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

Annotations already declare readOnlyHint and idempotentHint, covering safety and repeatability. The description adds valuable behavioral context: the population deduplication rule ('count each person once, regardless of technologies') and data vintage ('as of June 2021'). These are beyond what annotations provide, enhancing the agent's understanding of the data's meaning without contradicting any annotation.

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 two sentences, tightly packed with information. The core purpose (what it returns) is front-loaded, followed by critical behavioral notes and a parameter source hint. There is no filler or redundancy, making every sentence earn its place.

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 simple one-parameter read-only tool with an output schema, the description is complete. It explains the return content (technologies, population per tier), the data source and date, deduplication logic, and how to obtain the required hoconum. Combined with the existing output schema and annotations, nothing essential is missing for an agent to correctly invoke and interpret the 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 already provides a full description for the hoconum parameter, including an example and guidance to use fcc_search_providers. With 100% schema coverage, the baseline is 3. The description repeats the advice to use fcc_search_providers but does not add new semantic detail beyond what the schema already states, so it does not exceed the baseline.

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 a specific verb ('Returns'), a concrete resource ('national-level coverage profile for a specific holding company'), and the exact deliverables (technologies, population per speed tier). It clearly distinguishes from siblings by tying to hoconum and mentioning that fcc_search_providers is used to find valid hoconum values, making its purpose unique among the sibling tools.

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 explicitly instructs the agent to use fcc_search_providers to find valid hoconum values, providing a clear prerequisite and routing to the correct source for inputs. It does not explicitly state when not to use this tool versus other alternatives like fcc_get_coverage_summary, but the context (provider-specific vs. summary) is implied. This is clear but lacks explicit exclusions, so a 4 is appropriate.

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