Tools turn an operation into actual execution. For example, reading data, calculating a time total, or generating a PPT file—each has inputs and observable results.
Distinguishing Three Phases
"Preparing to read" is planning; a tool call is an execution attempt; returned data is the result of this read. When an error is returned, it should be handled—no call having been made counts as success.
| Result | What Conclusion Can Be Drawn |
|---|---|
| Returns course materials | The specified query obtained this content |
| Returns file path and success status | The file may have been generated; still need to verify it opens |
| Returns an error | This operation did not complete as expected |
Where Tools Come From
Applications can have built-in tools, or connect through interfaces or MCP services. Tool names may appear identical, but actual parameters, scope, and permissions can differ.
How to Use Results Next
Agents can use returned results as a basis for subsequent judgments. Regular workflows can also directly invoke tools without requiring the model to decide every step.
See MCP Verified Queries to see a real tool list, calls, and data returns.
Related Concepts in This Section
- Tool: A specific capability that a system can invoke, such as searching, reading files, calculating, or generating files.
For general definitions and technical sources, see the related concepts page, verified on: 2026-09-09. The examples in this section are written for instructional purposes; optional checks serve comprehension and do not restrict further reading.