AEAT MCP Server

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

With no annotations provided, the description carries full burden. It discloses the tool's behavior as a read-only operation ('Returns') and specifies the data source (Ley 35/2006), but doesn't mention potential limitations like rate limits, authentication needs, or error conditions. It adequately describes what the tool does without contradictions.

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?

The description is efficiently structured in two sentences: the first states the purpose and scope, the second adds context about tax reduction and legal source. Every phrase contributes meaning without redundancy, making it appropriately concise and 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?

Given the tool's low complexity (1 parameter, no output schema, no annotations), the description is reasonably complete. It explains what the tool returns and its tax relevance, though it could benefit from mentioning output format or example usage. The absence of an output schema means the description doesn't need to cover return values in detail.

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 fully documents the single parameter 'year'. The description doesn't add any parameter-specific information beyond what's in the schema, maintaining the baseline score of 3 for adequate coverage without extra value.

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?

The description clearly states the tool's purpose with specific verbs ('Returns') and resources ('personal and family tax-free minimums for Spanish IRPF'), including detailed scope ('taxpayer minimum, descendants, ascendants, and disability allowances'). It distinguishes from sibling tools by focusing on minimums rather than deductions, brackets, or other tax elements.

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 implies usage context by mentioning 'reduce the taxable base' and citing legal sources, suggesting it's for tax calculation scenarios. However, it lacks explicit guidance on when to use this tool versus alternatives like get_irpf_brackets or get_ccaa_deductions, and doesn't specify prerequisites or exclusions.

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