q402_receipt

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

With no annotations provided, the description carries the full burden. It discloses read-only behavior ('Read-only; no API key required'), explains the internal verification process ('re-runs the same canonical-JSON + EIP-191 recovery'), and warns about the unimplemented txHash path. It does not describe error formats or rate limits, but the essential behavioral traits are covered.

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 two sentences plus a parenthetical, front-loaded with the main purpose. Every sentence provides necessary information: purpose, usage context, parameter requirement, and behavioral caveat. No redundant or filler content.

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's simplicity (2 parameters, no output schema), the description fully covers what the agent needs to know: what it does, when to use it, what to pass, and what it returns (settlement record + boolean). It even mentions the future txHash lookup. No significant gaps 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?

Schema coverage is 100% with descriptions for both parameters. The tool description adds crucial value by explicitly stating 'receiptId is required' (despite schema not marking it required) and explaining that txHash is unimplemented and will return notFound. This goes beyond the schema and helps the agent choose the correct parameter.

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 tool's function: 'Look up a Q402 Trust Receipt by its rct_… receiptId and return the settlement record + a locally-verified ECDSA boolean'. It identifies the specific resource (Q402 Trust Receipt) and the action (look up), distinguishing it from sibling tools like q402_pay (which creates) and q402_balance (which queries balances).

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 explicitly states when to use: 'Use after q402_pay to give the user a shareable verified-by-Q402 URL, or to independently verify a receipt id someone shared with you.' It also clearly says that passing only txHash returns notFound, implying receiptId is the correct path. However, it does not name alternative tools for exclusion, though it is contextually clear.

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