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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered. The description adds real behavioral context not in annotations: the call returns claim checks plus groups of related figures and is a discovery step that requires a follow-up ('fetch the matching claim check, or open the group'). It stops short of saying what happens when no match is found.

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 trigger ('Before quoting an AI statistic') is front-loaded with concrete examples that make the intent immediately legible. The middle sentence about claim checks and groups is slightly tangled in phrasing but still earns its place by describing the return.

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 returns and does so at a high level, plus it explains the follow-up flow to the matching claim check or group. Missing only edge-case behavior (e.g., when nothing matches), which is a minor gap for a lookup tool.

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?

Zero input parameters, so the schema baseline of 4 applies. The description adds nothing about parameters because there are none to document.

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+resource (check an AI figure/statistic) and immediately scopes it to provenance: origin, who was asked, what it covers. It also contrasts itself with the sibling check_vendor_claim, so an agent can pick between the two without opening a schema.

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?

Explicitly names the domain of use ('figures from surveys, reports and the press') and hands off the excluded case ('For a claim a vendor makes about its own product, use check_vendor_claim'). This is a clear when-to-use plus when-not-to-use-with-alternative, the top of the scale.

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