fastmcp/examples/sampling/README.md
Jeremiah Lowin 577f4d1bdf
Consolidate sampling examples and fix tool_choice bug (#2618)
* Fix tool_choice to always require tools when result_type is set

* Consolidate sampling examples with rich output

* Replace eval() with explicit add/multiply tools
2025-12-14 20:47:00 -05:00

62 lines
1.3 KiB
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# Sampling Examples
These examples demonstrate FastMCP's sampling API, which allows server tools to request LLM completions from the client.
## Prerequisites
```bash
pip install fastmcp[anthropic]
export ANTHROPIC_API_KEY=your-key
```
Or run directly with `uv`:
```bash
uv run examples/sampling/text.py
```
## Examples
### Simple Text Sampling (`text.py`)
Basic sampling flow where a server tool requests an LLM completion:
```bash
uv run examples/sampling/text.py
```
### Structured Output (`structured_output.py`)
Uses `result_type` to get validated Pydantic models from the LLM:
```bash
uv run examples/sampling/structured_output.py
```
### Tool Use (`tool_use.py`)
Gives the LLM tools to use during sampling (calculator, time, dice):
```bash
uv run examples/sampling/tool_use.py
```
### Server Fallback (`server_fallback.py`)
Configures a fallback sampling handler on the server, enabling sampling even when clients don't support it:
```bash
uv run examples/sampling/server_fallback.py
```
## Using OpenAI Instead
To use OpenAI instead of Anthropic, change the handler:
```python
from fastmcp.client.sampling.handlers.openai import OpenAISamplingHandler
handler = OpenAISamplingHandler(default_model="gpt-4o-mini")
```
And install with `pip install fastmcp[openai]`.