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

With no annotations, the description carries the full burden and does well: it discloses immutability (append-only, hash-chained), signing, the 0.05 USDC cost, the 3/day/IP trial, and the exact payment-recovery path on 402. It omits what the created attestation returns, which is a small gap given no output schema.

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 tight sentences: purpose first, then pricing/limits, then the payment-retry procedure. No filler, and the most important information is front-loaded.

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 2-param, no-output-schema tool with no annotations, the description covers purpose, cost, rate limits, and the payment recovery path well. It could say more about the shape of the returned attestation or how to later verify it, but nothing critical to correct invocation is missing.

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%, so both params are documented, giving a baseline of 3. The description adds value by explaining the payment param's role in the 402 retry flow, linking the tx hash to a concrete recovery scenario rather than leaving it as a bare field.

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?

Names a specific verb (Create) plus a precisely characterized resource: a signed, hash-chained, append-only attestation defined as verifiable proof-of-existence. This clearly separates it from siblings like verify_attestation, attestation_pubkey, and hash_sha256, which serve different roles.

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 strong operational context (cost, free trial, 402 retry flow) but never states when to choose this over verify_attestation or hash_sha256. Usage is implied by 'proof-of-existence' rather than explicitly contrasted with alternatives.

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