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 still adds real value by disclosing the credit cost (20 credits, Tier 2), the endpoint, and the non-obvious return behavior that rising/setting curves arrive as several disjoint segments and all are returned.

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 front-loaded sentences cover the payload, and the bracketed group/endpoint/cost block is compact and genuinely useful metadata rather than filler. No redundancy or wasted sentences.

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?

For a single-line report tool with a rich output schema, the description covers scope, response shape, the disjoint-segment caveat, and cost. The main missing piece is routing guidance relative to the overview sibling tools, which the description never addresses.

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 embedded schema is exceptionally detailed (timezone/offset semantics, houseSystem letters, field paths, precision). The description adds no parameter-level meaning beyond that, so the baseline 3 applies.

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 reports on a single A*C*G line, enumerating its geometry, the life areas it touches with weight and polarity, and the interpretation text for one planet-angle pair. This clearly distinguishes it from the whole-map sibling astroway_geo_acg by scope ('One line in full'), though no sibling is named explicitly.

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 only implied: the phrase 'One line in full' suggests this is the drill-down for a single line after locating it, but there is no explicit when-to-use statement, no prerequisites (birth data + planet/angle are required), and no named alternative such as astroway_geo_acg for the overview case.

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