> ## Documentation Index
> Fetch the complete documentation index at: https://gofastmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.
# keys
# `fastmcp.server.tasks.keys`
Docket and Redis key encoding for background tasks.
The compound Docket task key embeds the auth boundary so that the parser can
reject cross-scope access without consulting Redis. Authenticated and
anonymous tasks live in disjoint keyspaces:
auth:{enc_scope}:{client_task_id}:{task_type}:{enc_identifier}
anon:{client_task_id}:{task_type}:{enc_identifier}
The same `auth/anon` partition is used for the per-task Redis prefix
(`fastmcp:task:auth:{enc_scope}` vs `fastmcp:task:anon`) — see
`task_redis_prefix`.
`task_scope` is the raw scope identifier (typically derived from
`client_id` or `client_id|sub`); encoding happens once, at the boundary,
in this module.
## Functions
### `build_task_key`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
build_task_key(task_scope: str | None, client_task_id: str, task_type: str, component_identifier: str) -> str
```
Build Docket task key with embedded metadata.
When `task_scope` is `None` the task is anonymous and lives in the
`anon` keyspace. Otherwise it lives under `auth:{enc_scope}`.
**Args:**
* `task_scope`: Raw authorization scope, or `None` for anonymous tasks
* `client_task_id`: Client-provided task ID
* `task_type`: Type of task ("tool", "prompt", "resource")
* `component_identifier`: Tool name, prompt name, or resource URI
**Returns:**
* Encoded task key for Docket
**Examples:**
> > > build\_task\_key("client-a", "task456", "tool", "my\_tool")
> > > 'auth:client-a:task456:tool:my\_tool'
> > > build\_task\_key(None, "task456", "tool", "my\_tool")
> > > 'anon:task456:tool:my\_tool'
> > > build\_task\_key("client-a", "task456", "resource", "file://data.txt")
> > > 'auth:client-a:task456:resource:file%3A%2F%2Fdata.txt'
### `parse_task_key`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
parse_task_key(task_key: str) -> TaskKeyParts
```
Parse Docket task key to extract metadata.
**Args:**
* `task_key`: Encoded task key from Docket
**Returns:**
* Dict with keys: `task_scope` (`str | None`), `client_task_id`,
* `task_type`, `component_identifier`.
**Raises:**
* `ValueError`: If the key has an unrecognized tag or wrong segment count.
**Examples:**
> > > parse\_task\_key("auth:client-a:task456:tool:my\_tool")
> > > `{'task_scope': 'client-a', 'client_task_id': 'task456', 'task_type': 'tool', 'component_identifier': 'my_tool'}`
> > > parse\_task\_key("anon:task456:tool:my\_tool")
> > > `{'task_scope': None, 'client_task_id': 'task456', 'task_type': 'tool', 'component_identifier': 'my_tool'}`
### `get_client_task_id_from_key`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
get_client_task_id_from_key(task_key: str) -> str
```
Extract just the client task ID from a task key.
**Args:**
* `task_key`: Full encoded task key
**Returns:**
* Client-provided task ID
**Examples:**
> > > get\_client\_task\_id\_from\_key("auth:client-a:task456:tool:my\_tool")
> > > 'task456'
> > > get\_client\_task\_id\_from\_key("anon:task456:tool:my\_tool")
> > > 'task456'
### `task_redis_prefix`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
task_redis_prefix(task_scope: str | None) -> str
```
Return the Redis key prefix that owns a given scope.
Authenticated tasks live under `fastmcp:task:auth:{enc_scope}`;
anonymous tasks live under `fastmcp:task:anon`. Callers append
`f":{task_id}:..."` to compose the final key.
## Classes
### `TaskKeyParts`
Decoded segments of a Docket task key.
`task_scope` is `None` for anonymous tasks, the raw scope string
otherwise.