> ## 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. # Validate a blueprint > Lint blueprint YAML without saving it. Returns 200 with `ok: false` + structured errors for an invalid blueprint; the authoritative rejection still happens at create/update/build. ## OpenAPI ````yaml /reference/openapi.json post /projects/{projectId}/images/validate 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). paths: /projects/{projectId}/images/validate: post: tags: - Sandbox images summary: Validate a blueprint description: >- Lint blueprint YAML without saving it. Returns 200 with `ok: false` + structured errors for an invalid blueprint; the authoritative rejection still happens at create/update/build. operationId: validateSandboxImageBlueprint parameters: - $ref: '#/components/parameters/projectId' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SandboxImageBlueprintValidateRequest' example: blueprint: | base: debian:bookworm-slim@sha256: initialize: - name: Install tooling run: apt-get update && apt-get install -y git knowledge: - name: Test notes contents: Run `make test` before pushing. responses: '200': description: Lint result content: application/json: schema: $ref: '#/components/schemas/SandboxImageBlueprintValidateResult' '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 schemas: SandboxImageBlueprintValidateRequest: type: object additionalProperties: false required: - blueprint properties: blueprint: type: string description: Blueprint YAML to lint. SandboxImageBlueprintValidateResult: type: object description: >- Lint result. `ok: true` carries the resolved base digest; `ok: false` carries structured errors. Always returned with HTTP 200 — an invalid blueprint is a successful lint. required: - ok properties: ok: type: boolean baseImageDigest: type: string description: Resolved sha256 digest of `base` (present when ok). errors: type: array items: type: object required: - path - message properties: path: type: string description: >- Location of the violation, e.g. `initialize[0].run` (empty for document-level errors). message: type: string oneOf: - required: - baseImageDigest properties: ok: const: true - required: - errors properties: ok: const: false 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. ````