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

Goes well beyond the readOnly/openWorld annotations by warning that the score is the share of anomalous OONI measurements over a rolling window, not a measure of how censored a country is, and that the response update time is not when measurements were observed. These are non-obvious semantic traps that would otherwise cause misreported answers.

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 use case, then layered caveats, with no filler sentences. It is dense — four separate disclaimers run together in one block — but each earns its place by preventing a specific misinterpretation.

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?

There is no output schema, and the description compensates by enumerating the returned fields and their meaning plus the rolling-window semantics. For a single-parameter, read-only lookup, nothing needed to call or interpret the result is missing.

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 already 100% (two-letter ISO code, pattern-constrained, required). The description adds only the emphasis that it is exactly one code, restating what the schema enforces; the baseline 3 for a fully documented parameter 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?

States a specific verb and resource: it returns Voidly's country-level censorship index entry for one two-letter country code, and enumerates the fields (status level, score, OONI anomaly rate, measurement count). It also draws an explicit boundary — 'a country-level signal, not a check of one website' — so an agent can distinguish it from any per-site capability 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 questions ('is the internet censored in Iran', 'is X blocked in Y') and an explicit exclusion (no per-site test; unmeasured sites are unknown, not accessible). It does not name or route to any of the sibling tools (voidly_incident_stats, voidly_measurement_summary), so the alternative-selection guidance is implied rather than complete.

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