Retrieve (verify) a payment by your reference

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only the 'verify' framing, saying nothing about what happens when no payment matches the reference or whether the call errors versus returns empty — the main behavioral gap an agent would care about.

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?

Two short sentences with the lookup key front-loaded, but the opening restates the tool title near-verbatim and then repeats 'Retrieve a payment by the reference' again in the next sentence. Tightening to a single sentence would lose nothing.

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 two-parameter read-only lookup with no output schema, the description leaves the return value and the not-found behavior undescribed; an agent cannot tell whether a miss raises an error or returns null. What is present is accurate but thinner than the tool's surface warrants.

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 description coverage is 100%, so both `reference` and `expand` are documented in the schema itself. The description repeats that the reference is one 'you gave it' but adds no format, length, or uniqueness constraints, and never mentions `expand` — which is acceptable under full schema coverage, hence the baseline 3.

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 names a specific verb and resource (retrieve a payment) plus the lookup key (your `reference`), and the second sentence implicitly contrasts with the by-id sibling by noting you may have stored an order id but not the Pletopay payment id. It never names `get_payment` explicitly, so the differentiation must be inferred from the sibling list rather than read directly.

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 clause 'useful when you stored your order id but not the Pletopay payment id' gives a concrete situation that selects this tool over the by-id alternative. It stops short of an explicit 'do not use when you have the payment id' instruction, so the routing cue is clear but not fully spelled out.

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