check_coverage

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

Annotations already cover safety (readOnly, idempotent, not open-world). The description adds meaningful non-obvious behavior: it discloses credential variable names but never values, which tells the agent the output is safe to surface, and it frames the tool as capability discovery for diagnosing sparse results.

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, no filler. The capability summary comes first and the usage trigger last, which is the right front-loading for a diagnostic tool.

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?

With no output schema, the description must convey what comes back, and it does so at the right altitude: sources, credential names, and returnable data. It does not explain how the optional country parameter reshapes that output, a minor gap for a zero-required-parameter 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?

Schema description coverage is 100% and the single country parameter is documented there, so the schema carries the load. The description never mentions country or how it scopes the coverage report, adding no meaning beyond the schema.

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 (Report) and enumerates exactly what it reports: enabled data sources, configured credentials (names only), and current server return capability. This is clearly distinguishable from all sibling lookup tools, which retrieve entity data rather than diagnostics.

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?

"Call this first if a lookup returns less than expected" gives an explicit trigger condition, which is genuinely actionable. It stops short of naming which siblings' failures should prompt it, but the diagnostic framing makes the alternative path obvious.

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