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

Annotations already declare non-read-only, non-idempotent, open-world behavior; the description adds nothing behavioral beyond a credit cost and endpoint. Critically, it never explains what 'stream' means here (SSE, long-poll, chunked response) or how repeated calls behave, despite idempotentHint=false.

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?

Extremely short and front-loaded: the purpose sentence leads, with group, endpoint and cost as compact metadata tags. Nothing is padded, though the terseness is achieved partly by omitting load-bearing content.

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 no explanation, and cost/endpoint metadata is present. However, for a streaming tool requiring a full birth-data body, the description says nothing about delivery mechanics or how the 'next N hours' window interacts with the required natal data — a real gap.

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 100% and the nested body description already documents date/time/coordinates/timezone rules in depth, so the schema carries the load. The description's 'N hours' hints at the hours field but adds no syntax or semantics beyond that, matching the baseline 3.

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 resource and condition — 'natal-transit hits within next N hours' — which is clearly distinguishable from stream_positions or stream_ingress. It does not name a sibling or scope boundary, so it falls short of 5.

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?

No when-to-use guidance is given. With siblings like astroway_webhooks_transit_trigger and astroway_stream_retrograde_alerts in the same family, the agent must guess whether streaming vs. webhook delivery is the right choice; the [Group] tag is metadata, not guidance.

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