AI engineering glossary · Agents tools MCP
What is action space?
Action space: The full set of actions an agent is allowed to take at a given moment, including every available tool and its permitted arguments. A small, well-defined action space makes an agent easier to control and evaluate, while a huge one makes tool selection error-prone.
Action space: an example
A customer support agent's action space is lookup_order, issue_refund, and escalate_to_human, with nothing else permitted.
Related terms
More Agents tools MCP terms
- Agent autonomy level
- Agent benchmark
- Agent card
- Agent evaluation
- Agent handoff
- Agent loop
- Agent memory
- Agent observability
Where you learn it
Action space is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.