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

With no annotations provided, the description carries full burden for behavioral transparency. It discloses that the tool is paid (~$0.006) and anchors a digest on-chain, implying a mutation/transaction. It does not reveal what happens on failure, whether the proof is returned immediately, or any side effects. The cost disclosure is useful, but more detail on behavioral traits (e.g., idempotency, latency) is needed.

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 a single sentence with no wasted words. It front-loads the cost indicator ('PAID') and clearly states the core action. Every word adds value.

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?

Given the tool complexity (3 parameters, paid mutation, no annotations), the description is minimally adequate but incomplete. It lacks details on parameter semantics, return values (despite output schema existing, the description doesn’t clarify what the proof contains or how to use it), and error conditions. The output schema may partially compensate, but the description should still contextualize the result.

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 three parameters. It only mentions 'SHA-256 digest' in the purpose, which loosely relates to the required 'digest' parameter, but does not explain format (hex, base64?), constraints, or how 'memo' and 'credits' affect behavior. This leaves agents guessing about parameter usage.

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 clearly states the purpose: 'anchor a SHA-256 digest on-chain with a verifiable proof.' It uses a specific verb ('anchor') and resource ('SHA-256 digest on-chain'). However, it does not differentiate itself from sibling tools like animica_chain_block or animica_chain_head, which also involve on-chain operations, missing an opportunity to clarify scope.

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 implies usage for notarizing a SHA-256 digest with a verifiable proof, and the 'PAID' marker warns about cost. However, it does not specify when to use this versus alternatives (e.g., other notarization or on-chain tools), nor does it mention any prerequisites or exclusions. The context is clear but lacks explicit guidance.

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