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 adds value beyond them by disclosing the return shape (title, URL, section list, read_doc argument) and the auth requirement ("No API key needed"), which is meaningful operational context for an agent.

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?

Three short sentences, front-loaded with the core action and scope, then the return shape, then the routing rule. Every sentence carries distinct information; there is no filler or restatement of the name/title.

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 no output schema, the description compensates by describing the returned fields and the downstream argument for read_doc. Combined with 100% schema coverage and rich annotations, an agent has everything needed to select and invoke the tool correctly.

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 language, limit and query are already fully documented in the schema, including the enum values and defaults. The description adds no parameter-level detail (no hint about syntax, quoting, or which language setting to prefer), 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?

States a specific verb and resource ("Search the AstroWay guides") and enumerates the covered content domains (authentication, credits, error codes, field formats, agent setup, product pages), which lets an agent tell it apart from sibling tools without opening a schema. It also explicitly names the sibling it is not, find_endpoint.

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?

Gives an explicit negative condition plus the alternative: "For 'which endpoint do I call' use find_endpoint instead, which also gives the price." That is a concrete when-not-to-use rule with a named replacement, which is exactly what routing requires.

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