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

Annotations already carry the safety profile (readOnlyHint, idempotentHint), and the description does not contradict them — 'generate... returns' reads as a pure transformation with no persisted side effects. The description adds the return structure (summary plus embedded base64 PDF or XML text), which tells the agent what to expect. It doesn't cover failure behavior or internal validation, but the 'check' parameter's schema partially discloses that.

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 sentences with zero filler, purpose front-loaded ahead of the return-value note. The description is clean but arguably terse for a compliance-critical generator; it shifts most explanatory burden onto the very large schema.

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 essentials are present — what it does, what it returns, and (via annotations) its read-only, idempotent nature — backed by an unusually rich schema. However, with no output schema, the description omits useful context such as validation/failure semantics on non-compliant input, how profiles affect output, and the distinction between the three output formats beyond their names.

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 83%, above the 80% threshold, so the baseline of 3 applies even though the top-level description adds no parameter detail. The schema itself documents output formats, profiles, check rule sets, language, and the extensive Invoice definition with BT codes. Nothing in the description is needed to disambiguate the parameters.

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 a specific verb and resource — 'generate a compliant e-invoice from structured data' — and the title names the standard (Factur-X invoice). Mentioning the return shape (summary plus embedded document) further clarifies what the tool produces. It doesn't explicitly contrast with siblings, but 'generate' versus 'embed/extract/validate' is strongly self-differentiating from the name alone.

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?

No when-to-use or when-not-to-use guidance is given, and no sibling tool is named as an alternative. Usage must be inferred from the verb 'generate' — call this when you have structured invoice data and want a document — with no exclusions, prerequisites, or routing hints.

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