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

Annotations cover the safety profile (readOnlyHint, openWorldHint=false), and the description adds genuinely useful interpretive behavior: coverage depth is explicitly NOT a censorship score, and an absent/shallow country means under-measured, not unblocked. It also tells the agent to read current coverage from the response, which matters given there is no output schema.

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?

Front-loaded with the core definition, then the interpretive caveat, then the parameter hint — a sensible ordering with no filler sentences. It is slightly dense and the gating-gate clause could be tightened, but each sentence carries information.

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 by explaining what the metric means and instructing the agent to read current coverage from the response. It could go further on the shape of the returned coverage values, but for a single-optional-param read tool the essentials are present.

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% for the single country parameter, so the baseline is 3. The description adds meaning beyond the schema by stating that passing country=XX scopes to one country, implying the omitted case returns all countries' coverage — a default behavior the schema does not document.

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 resource (per-country measurement depth) and defines it concretely as 'how many distinct ISP networks (ASNs) Voidly has evidence from', including what it bounds (the >=3-network confirmed-block gate). It also explicitly distinguishes the metric from censorship scores, so an agent can separate it from siblings like get_censorship_index or get_atlas_score.

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?

It gives an implied usage ('read current coverage', 'pass country=XX for one country') but never states when to reach for this tool versus adjacent measurement-quality tools such as get_data_confidence, get_measurement_freshness, or get_category_coverage. The condition that selects it over alternatives is left to inference.

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