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

Annotations already declare readOnly/idempotent/non-destructive and closed-world, so the safety profile is covered. The description usefully adds the return shape (top-N matches with score) and the cost metadata (10 credits, Tier 1), but says nothing about ranking mechanics, whether results are deterministic, or what happens when signs are omitted.

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 front-loaded sentences that state function and return value with no filler, followed by compact group/endpoint/cost metadata. Efficient and easy 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?

An output schema exists, so return-value detail is not required. However, for a 7-parameter tool with 0 required parameters, 29% schema coverage, and no usage guidance, the description leaves meaningful gaps about how to compose a call and when to prefer this over the sibling crystal tools.

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 29%, and the description compensates partially by naming the sign inputs (Sun/Moon/Asc) and intent keywords. It says nothing about limit, the fields compact-mode path syntax, or precision rounding, so the low-coverage parameters remain only partially explained.

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 verb (recommend) and resource (crystals) plus the scoring basis (natal Sun/Moon/Asc placements and intent keywords), which is more than a tautology. It does not explicitly contrast itself with the overlapping siblings astroway_esoteric_crystals_by_zodiac_sign and astroway_esoteric_crystals_by_purpose_purpose, so an agent must infer the boundary.

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 mention of natal placements and intent keywords implies when the tool applies, but there is no explicit when-to-use statement, no exclusions, and no pointer to the by-zodiac or by-purpose siblings that cover adjacent needs. Usage is inferable rather than stated.

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