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

Beyond the annotations (readOnlyHint, openWorldHint, idempotentHint), the description adds rich behavioral context: the two execution paths (SEC EDGAR fast path vs. grounded pipeline), the exact meaning of could_not_verify with verification_error{stage,detail}, and the crucial warning not to present could_not_verify as evidence. It also clarifies unsupported as a coverage outcome, fully disclosing edge-case behavior.

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 dense but efficiently organized: trigger phrases, purpose, routing logic, return contract, and caller caveats are front-loaded. Every sentence contributes operational value (e.g., 'Replaces 4–6 sequential calls'), with no filler or redundant repetition of annotations/schema. It is long but each clause earns its place.

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 the return value structure: verdict, grounded/structured actual value with pipeworx:// citation, and reasoning. It covers the critical distinction between could_not_verify and unsupported, the source-routing logic, and the efficiency advantage, making the tool's behavior predictable for an agent even in odd edge cases.

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 already provides 100% coverage with detailed descriptions for both claim and tolerance_pct, including how tolerance_pct overrides the implied tolerance and its default cap. The description does not add new parameter-level semantics beyond the schema; it only reinforces the routing logic already present in 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 identifies the tool as natural-language claim verification against authoritative sources, lists concrete trigger phrases, and enumerates the verdict types. It distinguishes itself from siblings by focusing on fact-checking ('confirm or refute') and by explicitly mapping financial claims to the structured SEC EDGAR path and other claims to the grounded pipeline, making its scope unmistakable.

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 'Use whenever the agent needs to check whether something a user said is factually correct' and provides a detailed routing guide for financial vs. non-financial claims. However, it does not explicitly name alternative tools or state when NOT to use this tool, so it falls short of the highest bar for usage guidance.

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