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

Far exceeds the annotations: it decodes the status/settlement_status state machine, warns that status=paid alone does not mean crypto arrived, explains that broadcast/reported/none do not prove failure, and stresses that 'delayed' means the PIX was paid and must not trigger a second charge. It adds auth requirements, rate limits, and destructive-mistake warnings the readOnly/idempotent hints 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-loads the core purpose, then layers in escalation-relevant detail; nearly every sentence carries operational weight (state meanings, sandbox warning, error actions). It is dense and slightly sprawling across three paragraphs, but the length is largely justified by the subtle state machine it describes.

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, the description must carry return-value semantics, and it does so thoroughly — decoding every status/settlement_status value, interpreting delay_until, settlement_proof, settlement_tx_hash/url, and sandbox. Error handling and the 'expired is terminal' path are also covered, leaving nothing an agent needs before calling.

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?

Only one parameter and schema coverage is 100%, with the schema already describing charge_id as the id returned by lunium_create_pix_charge. The description references charge semantics extensively but adds no format or syntax detail beyond the schema, so the baseline 3 applies.

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 — 'Returns the state of a charge created with lunium_create_pix_charge' — and explicitly distinguishes itself from the sibling lunium_verify_pix_payment. An agent can tell exactly what this does and when it does not apply without opening the 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 scope ('only for charges you created'), names the alternative for other PIX (lunium_verify_pix_payment), specifies a polling cadence (10-15 seconds), and maps error codes to actions (back off, retry once, terminal expired). Nothing is left to inference.

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