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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world behavior. The description adds a useful limitation ('does not claim an external ephemeris recomputation') and pre-interpretation scope, but omits auth requirements, failure behavior, and data-source details beyond that caveat.

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 what the tool checks, followed by a clarifying caveat. No filler or repetition, and the structure is easy to scan.

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?

Output schema exists and annotations cover safety, so return values need not be explained. But for a 9-parameter audit tool with 33% schema description coverage, the description omits parameter semantics and input-combination rules, leaving an agent under-informed about correct invocation beyond the general purpose.

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 only 33% across 9 parameters. The description mentions timezone provenance but does not explain name, date, time, place, latitude, longitude, timezoneOffset, or birthTimeAccuracyMinutes, nor does it clarify the place-versus-coordinates input pattern. It fails to compensate for the low schema coverage.

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 ('Checks') and specific resources (engine certification, timezone provenance, conventions, boundary distances). It distinguishes from external ephemeris recomputation, but does not explicitly differentiate from sibling audit/validation tools such as audit_prediction_claim or get_validation_report.

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?

Implies usage 'before interpretation' and states it does not recompute an external ephemeris, which gives some when-to-use context. However, it provides no explicit alternatives, exclusions, or conditions for choosing it over related audit and validation siblings.

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