context bag. additionalProperties: true responses: ValidationError: description: Malformed body or parameters. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: VALIDATION_ERROR message: Invalid JSON body Unauthorized: description: >- Missing, invalid, revoked, or orphaned key (`UNAUTHORIZED`) — or the **target MCP server** needs an OAuth grant (`OAUTH_REQUIRED`), which is a property of the server, not your key. content: application/json: schema: $ref: '#/components/schemas/Error' examples: badKey: summary: Invalid or revoked key value: code: UNAUTHORIZED message: Invalid API key oauthRequired: summary: Target server needs an OAuth grant value: code: OAUTH_REQUIRED message: Server requires OAuth authorization Forbidden: description: Key is valid but not allowed to do this. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: FORBIDDEN message: You do not have access to this project NotFound: description: Unknown project, server, or resource. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: NOT_FOUND message: Server not found RateLimited: description: >- Per-key rate limit exceeded (60 requests/minute sustained, bursts up to 10). Honor `Retry-After` and back off with jitter. headers: Retry-After: description: Seconds to wait before retrying. schema: type: integer content: application/json: schema: $ref: '#/components/schemas/Error' example: code: RATE_LIMITED message: API key rate limit exceeded. Slow down and retry. InternalError: description: Something failed on MCPJam's side. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: INTERNAL_ERROR message: Unexpected internal error ServerUnreachable: description: Could not connect to the target MCP server. content: application/json: schema: $ref: '#/components/schemas/Error' example: code: SERVER_UNREACHABLE message: Failed to connect to server securitySchemes: bearerAuth: type: http scheme: bearer description: >- MCPJam API key (`sk_…`). Create one at [Settings → API keys](https://app.mcpjam.com/settings/api-keys). Guest sessions cannot use the API, and API keys cannot manage other API keys. ````