xref_callers

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It conveys the tool is a static cross-reference lookup ('across the project' and 'what depends on this?') and distinguishes it from runtime call flow via trace_calls. However, it does not explicitly state whether the operation is read-only or describe the output format, leaving minor gaps for an unannotated tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and well-structured: main action in the first sentence, followed by WHEN TO USE and NOT FOR. Every sentence contributes value, with no redundant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has a single well-documented parameter, no output schema, and no annotations. The description covers purpose, usage context, and clear exclusions, making it sufficient for tool selection and invocation. The lack of output format details is a minor omission but not critical for this simple tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema fully documents the only parameter, reference, with a clear description and examples. Since schema coverage is 100%, the description adds no additional parameter meaning beyond the schema, which aligns with the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states the tool's specific verb and resource: 'Find all callers of a module or function across the project' and immediately clarifies the intent with 'what depends on this?'. This distinguishes it clearly from siblings like get_docs and trace_calls, which are explicitly named in the NOT FOR section.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit WHEN TO USE ('Impact analysis before refactoring') and NOT FOR sections, with named alternatives ('use get_docs', 'use trace_calls'), provide direct guidance on when to use this tool versus siblings. This leaves no ambiguity about tool selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.