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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds that it returns new houses and planet house positions, plus a cost tier, which is modest extra context; with an output schema present, return-value disclosure is not strictly required.

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 lead with the core action and follow with the return content, and the metadata block (group, endpoint, cost) is compact and useful. No filler, though the sentence could be slightly more front-loaded on the 'what changes'.

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?

With a full output schema, complete annotations, and 100% schema coverage, the description only needs to convey purpose and scope, which it does. The main shortfall is the lack of sibling differentiation within a very crowded geo_* namespace.

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 the natal/target structure, the timezoneOffset semantics, and the houseSystem letters. The description only loosely implies the target coordinates ('different lat/lng') and adds nothing the schema does not already state, 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 and resource ('Recalculate a natal chart') and pins down the exact operation ('same birth moment, different lat/lng'), so the agent understands this is a relocation, not a fresh chart. It does not, however, name or contrast any sibling such as astroway_geo_local_space or astroway_geo_geodetic, which an agent scanning the large geo_* family would need.

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 phrase 'same birth moment, different lat/lng' implies the usage scenario, but there is no explicit when-to-use or when-not-to-use guidance and no named alternative. With ~15 sibling geo tools, the absence of routing guidance is a real gap.

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