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

With no annotations, the description carries the full burden and mostly succeeds: it discloses the payment model (x402, EOA EIP-712 only, no ERC-1271/6492), the 64 KiB body cap, that timestamps and input facts are not authenticated, that the price is experimental, and the exact return vocabulary. It stops short of describing error handling, clock-skew behavior, or partial-failure semantics.

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?

A single dense paragraph with no filler; the return-status enumeration and limitations each earn their place. Leading with the pricing bracket rather than the purpose slightly buries the front-loaded value, but the overall size is appropriate.

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?

The enumerated return values partially compensate for the missing output schema, and the caveats cover the payment/auth surface. However, for a tool with 0% schema coverage, no annotations, and a nested records array, the description leaves the per-field contract (record_id, observed_at null, as_of format) underspecified relative to the calling complexity.

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 0%, so the description must compensate for the schema. It does explain the concepts behind the two parameters (per-record ttl_seconds and the as_of/clock reference), but it says nothing about record_id, the nullability of observed_at, timestamp formats, the 1000-record cap, or TTL bounds.

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 names a specific operation: evaluating supplied observation timestamps against a caller-declared TTL and server clock (or a supplied reference time), returning one of four named statuses. That is far more concrete than the name alone, though it makes no attempt to distinguish itself from the many sibling '*_check' verification tools.

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 use case is implied by the semantics (checking whether observations are stale against a TTL), but there is no explicit 'use this when...' guidance, no exclusions, and no routing to alternatives such as evaluate_deliverable or incident_timeline. An agent must infer the fit from the described behavior.

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