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

With no annotations, the description fully carries the burden. It transparently states the tool calculates longitudes only (no houses) and requires no birthplace. It does not disclose potential side effects or rate limits, but these are unlikely for a read-only computation. The return structure is partially described.

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?

The description is three sentences, each adding distinct value: purpose, return details, and a key constraint (no houses, no birthplace). It is front-loaded with the core verb and resource, making it efficient and easy to parse.

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?

Despite lacking an output schema, the description gives a reasonable overview of what is returned (per body longitudes and the solar arc). It omits the list of celestial bodies and the exact structure (e.g., keys), but for a specialized astrological tool, this is likely sufficient for an agent familiar with the domain. The absence of an output schema is partially compensated by the description.

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%, so the schema documents all parameters. The description reinforces that 'date' and 'target_date' are needed and mentions 'no birthplace is needed', but adds little semantic value beyond the schema's descriptions. The zodiac parameter is covered by the schema enum.

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 clearly states the tool calculates secondary progressions (day-for-a-year) and solar-arc directions for a natal chart to a target date. It specifies what is returned (longitudes per body) and what is not (houses), distinguishing it from sibling tools like 'directions' or 'transits' which may focus on other techniques.

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 description does not explicitly state when to use this tool versus alternatives such as 'directions', 'transits', or 'returns'. It implies use for progressions and solar-arc but lacks guidance on exclusions or prerequisites, leaving the agent to infer context.

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