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

Annotations already declare this a read-only, idempotent, closed-world computation, so the safety profile is covered. The description adds genuinely new behavior: the default year and default location fallbacks, and that the response spans multiple years rather than a single moment. It says nothing about what happens when birth time is unknown, though the schema allows omitting 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?

It is a single dense sentence with three nested parentheticals, which packs a lot in but reads awkwardly and buries the output description in a trailing clause. Nothing is truly wasted, but restructuring into purpose-then-output sentences would make it easier to scan.

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 13-parameter tool with an output schema, the description covers the core concept, defaults and output content, which is adequate. The notable gap is the unknown-birth-time case and the coordinate inputs, though the output schema and per-parameter schema text offset some of that.

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?

With 62% schema coverage across 13 parameters, the schema carries most of the load, including the lat/lon/tz vs place alternation and the date/range constraints. The description contributes default semantics that the schema does not state (year defaults to current year, place defaults to birth place, return_place overrides it), but it ignores house_system, lang, return_tz/return_lat/return_lon and the optional time entirely.

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 precisely what is computed (the exact minute the Sun returns to its natal position, plus that moment's chart with planets, ascendant and houses) and what else is returned (the returns of following years). It is clear and specific, but it never names the sibling it differs from, so an agent cannot tell from the text alone why to pick this over planet_returns or birth_chart.

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?

Defaults are mentioned parenthetically (this year by default, place of birth by default), which hints at typical usage, but there is no explicit statement of when to use this tool, when not to, or which sibling covers adjacent needs such as natal charts, planetary returns or transits. The agent must infer the use case from the purpose sentence alone.

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