document_validate

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

With no annotations, the description does useful work by declaring the operation stateless, non-pricing and non-rendering, which implies no side effects and no persisted artifacts. But it never says what a failed check produces — an error list, a boolean, an exception — and there is no output schema to fall back on. For a validation tool, the failure behavior is the behavior that matters most.

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, purpose first, then cost/contrast, then routing to alternatives — a sensible front-loaded order. Mild redundancy between 'without pricing it' and 'no totals are computed' costs it a point.

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?

The tool takes a large nested invoice document, and 'well-formed' is left undefined: schema shape only, or EN 16931 business rules too? The sibling compliance_check makes that ambiguity consequential. Combined with no output schema and no statement of what a failure looks like, an agent cannot predict the result of calling it.

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?

The description says nothing about either top-level parameter, and reported schema description coverage for them is 0%, so it fails to compensate on the surface. In practice the nested $defs carry very rich per-field documentation, so an agent can still construct a payload. The description adds no meaning of its own here.

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 object: 'Check that a document body is well-formed', plus the key negative — no pricing. It distinguishes itself from the two neighboring stateless operations. The only blemish is that the named siblings are inverted ('calculate_document'/'render_document' vs. the actual 'document_calculate'/'document_render'), which slightly blunts the differentiation.

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: use the calculate tool for money, the render tool for the document, this one for neither. That is real when-to-use guidance with named alternatives. It does not address the overlap with compliance_check, which is the less obvious boundary an agent would need.

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