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

Beyond annotations (readOnly, openWorld, idempotent), the description adds critical behavioral detail: the distinction between 'could_not_verify' (check did not happen) and 'unsupported' (no source found), plus the warning not to treat 'could_not_verify' as evidence. It also discloses the fallback pipeline behavior and return structure, far exceeding annotation coverage.

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 fairly long but each sentence earns its place: trigger examples, use case, routing, return format, and crucial error semantics. It is front-loaded with the most recognizable trigger phrases, making it easy to match. Slightly verbose but appropriate given tool complexity.

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 carries the burden of explaining return values, which it does fully: lists the verdicts, mentions the 'grounded or structured actual value with pipeworx:// citation, and reasoning'. It also explains the two distinct failure modes, covering the complete behavior for all plausible inputs. This is a complete description for an agent.

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 coverage is 100%, and both parameters are already described in detail in the input schema. The description does not add substantial new semantics beyond what the schema states; it merely references tolerance in passing. This fits the baseline of 3 for high schema coverage.

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 trigger phrases and explicitly states it performs 'natural-language claim verification against authoritative sources'. It clearly distinguishes the tool from siblings by focusing on fact-checking with a verdict output, and even notes it replaces 4–6 sequential calls, making its scope 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?

It provides explicit when-to-use guidance: 'Use whenever the agent needs to check whether something a user said is factually correct.' It also outlines two routing paths (company-financial vs. other claims), giving concrete context. However, it does not explicitly name alternative tools or give when-not-to-use exclusions, stopping 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.