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 categories of data returned (carrier type, country, FRN/RMD, Canadian registration/contact), which is more than the name. However, it says nothing about behavior for an unknown OCN, error modes, rate limits, or that the call is a read-only lookup with no side effects.

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 sentences, front-loaded with the action and resource, then the usage cues. No filler or 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?

No output schema exists, and the description compensates reasonably by enumerating the field families returned. For a single-key lookup with fully described parameters this is nearly complete; only error/empty-result behavior and auth expectations for api_key are unaddressed.

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 coverage is 100% and the description only repeats the 4-character OCN format already documented in the schema. It adds no new syntax, casing, or api_key guidance beyond what the parameter descriptions provide.

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 and resource ('Fetch carrier profile details for a 4-character OCN') and implicitly scopes it to a single-carrier lookup, which distinguishes it from search_carrier_profiles_by_frn and search_carrier_profiles_by_rmd_id. An agent can tell what this returns without opening the schema.

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?

Gives concrete triggering conditions ('user asks who an OCN belongs to', 'wants carrier type/country', 'needs FCC FRN/RMD or Canadian registration fields'), which is clear usage context. It does not explicitly name the sibling search tools as alternatives or state when not to use it.

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