lookup_symbol

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

With no annotations, the description carries the full burden. It discloses the return format ('Dictionary containing location, definition, and evidence sources') but does not mention error behavior, case sensitivity, repository requirements, or read-only guarantees.

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 five lines with clear 'Args' and 'Returns' sections. It front-loads the primary purpose and every sentence contributes useful information without redundancy.

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 is simple with three parameters, one required, and the description covers purpose, parameters, and return shape. It lacks explicit edge-case behavior (e.g., symbol not found) but is largely complete for a lookup operation. The output schema further reduces the need to detail return values.

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 Args section explains all three parameters, adding meaning absent from the schema's bare property names. It clarifies that kind and repo are optional filters, and repo filters by repository, which meaningfully goes beyond the schema structure.

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 'Look up a specific symbol (function, struct, macro) in kernel source,' which clearly identifies the action, resource, and scope. It distinguishes from sibling search tools by emphasizing exact symbol lookup rather than broad search.

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?

The phrase 'specific symbol' implies use when the exact name is known, but it does not explicitly state when to use this tool versus alternatives like search_kernel_code. No exclusions or alternative tool references are provided.

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