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

With no annotations present, the description carries the full burden and does so: it discloses cost (0.01 USDC on Base), the x402 handshake including the isError/402 structuredContent shape on the unpaid call, that results are signed by neo and logged, and that anchoring is daily on Bitcoin. These are exactly the non-obvious traits an agent needs before invoking a paid mutation.

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?

Front-loads the value proposition in the first clause and then packs payment mechanics into compact sentences with no filler. Dense but every sentence carries information; slightly overloaded with endpoint URLs and metadata syntax in one block.

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?

No output schema and no annotations mean the description has to cover both behavior and returns, and it covers the payment round-trip well. However it omits any description of the receipt contents/return shape beyond 'signed receipt with a position in a public log', and leaves the note parameter entirely unaddressed.

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. It implies sha256 is the digest being timestamped but never gives format expectations (hex, length, prefix), and the 'note' parameter is never mentioned at all despite being one of only two params.

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 concrete verb and resource — timestamp a sha256 to prove existence at a point in time — plus the mechanism (OpenTimestamps, Software Heritage, Bitcoin anchoring). It's not explicitly differentiated from the neighbouring paid_proof_of_publication sibling, which is the only thing keeping it from a 5.

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?

Gives a clear operational path: call without payment to receive the 402 requirements, then retry with the signed payment in _meta['x402/payment'], and points to a free sample endpoint as an alternative for testing. It doesn't say when to prefer this over paid_proof_of_publication, but the payment mechanics are laid out step by step.

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