---
title: components
sidebarTitle: components
---
# `fastmcp.utilities.components`
## Functions
### `get_fastmcp_metadata`
```python
get_fastmcp_metadata(meta: dict[str, Any] | None) -> FastMCPMeta
```
Extract FastMCP metadata from a component's meta dict.
Handles both the current `fastmcp` namespace and the legacy `_fastmcp`
namespace for compatibility with older FastMCP servers.
## Classes
### `FastMCPMeta`
### `FastMCPComponent`
Base class for FastMCP tools, prompts, resources, and resource templates.
**Methods:**
#### `make_key`
```python
make_key(cls, identifier: str) -> str
```
Construct the lookup key for this component type.
**Args:**
- `identifier`: The raw identifier (name for tools/prompts, uri for resources)
**Returns:**
- A prefixed key like "tool:name" or "resource:uri"
#### `key`
```python
key(self) -> str
```
The globally unique lookup key for this component.
Format: "{key_prefix}:{identifier}@{version}" or "{key_prefix}:{identifier}@"
e.g. "tool:my_tool@v2", "tool:my_tool@", "resource:file://x.txt@"
The @ suffix is ALWAYS present to enable unambiguous parsing of keys
(URIs may contain @ characters, so we always include the delimiter).
Subclasses should override this to use their specific identifier.
Base implementation uses name.
Prefer `.key` over ad-hoc `name or uri or uri_template` logic for any
cross-component identity work (dedupe, grouping, collision detection,
lookup tables). It encodes type, identifier, and version, so variants
of the same component don't falsely collide with each other, and
cross-type identifiers (e.g. a tool and a resource both named "foo")
can't clash.
#### `get_meta`
```python
get_meta(self) -> dict[str, Any]
```
Get the meta information about the component.
Returns a dict that always includes a `fastmcp` key containing:
- `tags`: sorted list of component tags
- `version`: component version (only if set)
Internal keys (prefixed with `_`) are stripped from the fastmcp namespace.
#### `enable`
```python
enable(self) -> None
```
Removed in 3.0. Use server.enable(keys=[...]) instead.
#### `disable`
```python
disable(self) -> None
```
Removed in 3.0. Use server.disable(keys=[...]) instead.
#### `copy`
```python
copy(self) -> Self
```
Create a copy of the component.
#### `get_span_attributes`
```python
get_span_attributes(self) -> dict[str, Any]
```
Return span attributes for telemetry.
Subclasses should call super() and merge their specific attributes.