fastmcp/docs/python-sdk/fastmcp-resources-resource.mdx

---
title: resource
sidebarTitle: resource
---

# `fastmcp.resources.resource`


Base classes and interfaces for FastMCP resources.

## Classes

### `ResourceContent` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L35" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


Wrapper for resource content with optional MIME type and metadata.

Accepts any value for content - strings and bytes pass through directly,
other types (dict, list, BaseModel, etc.) are automatically JSON-serialized.


**Methods:**

#### `to_mcp_resource_contents` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L90" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
to_mcp_resource_contents(self, uri: AnyUrl | str) -> mcp.types.TextResourceContents | mcp.types.BlobResourceContents
```

Convert to MCP resource contents type.

**Args:**
- `uri`: The URI of the resource (required by MCP types)

**Returns:**
- TextResourceContents for str content, BlobResourceContents for bytes


### `ResourceResult` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L117" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


Canonical result type for resource reads.

Provides explicit control over resource responses: multiple content items,
per-item MIME types, and metadata at both the item and result level.


**Methods:**

#### `to_mcp_result` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L192" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
to_mcp_result(self, uri: AnyUrl | str) -> mcp.types.ReadResourceResult
```

Convert to MCP ReadResourceResult.

**Args:**
- `uri`: The URI of the resource (required by MCP types)

**Returns:**
- MCP ReadResourceResult with converted contents


### `Resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L208" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


Base class for all resources.


**Methods:**

#### `from_function` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L229" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
from_function(fn: Callable[..., Any], uri: str | AnyUrl, name: str | None = None, title: str | None = None, description: str | None = None, icons: list[Icon] | None = None, mime_type: str | None = None, tags: set[str] | None = None, annotations: Annotations | None = None, meta: dict[str, Any] | None = None, task: bool | TaskConfig | None = None) -> FunctionResource
```

#### `set_default_mime_type` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L258" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
set_default_mime_type(cls, mime_type: str | None) -> str
```

Set default MIME type if not provided.


#### `set_default_name` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L265" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
set_default_name(self) -> Self
```

Set default name from URI if not provided.


#### `read` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L275" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
read(self) -> str | bytes | ResourceResult
```

Read the resource content.

Subclasses implement this to return resource data. Supported return types:
    - str: Text content
    - bytes: Binary content
    - ResourceResult: Full control over contents and result-level meta


#### `convert_result` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L287" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
convert_result(self, raw_value: Any) -> ResourceResult
```

Convert a raw result to ResourceResult.

This is used in two contexts:
1. In _read() to convert user function return values to ResourceResult
2. In tasks_result_handler() to convert Docket task results to ResourceResult

Handles ResourceResult passthrough and converts raw values using
ResourceResult's normalization.


#### `to_mcp_resource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L343" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
to_mcp_resource(self, **overrides: Any) -> SDKResource
```

Convert the resource to an SDKResource.


#### `key` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L368" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
key(self) -> str
```

The globally unique lookup key for this resource.


#### `register_with_docket` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L372" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
register_with_docket(self, docket: Docket) -> None
```

Register this resource with docket for background execution.


#### `add_to_docket` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L378" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
add_to_docket(self, docket: Docket, **kwargs: Any) -> Execution
```

Schedule this resource for background execution via docket.

**Args:**
- `docket`: The Docket instance
- `fn_key`: Function lookup key in Docket registry (defaults to self.key)
- `task_key`: Redis storage key for the result
- `**kwargs`: Additional kwargs passed to docket.add()


### `FunctionResource` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L400" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


A resource that defers data loading by wrapping a function.

The function is only called when the resource is read, allowing for lazy loading
of potentially expensive data. This is particularly useful when listing resources,
as the function won't be called until the resource is actually accessed.

The function can return:
- str for text content (default)
- bytes for binary content
- other types will be converted to JSON


**Methods:**

#### `from_function` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L416" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
from_function(cls, fn: Callable[..., Any], uri: str | AnyUrl, name: str | None = None, title: str | None = None, description: str | None = None, icons: list[Icon] | None = None, mime_type: str | None = None, tags: set[str] | None = None, annotations: Annotations | None = None, meta: dict[str, Any] | None = None, task: bool | TaskConfig | None = None) -> FunctionResource
```

Create a FunctionResource from a function.


#### `read` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L462" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
read(self) -> str | bytes | ResourceResult
```

Read the resource by calling the wrapped function.


#### `register_with_docket` <sup><a href="https://github.com/jlowin/fastmcp/blob/main/src/fastmcp/resources/resource.py#L478" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
register_with_docket(self, docket: Docket) -> None
```

Register this resource with docket for background execution.

FunctionResource registers the underlying function, which has the user's
Depends parameters for docket to resolve.