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

With no annotations provided, the description carries the full burden of behavioral disclosure. It conveys that this is a read-only style analysis tool that returns a verdict, reasoning, and sources, and that it compares against a 'dated official record.' It does not enumerate edge cases or out-of-scope claims, but for a simple look-up-verification tool the key behavior is disclosed.

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 compact and well-structured. The action and return value are front-loaded, the four covered figures are packed into one useful scope sentence, and the usage instruction is a short final sentence. No sentence is redundant.

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 one-parameter tool with no output schema, the description provides enough to invoke it correctly: what the user claim should be, what the tool checks, what it returns, and when to use it. It doesn't describe failure behavior for claims outside the four covered figures, but nothing essential is missing for normal calls.

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 only parameter, `claim`, is already fully described in the input schema with an example ('under $800 is duty free'). Since schema description coverage is 100%, the description does not need to add much. It reinforces that the input should be a user-quoted number, but adds no new meaning beyond the schema.

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 opens with a specific verb ('Fact-check') and a specific resource ('a circulating claim about US import duties against the dated official record'). It clearly distinguishes itself from the sibling tools by focusing on verifying a user-quoted number, not on rulings, calculation frameworks, or rule lookups. It also states the return shape up front: a verdict, why, and the sources.

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 description explicitly says 'Use this when a user quotes a number for US imports,' which gives a clear trigger for tool selection. It doesn't spell out when-not-to-use or name sibling alternatives, but the stated scope of covering the four recurring figures provides a reasonable decision boundary.

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