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

Annotations already declare read-only, open-world, idempotent, non-destructive. The description adds significant behavioral nuance: the meaning of each verdict, especially that 'could_not_verify' means the check did not happen and must not be used as evidence, and that 'unsupported' means no source exists. It also discloses the failure error structure (verification_error{stage,detail}), going well beyond annotation 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 detailed but every sentence earns its place: trigger examples, usage conditions, routing logic, return verdicts, and critical caveats. It is front-loaded with the purpose and structured with clear sections (what it does, how it routes, what it returns, important caller notes).

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 fully explains return values (verdicts, grounded/structured values, citations, reasoning) and error semantics. It covers both financial and non-financial paths, caveats for failure modes, and efficiency benefits. Nothing major appears missing for an agent to invoke and interpret results 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 are fully described in the schema with examples and constraints (claim is a string, tolerance_pct is a number with range and default behavior). The tool description adds no new parameter semantics beyond referencing the tolerance math in passing, but schema coverage is 100%, so the baseline of 3 applies.

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 defines the tool's purpose: natural-language claim verification against authoritative sources, with example phrasings. It distinguishes itself from sibling tools by focusing on fact-checking with a verdict-based output and explains the two-path routing (SEC EDGAR for financial claims, grounded pipeline for all others).

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 states when to use it: 'Use whenever the agent needs to check whether something a user said is factually correct.' It also provides trigger phrases and explains that it replaces 4–6 sequential calls, implying it is the consolidated alternative. However, it does not explicitly name sibling tools to avoid, so it stops short of full when-not/alternatives guidance.

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