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

With no annotations, the description must carry the full burden of behavioral disclosure. It lists what the tool does (validations) but does not disclose side effects, permissions, rate limits, or potential failures. No indication of whether it is read-only or modifies any state.

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 a single, well-structured sentence that front-loads the core value proposition ('Complete invoice analysis in one call') and lists key features compactly. No fluff or redundant information.

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 is complex (multiple validations) and has no output schema, so the description should provide more context about return structure and when to choose this over siblings. It covers the main features but is missing usage trade-offs and response format details.

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?

Both parameters (pdf_path, pdf_base64) are documented in the schema with 100% coverage, so the baseline is 3. The description adds no additional meaning about parameter usage or format beyond what the schema already provides.

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 it performs 'complete invoice analysis in one call' and enumerates specific components (extracted fields, line items, ZUGFeRD check, §14 UStG validation). This distinguishes it from focused siblings like invoice_extract or invoice_validate.

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 phrase 'in one call' implies a use case for comprehensive analysis, but there is no explicit guidance on when to use this instead of individual sibling tools, nor any exclusions. It does not mention alternatives, so it is minimally useful for decision-making.

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