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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuine domain context: what a paran is, that it is a latitude not a location, twelve event pairs, and the distinction that minus-meridian-against-meridian is a shared right ascension rather than a paran.

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 before the technical elaboration. Some sentences are dense and philosophical ('not a place, a latitude'), but they earn their place by disambiguating the concept.

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. The description adequately conveys the technique and its scope; the only gap is the absence of explicit sibling routing, which is minor against the otherwise complete conceptual framing.

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%, so the schema already documents body, fields, and precision thoroughly. The description adds no parameter-level detail (syntax, defaults, units) beyond what the schema provides, making the baseline 3 correct.

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?

The description states a specific verb+resource: it computes latitudes where a fixed star and a planet are angular at the same moment, and frames it as Brady's tabulation. This distinguishes the star-planet scope well, though it never names the sibling astroway_geo_parans to clarify which paran tool to pick.

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?

Usage is implied rather than stated. The phrase 'not a place, a latitude' implicitly separates this from place-based geo tools like astroway_geo_acg, but there is no explicit when-to-use, when-not, or named alternative for the agent to route on.

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