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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the description needn't restate that it's destructive. It adds genuine value beyond annotations: it reassures that deletion is safe because gastos are outside the invoice chain, and it discloses the return value (deleted expense's id). Missing only an explicit reversibility/no-undo note.

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, front-loaded with the action, then the key safety distinction, then the id-lookup hint. No padding; each sentence carries distinct information.

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-parameter destructive tool with full schema coverage and annotations covering the safety profile, the description supplies everything needed: how to find the id, why deletion is safe, and what is returned. Nothing an agent needs to call it correctly is absent.

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 single parameter's description already says 'expense id from list_expenses', so the description's 'by id' plus the list_expenses pointer largely echoes the schema. Adequate but no added syntactic or format detail beyond what's structured.

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 ('Delete an expense by id') and then distinguishes it from the invoice-related siblings by clarifying that gastos are plain expense records not in the Verifactu invoice chain. An agent can separate this from delete_invoice/delete_bank_transactions without opening any 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?

Explicitly routes the agent to list_expenses to obtain the id, and clarifies the domain context (gastos are not invoices) that governs when this deletion is appropriate. It stops short of spelling out exclusions such as irreversibility warnings, so it's clear but not fully exhaustive.

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