Built-In Echo Tool¶

The included built-in tool is echo. It returns the provided text unchanged, which makes it useful for checking tool wiring without depending on external data.

Run a ReAct agent with the tool:

yaaf agent --name react --tool echo "Use the echo tool to repeat hello."

Call the same tool from ask:

yaaf ask --tool echo "Echo hello."

Expected trace shape:

thought: I need to echo the requested text.
tool: echo {"text":"hello"}
observation: hello
yaaf: ...final answer using the echoed result...

Unknown tools fail before contacting Ollama:

yaaf agent --name react --tool unknown "test prompt"

Expected error shape:

yaaf failed: unknown tool: unknown (available tools: echo)