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

Beyond the readOnlyHint annotation it discloses the status model (open/paid/expired/review), that the bearer token becomes usable on paid, that tx_hash gets set, confirmation latencies per chain (TRON/Solana ~1 min, Ethereum ~15 min), and a rate-limit instruction. It does restate 'read-only' which the annotation already covers, but the added behavioral context far exceeds that.

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 condition and uses an efficient semicolon-enumerated status list. Slightly dense in a single block and the 'read-only and free' clause duplicates the annotation, but no sentence is genuinely wasteful.

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 single-param polling tool with an output schema present, the description supplies everything an agent needs: precondition, cadence, status interpretation, and next actions per status. Nothing material is missing.

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 schema's own property description already says 'invoice id returned by create_invoice', so the description's instruction to pass the invoice_id from create_invoice adds little new meaning. Baseline 3 applies where the schema does the heavy lifting.

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 and resource ('learn whether the plan is active') scoped to a lifecycle position ('after create_invoice, once the USDT transfer was sent'), which clearly separates it from create_invoice and the other check_* siblings.

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?

Explicitly names when to call it (after create_invoice following the USDT transfer), what to do in each outcome (expired means create a new invoice; review means manual match), and imposes a concrete polling cadence ('poll at most once a minute').

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