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

Annotations already declare readOnly, idempotent, and non-open-world behavior, so the safety profile is covered. The description adds genuinely new context: the hard 92-day window cap and the '(API Pro)' access requirement, which an agent needs before invoking it.

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?

A single, front-loaded sentence that enumerates the payload contents without filler. The trailing parenthetical is the only element that slightly interrupts the flow.

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 nested-object tool with no output schema and sparse schema descriptions, the definition is only partially sufficient: it lists returned data categories but does not explain the default `from` behavior, the response shape, or how the large event list is delivered.

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 only 33%, so the description should compensate, but it only loosely echoes the 'up to 92 days' window already documented on the `to` field. The `from` parameter and the nested birth fields (notably latitude/longitude/timezone) receive no additional clarification.

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 names a specific resource (transit events) and spells out the contents: transit-to-natal aspects by date, sign ingresses, and stations. It is clearly distinct from natal_chart or synastry, though it does not explicitly contrast with the nearby sibling daily_transits.

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?

There is no guidance on when to choose this over daily_transits or sky, nor any stated prerequisites beyond the parenthetical '(API Pro)'. The 92-day window hints at scope but not at tool selection.

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