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

Annotations say readOnlyHint=false with idempotentHint=true, which implies some non-read side effect on repeated-safe calls, yet the description reads like a pure status lookup and never explains that side effect, nor what happens for unknown/unpaid invoices or how fresh the on-chain observation is. The tension between 'check' phrasing and readOnlyHint=false is left unresolved for the agent.

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?

A single front-loaded sentence covering both the paid/not-paid verdict and the on-chain evidence, with no filler. Slightly awkward trailing phrase ('for it') is a minor blemish.

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?

With no output schema, no parameter descriptions, and annotations that only flag non-read-only plus idempotency, the description should explain the shape of the answer (what fields the on-chain transfer evidence contains) and what triggers any write behavior. Neither is present.

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?

One required parameter with 0% schema description coverage: invoice_id is only typed as a uuid, with no statement of which invoice identifier namespace it belongs to or how errors surface for a bad id. The description does not compensate for that gap at all.

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 resource (invoice payment status) and a specific extra payload (on-chain stablecoin transfers seen to the seller's wallet), which distinguishes it from generic invoice getters like get_invoice. It does not name a sibling explicitly, so it stops short of a 5.

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?

There is no statement of when to call this versus get_invoice or get_invoice_passport, no prerequisites (e.g. whether the invoice must be finalized/sent), and no exclusions. Usage is only implied by the tool name.

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