payment_status

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

Annotations only declare readOnlyHint and idempotentHint=false; the description explains the underlying behavior that makes those true: it reads the chain rather than mutating, the same authorization settles at most once, and the signature must never be passed. That is meaningful context the annotations cannot convey.

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 trigger and the ordering rule, then parameters, then return shape — a logical sequence. The prose is dense with clauses and could be broken into bullets, but no sentence is filler.

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?

Covers trigger, parameter selection, safety warning, and return semantics, which is everything needed for a five-parameter read-only status tool. Enumeration of retry verdicts is partly redundant with the output schema but still aids correct branching.

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 saying which parameter subset applies: tx if available, otherwise from + nonce + valid_before for EVM exact, with network required. It also warns to omit the signature, adding a constraint absent from the schema.

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 concrete verb and resource: it checks settlement state of a paid x402 payment by querying the chain. It also names the return payload (state plus retry verdict), so an agent knows exactly what it gets back.

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 (after a timeout, a 5xx, or any unclear answer) and an explicit ordering constraint (BEFORE signing a new payment). It also routes between two invocation modes (tx-based vs. EVM authorization fields), which is a genuine when-to-use distinction.

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