PrefectHQ/fastmcp
Documented errors, page 5 of 5. Back to PrefectHQ/fastmcp
| Code / Message | Type | Severity | Tags |
|---|---|---|---|
| Elicitation schema field | exception | error | elicitation, json-schema, nested-objects, fastmcp |
| Elicitation schema field | exception | error | elicitation, json-schema, nested-objects, fastmcp |
| Invalid URL for configuration metadata | validation | error | oidc, configuration, url-validation |
| Not a file | validation | error | not-a-file, skill-provider, filesystem, validation |
| Unsupported image MIME type for OpenAI | validation | error | openai, sampling, image, mime-type |
| First argument to @ must be a function, string, or None, got | exception | error | python, typeerror, decorator-usage |
| StreamingASGITransport requires an async request stream; got | exception | error | python, httpx, asgi, streaming |
| Both 'httpx_client_factory' and 'verify' were provided. The… | console | warning | python, ssl, httpx, transport |
| mcp_prompt() got unexpected keyword argument(s) | exception | error | python, decorator, type-error, fastmcp |
| interval_ms must be positive | validation | error | configuration, validation, middleware |
| The API key is empty | validation | error | pydantic, validation, api-key |
| CIMD document must specify private_key_jwt auth method | exception | error | oauth, cimd, auth-method-mismatch, private-key-jwt |
| Failed to execute module | exception | error | python, import, module-loading, plugin-discovery |
| First argument to @tool must be a function, string, or… | exception | error | python, fastmcp, tools, type-error |
| Cannot specify both 'hide=True' and 'required=True'. Hidden… | validation | error | python, tool-transform, validation |
| Cannot specify 'required=True' with 'default' or… | validation | error | python, tool-transform, validation |
| Invalid JWT format (expected 3 parts) | exception | error | python, jwt, auth, base64 |
| Cannot specify both 'default' and 'default_factory' in… | validation | error | python, tool-transform, validation |
| To decorate a classmethod, use @classmethod above @tool… | validation | error | python, decorators, classmethod, tool-definition |
| messages[ ] must be Message or str, got . Use Message( ) to… | exception | error | prompts, type-error, validation, python |
| Passing an httpx.AsyncClient to OpenAPIProvider is… | console | warning | python, deprecation, openapi, httpx |
| Unsupported tool_choice mode | validation | error | anthropic, sampling, tool-choice, valueerror |
| File not found. Available | exception | error | python, valueerror, file-not-found, session-scope |
| Amount must be at least 1 | validation | error | progress, validation, fastmcp |
| Cannot determine tool name for | exception | error | python, valueerror, tool-registration |
| Failed to convert JWK to PEM | exception | error | oauth, jwks, key-format, cryptography |
| uri is required when metadata is not provided | validation | error | python, resources, missing-argument |
| Assertion JOSE header must be a JSON object | exception | error | jwt, malformed, json, schema |
| ClientGroup requires at least one client | validation | error | python, validation, configuration, client-group |
| OIDC discovery document for issuer | exception | error | oidc, discovery, jwks, configuration |
| Cannot load spec for | exception | error | python, import, spec, file-loading |
| AudioContent is only supported in user messages for OpenAI | validation | error | openai, sampling, audio, validation |
| Unsupported content type for Anthropic | validation | error | anthropic, sampling, content-type, conversion |
| ImageContent is only supported in user messages for… | validation | error | anthropic, sampling, image, message-role |
| Expected Prompt or @prompt-decorated function, got | exception | error | python, type-error, prompts, api-misuse |
| Missing required client id | validation | error | oidc, configuration, missing-parameter |
| The `openai` package is not installed. Please install… | exception | error | dependency, openai, import-error |
| SSE transport does not support stateless mode | validation | error | transport, sse, stateless, configuration |
| Invalid root | validation | error | mcp, roots, validation, client |
| Assertion lifetime too long | exception | error | oauth, jwt, private-key-jwt, validation |
| No response for completion | exception | error | openai, sampling, empty-response, api |
| Prompt version not found | exception | error | keyerror, prompt, versioning, removal |
| Cannot specify both a name as first argument and as keyword… | exception | error | python, fastmcp, tools, api-misuse |
| Invalid roots handler | validation | error | mcp, roots, validation, client |
| Horizon authentication is required | exception | error | cli, authentication, missing-credentials |
| Resource version not found | exception | error | keyerror, resource, versioning, removal |
| Either client_secret or jwt_signing_key must be provided… | validation | error | oidc, configuration, client-secret |
| Prompt not found | exception | error | keyerror, prompt, removal |
| Template version not found | exception | error | keyerror, resource-template, versioning, removal |
| Discovery tools must have unique names. | exception | error | code-mode, naming-collision, value-error, fastmcp |
| Unsupported audio MIME type for OpenAI | validation | error | openai, sampling, audio, mime-type |
| Missing required config URL | validation | error | oidc, configuration, missing-parameter |
| Assertion payload is not a JSON object | exception | error | jwt, malformed, json, schema |
| messages must be str or list[Message], got | exception | error | prompts, type-error, validation, python |
| Unknown transport | validation | error | transport, configuration, valueerror |
| Unsupported image MIME type for Anthropic | validation | error | anthropic, sampling, image, mime-type |
| Cannot specify both a name as first argument and as keyword… | exception | error | python, argument-conflict, decorators, prompts |
| Cannot mount a server onto itself | validation | error | python, server, mount, recursion |
| visibility cannot be set on resources — it only applies to… | validation | error | python, resources, config, visibility |
| AudioContent is not supported by the Anthropic API | validation | error | anthropic, sampling, audio, unsupported |
| Missing required base URL | validation | error | oidc, configuration, missing-parameter |