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

Annotations already establish readOnlyHint=true and openWorldHint=false, and the description is consistent with both — it is a read of a closed, Onepin-owned corpus. Beyond that it discloses the retrieval mechanism (questions are matched against English page descriptions) and the grounding obligation, which the annotations do not convey.

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?

Front-loaded with the resource and purpose, then a compact topic list, then the two behavioral rules. Every sentence earns its place, with only minor redundancy between the trailing sentence and the schema's parameter description.

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 a single required parameter, a 100%-covered schema, and an output schema that carries return-value detail, the description supplies what is needed: scope, topic coverage, matching behavior, and grounding rules. Only minor operational details (repeated calls, result-size handling) are absent.

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 baseline is 3. The description's guidance — pass a short English restatement, matched against English page descriptions — largely restates the schema's own parameter description rather than adding new semantics, so it does not exceed the baseline.

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 a specific resource — the official Onepin documentation pages — and the operation (answering a question about the service), then enumerates the covered topics (plans and credits, runs and downloads, dictionary, templates, API). It is clearly distinct from every sibling, all of which operate on workflows, runs, or voices rather than documentation. The verb is implied by the tool name rather than stated, which keeps it from a full 5.

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?

It gives usable context for when to reach for it (any question about what Onepin does) and a grounding constraint, 'Answer only from what it returns,' that tells the agent not to supplement from its own knowledge. No explicit when-not or alternative tool is named, but no sibling covers documentation, so there is little to exclude.

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