A*C*G Lines Near a Point

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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely new operational context: the 50-credit Tier 3 cost, the POST /v1/acg-zones endpoint, and the fact that each returned line carries an angular distance. It stops short of auth or rate-limit notes, but with annotations carrying the safety profile this is solidly above baseline.

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 core behavior front-loaded, followed by structured group/endpoint/cost metadata. Little waste, though the endpoint and group lines contribute less than the opening sentence.

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 explanation is rightly omitted, and cost/endpoint are disclosed. The notable gap is that the schema's dual coordinate requirement (natal birth data plus a separate 'point') goes unexplained, and there is no routing hint among the many geo_* siblings — for a 50-credit call, that is worth a sentence.

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 date, time, coordinates, timezone, ayanamsa, house system and the point/radiusDeg block. The description only echoes radiusDeg and 'one location', and that phrasing is mildly ambiguous given the schema requires both birth-data coordinates and a separate point object — it does not explain the relationship between the two.

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?

Names the concrete resource (A*C*G lines), the spatial scope (within radiusDeg of a point), and the payload (angular distance per line), plus a memorable tagline ('what runs over this city'). It does not, however, distinguish itself from nearby siblings such as astroway_geo_acg, astroway_geo_acg_line_report, or astroway_geo_local_space, so an agent cannot tell from the text alone which geo 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?

The tagline 'what runs over this city' strongly implies the query pattern — locate planetary lines crossing a given location — but there is no explicit when-not guidance, no named alternative, and no note about when a full ACG map or line report would be preferable.

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