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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the bar is lower, yet the description still adds genuine context beyond them: an empty result means a corpus gap rather than a nonexistent company, and the tool does not resolve arbitrary URLs. That result-interpretation guidance is exactly what an agent needs to avoid false negatives.

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?

Two short sentences, zero filler, with the primary capability front-loaded and the caveat appended. Every clause carries information an agent would otherwise have to guess.

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?

For a 4-param read-only lookup with annotations covering the safety profile and no output schema to explain, the definition is nearly sufficient. The remaining hole is pagination behavior (limit/cursor) and whether name matching is exact or fuzzy, which the description never addresses.

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?

Schema description coverage is 0%, so the description must carry parameter meaning; it covers only two of four (name, and domain via "exact website hostname", where the exactness note is a useful addition). Limit (max 5) and cursor pagination are entirely undocumented, leaving the agent unable to page through results from text alone.

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?

States a specific verb+resource ("Find known companies") and the two lookup keys ("by name OR exact website hostname"), which is enough to tell it apart from a singular lookup like get_company. It stops short of naming that sibling explicitly, so differentiation is implied rather than stated.

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 "exact website hostname" constraint and "never fetches arbitrary URLs" implicitly tell the agent this is a corpus lookup, not a live web fetch, and that a hostname must be exact. However, there is no explicit statement of when to prefer this over get_company, nor what to do when name and domain are both omitted.

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