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

With no annotations, the description carries the behavioral burden and does well: it discloses content-hash idempotency, relayer-signature validation, and that the counterparty never contacts Robyn. It could add more about failure modes or return behavior, but it provides substantial behavior beyond the 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?

The description is concise and front-loaded with the core action. Each sentence adds useful information about provenance, idempotency, and signature constraints, though the first sentence is somewhat dense with the parenthetical proof explanation.

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 3-parameter tool with no output schema or annotations, the description provides enough context about purpose, prerequisites, validation, and retry behavior. It does not explicitly state the return value, but the surrounding context and idempotency note make the tool sufficiently complete for correct invocation.

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?

The schema already documents all parameters with 100% coverage, establishing a baseline of 3. The description adds meaningful semantics by clarifying that the 'receipt' comes from robyn_settle or a completed route, is relayer-signed, and must be accepted by this relayer, elevating the score.

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 a specific action: delivering a relayer-signed settlement receipt to the counterparty's sealed messaging-v2 mailbox. It distinguishes this from related tools like robyn_settle and robyn_receipt_verify by emphasizing delivery to the counterparty and the acceptance of only relayer-signed receipts.

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 gives clear contextual guidance by tying usage to 'robyn_settle / a completed route' and notes that the receipt provides proof without contacting Robyn. It stops short of explicitly naming alternative tools or stating when not to use this tool, so it slightly misses the top bar for usage guidance.

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