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

Annotations already declare readOnlyHint and openWorldHint; the description goes well beyond them by enumerating every failure reason (bad_shape, unknown_block, not_ours, altered, unavailable, self_check_failed) and stating retry semantics for 'unavailable'. 'Read-only' merely repeats the annotation, but the failure-mode disclosure is genuinely useful.

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 core action in the first sentence, then systematically lays out the answer shape and reason codes. It is dense but every clause (especially each reason value) carries information; minor redundancy with the annotation's 'Read-only' clause.

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?

Despite no output schema, the description fully specifies the return object (verified, reason, id), every possible reason value with meaning, and the no-input self-check behavior. An agent has everything needed to invoke and interpret it correctly.

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% and the single receipt parameter's format, unwrapping behavior, and optionality are already fully documented in the schema description. The description adds the provenance ('from any code_* answer') but largely mirrors what the schema provides, so baseline 3 applies.

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+resource: verify a receipt from any code_* answer, and specifies exactly what it determines (issued by this service, unchanged). An agent can distinguish it from code_* and source_verify_bearing siblings without opening the schema.

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?

Clearly says to pass a receipt from any code_* answer, and explains the alternative no-input mode ('With no input, runs the code tools' self-check'). No explicit when-not guidance or named competing tool, but the usage context is unambiguous.

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