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

Annotations already declare openWorld (external Bitcoin anchoring) and non-idempotent write behavior, so the bar is lower, yet the description still adds that the notary is free and that a receipt code plus link is produced per fingerprint (batch semantics). It omits any mention of irreversibility or rate limits, which would have pushed it higher.

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 short sentences, front-loaded with the core action, then the input contract, then the return shape. No filler or repetition.

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 three-parameter tool with no output schema, the description covers the action, the input precondition, and the shape of the return (receipt code and link). The unresolved api_key parameter — whose presence is not explained anywhere — is the main remaining gap.

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 only 33% — only 'label' is documented. The description compensates for the most important gap by specifying the digest format (SHA-256, 64 hex) and clarifying that only fingerprints are transmitted, but it says nothing about api_key or the label parameter's role. Partial compensation warrants a 3.

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 specific verb and resource — timestamping SHA-256 fingerprints in Bitcoin via sebbi.pro — with concrete format constraints (64 hex). It implicitly separates itself from retrieval siblings like sebbi_notary_receipt and sebbi_forever_proof by framing this as the submission side, but no sibling is named explicitly.

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?

'Hash the file or text yourself and send only the fingerprint' is real operational guidance: it tells the agent exactly what input to prepare before calling. There are no stated exclusions or named alternatives, so it stops short of the 5-level routing guidance.

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