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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds significant behavioral context beyond annotations: it explains the internal pipeline (SEC EDGAR fast path vs. grounded pipeline), defines the semantics of could_not_verify and unsupported, and warns that could_not_verify is not evidence for/against the claim. It does not mention rate limits or auth, but the added detail is substantial.

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 relatively long but every sentence earns its place: it front-loads with trigger phrases and purpose, then explains the two pathways, the return verdicts, and critical caveats. The structure is clear with semicolons and a warning section. It is appropriately detailed given the tool's complexity, though slightly verbose compared to a minimal two-sentence description.

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?

Given the tool's complexity (multiple claim types, multiple verdicts, error semantics) and lack of an output schema, the description provides complete context. It specifies the verdict values, the citation format (pipeworx://), the distinction between could_not_verify and unsupported, and the internal routing logic. An agent has enough information to select and invoke the tool 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?

Schema description coverage is 100%, so the baseline is 3. The description adds extra meaning for tolerance_pct by explaining the default (implied by wording, capped at 5) and its use in hallucination detection with set values 1–2. It also provides concrete examples for the claim parameter. This goes beyond the schema descriptions, justifying a 4.

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 the tool's function: natural-language claim verification against authoritative sources. It lists explicit trigger phrases ('Is it true that…', 'fact check') and distinguishes itself from siblings by focusing on fact-checking rather than research or data retrieval. The verb 'validate' plus the resource 'claim' is specific and unambiguous.

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 provides strong usage guidance: 'Use whenever the agent needs to check whether something a user said is factually correct.' It also differentiates two pathways (company-financial vs. any other factual claim) and explains when the tool replaces multiple calls. However, it does not explicitly name alternative sibling tools or specify when NOT to use it, so it falls 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.