Tool result

Also called: tool output, tool response, function result, tool results, observation

What comes back to the model after it uses a tool: a file's contents, the output of a command, a search result or an error. Tool results are the agent's only view of the world, and long ones fill the context window quickly.

For example: The agent runs the tests, the tool result shows three failures and their causes, and the agent's next step is to fix those three.