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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds the return content (angular distance to each line) and the operational cost (50 credits, Tier 3), which is useful context. It does not, however, describe result ordering, line-count limits, or what happens at the radius boundary.

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 constraint and return content front-loaded, followed by a compact metadata block. Nothing is wasted and the essential information comes first.

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 shape needn't be explained, and annotations cover safety. The definition is nearly complete for a read-only query tool; the remaining gap is sibling disambiguation within the crowded geo/ACG group, which the description leaves to inference.

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 carries the parameter documentation, including the detailed timezone/ayanamsa/houseSystem notes. The description only echoes radiusDeg without adding syntax, units, or default meaning. Baseline 3 is correct when the schema does the heavy lifting.

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+resource: A*C*G lines passing within radiusDeg of one location, plus the angular distance returned. The colloquial gloss "what runs over this city" pins the intent. However, it does not differentiate itself from the dense ACG sibling family (astroway_geo_acg, astroway_geo_acg_line_report, astroway_geo_acg_best_places), so an agent must infer which one 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 only implied by the phrase "what runs over this city" and the presence of a radiusDeg bound. There is no explicit when-to-use vs. when-not, and no named alternative among the many ACG siblings. Adequate but with clear gaps.

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