Call a tool by name. This is the public API for executing tools. By default, middleware is applied. Args: name: The tool

List all enabled tools from providers. Overrides Provider.list_tools() to add enabled filtering, auth filtering, and middleware execu

Return the value for `key`, or `default` when it is not set.

Create a Tool from a function.

Add a server-level transform. Server-level transforms are applied after all providers are aggregated. They transform tools, resources

Mount another FastMCP server on this server with an optional namespace. Mounting establishes a dynamic connection between servers. When a cli

Add a provider for dynamic tools, resources, and prompts. Providers are queried in registration order. The first provider to return a

List all enabled resources from providers. Overrides Provider.list_resources() to add visibility filtering, auth filtering, and middl

Send a `DEBUG`-level message to the connected MCP Client. Messages sent to Clients are also logged to the `fastmcp.server.context.to_client`

Register a server extension (SEP-2133). An extension contributes a negotiated capability, additive request methods, a `tools/call` in

Enter the server lifespan (Docket backend + worker) for the block.

Store `value` under `key` in this session (read-modify-write). Preserves the creation marker: only the user-state sub-dict is touched.

Get a logger nested under FastMCP namespace. Args: name: the name of the logger, which will be prefixed with 'FastMCP.' Returns:

Disable components matching all specified criteria. Adds a visibility transform that marks matching components as disabled. Component

List all enabled prompts from providers. Overrides Provider.list_prompts() to add visibility filtering, auth filtering, and middlewar

Convert JSON schema to appropriate Python type with validation. Args: schema: A JSON Schema dictionary defining the type structure and va

Decode cursor from an opaque string. Raises: ValueError: If the cursor is invalid or malformed.

Read a resource by URI. This is the public API for reading resources. By default, middleware is applied. Checks concrete resources fi

Create a Starlette app using the specified HTTP transport. Args: path: The path for the HTTP endpoint middleware: A l

List all enabled resource templates from providers. Overrides Provider.list_resource_templates() to add visibility filtering, auth fi

Run an opted-in `tools/call` through the interceptor and return its task.

Generate a test JWT token using symmetric key for testing purposes. Args: subject: Subject claim (usually user ID)

Create a FastMCP proxy server for the given target. This is the recommended way to create a proxy server. For lower-level control, use `FastM

Get a prompt by name, filtering disabled prompts. Overrides Provider.get_prompt() to add visibility filtering after all transforms (i

Look up a cached verification result. Returns: ``(True, AccessToken)`` on a cache hit, ``(False, None)`` on a miss or

Encode cursor state to an opaque string.

Send a `WARNING`-level message to the connected MCP Client. Messages sent to Clients are also logged to the `fastmcp.server.context.to_client

Create a test access token.

Delegate route creation to the server.

Get a tool by name, filtering disabled tools. Overrides Provider.get_tool() to filter disabled tools after all transforms (including

Poll `tasks/get` until the task reaches one of `target_states`.

Reset all state for next test.

Poll until the task reaches `state` (or any terminal state if `None`). Does not answer input prompts: a caller that wants automatic answering

Format the universal name for a backend tool: ``<hash>_<local_name>``.

Mock token verification.

Compress and optimize a JSON schema for MCP compatibility. Args: schema: The schema to compress prune_params: List of parame

POST a jwt-bearer grant to the proxy's /token endpoint via an ASGI app. When ``register`` is True the standard test client is registered first; p

Check if a version matches this spec. Args: version: The version to check, or None for unversioned. match_none: Wheth

Combines parameter and request body schemas into a single schema. Handles parameter name collisions by adding location suffixes. Also ret

Set the access token in the auth context var.

Mint a fake ID-JAG JWT with full control over header and claims. `client_id` and `resource` default to values matching the standard test clie

Render a prompt by name. This is the public API for rendering prompts. By default, middleware is applied. Use get_prompt() to retriev

Convert an OpenAPI schema to JSON Schema format. This is a clean, systematic approach that: 1. Removes OpenAPI-specific fields 2. Co

Create a copy of the component.

Send a `ERROR`-level message to the connected MCP Client. Messages sent to Clients are also logged to the `fastmcp.server.context.to_client`

Get the FastMCP access token from the current context. This function first tries to get the token from the current HTTP request's scope, whic

Require all of the given OAuth scopes.

Send a cancellation notification for an in-progress request.

Enable components matching all specified criteria. Adds a visibility transform that marks matching components as enabled. Later trans

Create a mock tool for testing.

Render the prompt with arguments. Subclasses must implement this method. Return one of: - str: Wrapped as single user Message

Run auth checks with AND logic, stopping at the first failure.

Start a FastMCP server on a real port as an asyncio task. This runs a real uvicorn server in the current process, bound to a real TCP port,

Add a tool to the server. The tool function can optionally request a Context object by adding a parameter with the Context type annot

Override to preserve _backend_name when name changes.

Parse scopes from environment variables or settings values. Accepts either a JSON array string, a comma- or space-separated string, a list of

Extract information from a FastMCP instance into a dataclass. This function automatically detects whether the instance is FastMCP v1.x or v2.x

Securely check if a URI matches an allowed pattern with wildcard support. This function parses both the URI and pattern as URLs, comparing each

Add two numbers.

Create a resource from the template with the given parameters. The base implementation does not support background tasks. Use Functio

TypeAdapters are heavy objects, and in an application context we'd typically create them once in a global scope and reuse them as often as po

Send a `INFO`-level message to the connected MCP Client. Messages sent to Clients are also logged to the `fastmcp.server.context.to_client` l

Return an instance of the StreamableHTTP server app. Args: server: The FastMCP server instance streamable_http_path: Path for Str

Find an available port by letting the OS assign one.

Import a Python file as a module. If the file is part of a package (directory has __init__.py), imports it as a proper package member (relati

Check if component is enabled. Returns True if: - No visibility mark exists (default is enabled) - Visibility mark is True Returns F

Temporarily override FastMCP setting values. Args: **kwargs: The settings to override, including nested settings. Example:

Send a log message to the client. Messages sent to Clients are also logged to the `fastmcp.server.context.to_client` logger with a level of `

Submit a task and wait for it to reach a terminal state.

Convert the FastMCP tool to an MCP tool.

Extract a string result from a ToolResult.

Register a client locally When a client registers, we create a ProxyDCRClient that is more forgiving about validating redirect URIs,

Search for available tools by query. Returns matching tools ranked by relevance.