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

Beyond the annotations (read-only, open-world, idempotent), the description discloses the two-pipeline behavior, the verdict types, and crucially explains that could_not_verify means the check did not happen and must not be shown as evidence. This is critical behavioral nuance not inferable from annotations. No contradiction.

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 lengthy but densely informative, with a clear structure: examples, when-to-use, routing logic, return details, and caveats. Each sentence contributes essential information, though it could be tightened for brevity.

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 detailing the verdict enum, the presence of a pipeworx:// citation, and the error semantics of could_not_verify/unsupported. It also explains the two processing paths for different claim types, making it sufficiently complete for a complex 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?

Both parameters have schema descriptions (100% coverage), but the description adds more: tolerance_pct overrides the tolerance implied by the claim wording, with a default capped at 5 and a recommendation to set 1–2 for hallucination detection. Claim gets example formats. This adds meaningful guidance 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 clearly states this tool verifies natural-language factual claims against authoritative sources, with explicit example phrasings ('fact check', 'verify the claim that…'). It distinguishes itself from sibling search/ask tools by focusing on claim verification and by mentioning it replaces multiple sequential calls.

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 explicitly says 'Use whenever the agent needs to check whether something a user said is factually correct' and explains the routing for company-financial vs other claims. It also notes the tolerance_pct usage for hallucination detection. It doesn't explicitly name alternative tools to avoid, but the when-to-use is clear.

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