Registrar factura recibida

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

With only readOnlyHint=false supplied, the description adds real behavioral context: the server computes IVA and taxable bases per line, Contasimple rejects duplicates keyed on número+proveedor+año, and write access must be enabled. It does not say what is returned (e.g. the new invoice id) or how the duplicate rejection surfaces (error vs silent skip), which would be needed for a 5.

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?

Three short sentences, each carrying distinct information: what it creates, the server-side tax calculation, the duplicate-rejection constraint, and the write-access prerequisite. Nothing is redundant and the core action is front-loaded.

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 11 parameters, 73% schema coverage and no output schema, the description covers creation behavior and duplicate handling well. However, it never states the return value (invoice id for follow-up tools such as cs_attach_file or cs_add_payment), leaving a meaningful gap for a create operation.

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 73%, so the schema already documents most fields including proveedorId, numero, fecha, claseId and the line-level base/ivaPorcentaje. The description adds meaning by explaining that IVA and bases are computed per line, but it does not clarify the interaction between base, ivaPorcentaje, imputacion or retencionPorcentaje, so 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: 'Registra una factura recibida (de un proveedor)', which clearly distinguishes it from sibling creation tool cs_create_provider and from read tools like cs_list_invoices. It does not explicitly name which sibling handles the alternative path, keeping it below 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?

The description gives a precondition ('Requiere escritura activada') which is genuine usage guidance, but it offers no when-to-use vs alternatives routing, e.g. checking for an existing invoice with cs_search_invoice_by_number before creating, or resolving proveedorId via cs_search_entities. Usage is implied rather than stated.

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