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

Annotations already declare readOnlyHint/openWorldHint/idempotentHint, but the description adds substantial behavioral context: the exact verdict vocabulary, the crucial caveat that 'could_not_verify means the check did not happen... it is NOT evidence', the meaning of 'unsupported', and the pipeworx:// citation format. This is exactly the kind of nuance an agent needs beyond structured hints.

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 longer than average but front-loaded with query examples and a clear use statement. Every sentence contributes useful information, and the could_not_verify caveat is essential. Minor redundancy and a typo ('cover no source') prevent a perfect score.

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?

Even without an output schema, the description fully enumerates the verdict types, return contents (grounded value + citation + reasoning), and error semantics. It also explains fallback routing and why this tool replaces multiple sequential calls, making it complete for an agent to invoke correctly.

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 full schema descriptions, so schema coverage is 100% and the baseline is 3. The tool description itself does not elaborate on parameter usage, but the schema already explains claim and tolerance_pct clearly, including the tolerance range and default behavior.

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 concrete natural-language triggers ('fact check', 'verify the claim that…') and defines the tool as 'natural-language claim verification against authoritative sources' with a specific verb and resource. It also distinguishes itself from sibling research tools by describing a consolidated pipeline and routing for financial vs. other claims.

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 whenever the agent needs to check whether something a user said is factually correct' and explains the routing between the SEC EDGAR fast path and the grounded pipeline. It does not name sibling tools or list when-not-to-use scenarios, so it stops short of a 5.

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