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

Annotations already establish read-only, closed-world, non-destructive, so the closing 'Read-only, free' adds little. The description does contribute real behavior beyond annotations: the held-state prohibition, the caveat-attachment requirement, and the empty-result interpretation. Permission or scope details are not covered, which keeps this below a 5.

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 definition is front-loaded with the resource identity and record shape, then moves to usage rules, then edge cases in a logical order, with no filler sentences. The only near-waste is 'Read-only, free,' whose read-only half restates the readOnlyHint annotation.

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 carries the burden of describing the return shape, and it does so field by field (claim sentence, number with unit, keywords, caveat) plus the held status. For a zero-parameter read tool, an agent has everything needed to fetch and correctly use the result.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate; the baseline for a zero-parameter schema applies. The description instead spends its words on record semantics, which is the right allocation.

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 first sentence names the resource precisely ('the claim library') and defines what each record contains (one-sentence claim, number with unit, relevance keywords, self-interested caveat), which no sibling such as get_business_context or get_voice_profile provides. An agent can tell immediately that this is the source of quotable numbers, not generic context.

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 states the triggering condition explicitly ('when your user's writing needs a number about this product'), imposes a hard usage rule ('Never quote a claim without its caveat'), and declares an exclusion ('a claim marked held is NOT for use'). It even pre-empts a false-negative read with 'an empty library is an answer, not an error.'

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