beel_get_default_series

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

Annotations already cover readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the bar is lower — and the description builds on that rather than repeating it. It adds genuine behavioral value: the automatic-flow skip semantics with the specific failure code, the note that 'the environment is resolved from the request context and takes no input,' and a pointer to fiscal guardrails about numbering being non-rewritable. The only slight mismatch is that the 'numbering can never be rewritten' warning is tangential for a read-only tool, but it is still domain-relevant. No contradiction with annotations.

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 purpose is front-loaded in the first sentence, followed by a compact, scannable structure: behavior note, endpoint line, guardrails warning, and docs routing. Every sentence earns its place and the guardrails warning is information-dense. It is mildly verbose for a one-parameter read-only tool — the endpoint duplication and the warning block could be tighter — but the organization makes it efficient to parse.

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, read-only, annotation-rich tool with no output schema and no nested objects, this definition is highly complete: it states what is reported per document type, the domain consequence of missing defaults, the exact endpoint, and where to find exhaustive rules. The only minor gap is not hinting at the return shape or whether results paginate — but the description's 'reports... which one' already sketches the per-document-type structure, so nothing an agent needs to call it correctly is missing.

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%, and the company_id schema description is exceptionally rich — it states the NIF is the only source of context, that BeeL-Active-Company plays no part, and details the 403 behavior and non-disclosure guarantee. The tool description adds minimal parameter meaning beyond restating 'NIF'; its only contribution is confirming that 'no input' other than the schema parameter is needed, which the schema's 'only source of context' phrasing already implies. A solid baseline-3 case where the schema carries the full burden.

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 opening sentence uses a specific verb ('Reports') against a precise resource ('for each DocumentType... whether the company (NIF) has a default invoice series and which one'). It scopes itself to automatic invoicing flows, which separates it from siblings like beel_get_series and beel_list_series. The behavioral consequence (no-default types cannot be issued without an explicit series_id and are skipped with failure.payment.skip.missing_default_series) sharpens the purpose even further.

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 conveys the operational context well — it explains when the result matters (automatic flows skip types with no default) and routes to beel_docs_search for exhaustive rules. However, it never explicitly contrasts itself with the natural mutating counterparts beel_set_default_series and beel_ensure_default_series, nor states when one should be preferred over this read-only check. Usage guidance is implied through context rather than stated as exclusions.

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