fact_check

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

There are no annotations, so the description carries the behavioral burden. It discloses that the tool checks against current web sources and returns 'a verdict with supporting evidence', which conveys the main behavior. It does not mention potential limitations such as source reliability or how the verdict is formatted, but it gives enough context for a low-risk read operation.

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?

Three short sentences, each with a distinct job: define the operation, describe the output, and state when to use it. No filler or redundant restatement of the tool name.

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?

For a simple 2-parameter tool with no output schema, the description covers the core invocation: what input to provide, what it does, and what kind of result to expect. It falls short of full completeness only by not specifying the possible verdict categories or how to handle ambiguous claims, but these are minor for tool selection and invocation.

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%, and the schema already describes 'claim' and 'context'. The description adds only the 'specific claim or statement' framing, which mildly reinforces the claim parameter, but does not add meaningful semantics beyond 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?

States a specific verb ('Verify'), a specific resource ('a specific claim or statement'), and the method ('against current web sources'). This clearly distinguishes it from sibling tools web_search and deep_research, which are for broader search and deeper investigation.

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?

Provides an explicit condition for use: 'Use when you need to check if something is true, outdated, or misleading.' It does not explicitly name alternatives or when-not-to-use, but the 'specific claim' phrasing implicitly steers away from broad web_search or deep_research tasks.

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