Get quota

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

Annotations already declare the read-only, idempotent, non-destructive profile, yet the description adds substantial non-obvious behavior: it does not consume a check, it is always free with no x402 charge, and it enumerates the full identity/rate-limit matrix (anonymous IP 100/day, pc_live_ key 1,000/day, bundle header variants). That is real behavioral disclosure beyond the structured fields.

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-loaded with the core purpose, then usage, then exclusions, then identity tiers, then return shape. The identity paragraph is dense but each clause carries distinct operational information (which credential maps to which limit), so little is wasted; only slight tightening is possible.

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?

There is no output schema, and the description compensates by listing the returned fields (subject_kind, limit, used, remaining, resets_at, billed, policy_version). Combined with the usage triggers, exclusions, and quota semantics, an agent has everything needed to call and interpret this tool.

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%, so the baseline is 3, but the description goes further by explaining how identity is resolved (matching check_merchant, and that the key may be supplied via the api_key argument, Authorization: Bearer, or X-API-Key) and what the tiers yield. It clarifies the consequences of omitting api_key (anonymous allowance) rather than just restating the field.

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?

Specific verb and resource: reads the caller's remaining free PayCheck merchant checks for the current UTC day. It explicitly distinguishes itself from the sibling check_merchant by stating it 'does not score a payee' and 'accepts no target', so an agent can route correctly without opening either 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?

Gives explicit trigger conditions ('before a batch of check_merchant calls, or after an HTTP 402') and an explicit exclusion ('Do not use this to score a payee'), plus a cost rule ('Do not pay x402 for this tool. It is always free.'). This is textbook when/when-not guidance.

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