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

Annotations declare it is a non-read-only, non-destructive, open-world write with only that safety profile. The description adds substantial context beyond that: SAT stamping makes the invoice final (no draft), it consumes one folio of the plan, it does not send email, it reaches other people, and it needs a Cotlet API key with app access. This is rich mutation-specific disclosure.

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?

Purpose is front-loaded and every sentence carries information, but the confirmation guidance is slightly redundant ('By default you confirm each call... confirm with the user before each call'), and the run of short clauses reads like a list. Still efficient overall.

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 mutation tool with no output schema, the description states the return values (invoice_id, series, folio, UUID, totals) and covers finality, folio consumption, email behavior, remediation paths, and auth needs. An agent has everything required to call it correctly and safely.

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 the schema already documents all five parameters, including the items line structure. The description only implies 'one or more lines' and adds no syntax or format detail beyond the schema, so the baseline 3 is appropriate.

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 (issue/stamp) and resource (CFDI 4.0 ingreso invoice) and explicitly distinguishes it from the draft-based alternatives by noting there is no draft and the invoice is final on success. It also names sibling tools (email_invoice, cancel_invoice, create_credit_note), so an agent can route without opening schemas.

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 when-to-use-alternative guidance: 'does not email the invoice: use email_invoice for that' and 'A wrong invoice is fixed by cancel_invoice or create_credit_note.' It also gives confirmation prerequisites ('confirm with the user before each call'), leaving little to inference.

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