Check a claim against source context

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds value beyond that by disclosing what the tool detects (overconfident claims, unverified citations, unsourced statistics, contradictions) and what it returns (grounded, confidence, riskLevel, risky statements, recommendation). This gives the agent a clear behavioral contract without contradicting the annotations.

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 compact yet complete: three sentences cover purpose, usage timing, parameter mapping, and return values. Every sentence contributes, and the primary purpose is front-loaded. No filler or redundancy.

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 two-string-parameter tool with no output schema, the description compensates well by enumerating the return fields and clarifying the confidence scale ('1 = fully grounded'). It covers the essential invocation details and expected results. It lacks only minor edge-case details like empty-context behavior, which the schema's minLength already guards against.

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 both claim and context already have meaningful schema descriptions. The tool description loosely restates the roles ('Pass the generated text as `claim` and the material it should be based on as `context`') but does not add significant detail beyond the schema. The baseline of 3 applies because the schema does the documentation heavy lifting.

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 a specific verb and resource: 'Verify whether a claim or generated answer is grounded in a given source text.' It uniquely positions this tool against sibling tools like detect_pii, scan_injection, and check_safety, which address different concerns. The grounding/hallucination focus is 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 gives clear when-to-use guidance: 'Use this after producing a summary, answer, or extraction from documents, search results, or retrieved context to catch fabricated facts before presenting them.' This establishes the context and timing but does not explicitly name sibling alternatives or state exclusions, so it stops short of a full 5.

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