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

Goes meaningfully beyond the annotations: it discloses that a deterministic server-side skill (no model) answers, that out-of-scope asks are refused rather than guessed, that times use the server's UTC clock, and that the card is reachable via the 'open' link in the result. These are real behavioral facts an agent could not infer from readOnlyHint/openWorldHint alone.

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 bloated with self-promotional text ('proven skills with the most evidence', 'rated proven on a-to-mind.com from evidence...') that does not help an agent decide or invoke. The genuinely useful operational facts are buried mid-sentence rather than front-loaded.

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 two-parameter read-only tool with no output schema, it covers the essentials: nature of the answerer, refusal behavior, timezone handling, and where the full result lives. The main omission is any indication of what the text response looks like or how the 'open' link is surfaced.

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 explains 'ask' and the response_type enum. The description adds only example ask phrasing, which is marginal, and says nothing about the 3–600 character constraint beyond what the schema states.

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 purpose (answering constellation questions server-side) is only fully clear after reading the example asks; the opening clause 'Ask Verse's constellation skill' is framed as a marketing claim rather than a verb+resource statement. It also fails to differentiate from related siblings like moon_phase, meteor_showers, and skill_eclipse, which an agent might plausibly confuse it with.

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?

Usage is only implied through the example asks ('what's that constellation', 'where is Orion'). It states that unsupported asks are refused rather than guessed, which is useful, but never says when to pick this over the astronomy-adjacent siblings or what kinds of questions it explicitly does not take.

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