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

Annotations already declare readOnly/openWorld/idempotent, but the description adds critical failure semantics: could_not_verify means the check did not happen and carries verification_error{stage,detail}, must not be shown as evidence; unsupported means no source coverage. It also enumerates the full verdict list and explains the two execution paths, going well beyond annotations.

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 front-loaded with trigger examples and a clear purpose sentence, then efficiently covers the two execution paths, return structure, a critical callers caveat, and efficiency context. Every sentence serves a purpose with no filler or redundancy.

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 assumes full responsibility for describing return values: it lists all six verdicts, explains the edge cases (could_not_verify vs unsupported), and mentions the citation and reasoning. Given the tool's two pipeline complexity and the presence of detailed annotations, the description is complete enough for an agent to select and invoke it 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?

The input schema provides 100% coverage with detailed descriptions for both parameters, including tolerance_pct's range, semantics, and default. The tool description adds no additional parameter-specific meaning beyond what the schema already provides, so the baseline 3 is appropriate.

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 natural-language examples and explicitly defines the tool as 'natural-language claim verification against authoritative sources.' It clearly identifies the action (verify/check), the resource (factual claims), and scope, and distinguishes itself by mentioning it replaces 4–6 sequential calls, differentiating it from lookup/research siblings.

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?

'Use whenever the agent needs to check whether something a user said is factually correct' provides explicit when-to-use guidance. It also describes the two processing paths (SEC EDGAR fast path vs grounded pipeline) and clarifies that could_not_verify is not evidence, which informs correct handling. However, it does not name sibling tools or give explicit when-not-to-use scenarios.

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