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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds no misleading side effects and implies a safe lookup operation. It does not elaborate on performance or external dependencies, but the annotations cover the key behavioral aspects.

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, combining the core purpose, an illustrative example, and the practical use case without unnecessary verbosity. All sentences contribute to understanding the tool.

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 description explains both the return content (title plus sibling codes) and the intended use case, which is sufficient given there is no output schema. It does not specify every edge case, but it gives enough context for an agent to decide when to invoke this 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 schema already provides 100% coverage of both parameters with clear descriptions. The description adds context for the `siblings` parameter via the example, but does not substantially go beyond the schema, so a baseline score is appropriate.

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 clearly states the tool looks up one exact 7-character ICD-10-PCS code and returns its title plus sibling codes, with a concrete example. It distinguishes itself from a general search by emphasizing exact code lookup and sibling expansion.

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 description explains the intended use case—finding alternatives to an already-known code—and gives an example with the `siblings` parameter. It does not explicitly contrast with `search_icd10pcs`, but the exact-match framing makes the usage clear enough.

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