beel_get_fiscal_summary

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive. The description adds valuable behavioral details: period default, max range, error response format (400 with reason in details.reason), and the inclusion of annual projection and bracket breakdown in the output. It also mentions the endpoint. It does not fully describe output structure or potential edge cases, but it goes beyond annotations meaningfully.

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?

Two concise sentences. The first describes the output, the second details constraints and error behavior. No redundant information, fully front-loaded, every sentence earns its place.

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 read-only nature (annotations cover safety), the schema covers parameters, and the description covers output contents and error handling, the definition is quite complete. It lacks an explicit output schema but provides a high-level summary of what is returned. It could mention whether authentication or permissions are needed, but that is likely covered by the endpoint context. Overall, adequate for an agent to call correctly.

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%, so each parameter is already documented. The description adds additional semantic value: the period defaults to the current month, ranges over 365 days are rejected, and inverted ranges trigger a 400. These are constraints not present in the schema, so the description enhances parameter understanding.

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 states exactly what the tool returns: 'Returns the VAT and IRPF summary of the invoices issued under this company (NIF) over the requested period, together with the annual IRPF projection and its progressive bracket breakdown.' This is a specific verb+resource, and it clearly distinguishes from any sibling by naming the fiscal summary concept. No ambiguity.

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 provides clear context: the period defaults to the current month, cannot exceed 365 days, and invalid ranges return a 400 with reason in details.reason. It also notes the endpoint. It does not explicitly name alternatives, but given the unique purpose and the large sibling list, the usage context is sufficiently clear. It could improve by stating 'use this when you need fiscal summary data' but it's adequately implied.

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