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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds a genuine scope boundary beyond the structured fields: it explicitly disclaims external ephemeris recomputation, telling the agent what the audit does NOT verify.

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 tight sentences with the scope statement front-loaded and the disclaimer second. Nothing is padded, though the dense enumeration is slightly hard 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?

An output schema exists, so return values need not be explained. However, for a 9-parameter audit tool with 33% schema coverage, the description leaves the input contract and the when-to-use-vs-siblings question substantially unaddressed.

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 only 33% across 9 parameters, so the description is expected to compensate, yet it mentions no parameter at all. The agent gets no help on the place-vs-coordinates anyOf, the timezone requirement, or birthTimeAccuracyMinutes, which is the parameter most relevant to a sensitivity audit.

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 enumerates the resources it audits: engine certification, timezone provenance, conventions, and boundary distances. This clearly reads as a calculation-provenance verifier. It does not, however, explicitly distinguish itself from near-neighbors like explain_chart_sources, get_validation_report, or compare_conventions.

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?

'...before interpretation' implies the usage context (run prior to reading a chart), which is a meaningful hint. But it names no alternatives, no prerequisites, and no conditions under which another audit/validation sibling should be preferred.

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