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

Annotations already indicate read-only, idempotent, non-destructive, and open-world behavior. The description adds valuable behavioral context: the operation is deterministic, it reports stale and missing-time evidence without claiming external truth, and it discloses that the resource is paid with a specific x402 price. This goes beyond the annotations and sets appropriate expectations about the tool's epistemic limits.

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 and front-loaded with the core purpose, followed by usage guidance and cost disclosure. Each sentence contributes meaningful information, with only a minor grammatical hiccup ('when determine'). Overall it is appropriately sized and structured for quick parsing.

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-parameter tool with no output schema and minimal schema descriptions, the description covers purpose, behavioral semantics, usage boundaries, and cost, which is useful. However, it omits crucial parameter construction details and does not explain the output structure beyond 'reports stale and missing-time evidence.' The tool is adequately scoped for selection but not fully self-sufficient for 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?

The input schema has 0% description coverage, so the description must compensate, but it only gives high-level hints: records contain observed timestamps and maximum-age requirements, and now is a clock reference. It does not define the shape of records, how maximum-age constraints are expressed, or the expected timestamp format for now. An agent would still struggle to construct a valid payload without external knowledge.

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 states a specific verb and resource: deterministic freshness evaluation for supplied records using observed timestamps, maximum-age requirements, and a clock reference. It clearly goes beyond the title by explaining the mechanism and the nature of the output. This makes the tool's purpose distinct even among a large sibling list with no similarly named freshness checker.

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 says to use this tool when deciding whether data an agent is about to act on is fresh enough for a caller-defined technical SLA. It also gives explicit negative guidance, instructing the agent not to use it for unrelated general knowledge or unsupported legal, identity, sanctions, fraud, contractual, or regulatory adjudication. This gives both clear when-to-use and when-not-to-use boundaries.

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