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

The description states 'Writes nothing,' which contradicts the annotation readOnlyHint=false. Since readOnlyHint=false tells the agent this tool may modify state, the description directly conflicts with structured metadata, so this is an annotation contradiction.

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 three tight sentences: the purpose is front-loaded, followed by the safety behavior for drafts and the free-tier footer limitation. Every sentence adds useful information with no filler.

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 low-complexity two-parameter tool, the description covers formats, draft rendering behavior, side effects, and free-tier limitations. It does not specify the exact return payload or error cases, but these are not required by an output schema and the usage intent is clear.

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%, so the schema already fully documents both parameters. The description adds only format-choice context and does not contribute new parameter semantics beyond what the schema 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 a specific action (render), a resource (credit note), and the two output formats (Markdown and printable HTML). It distinguishes this tool from CRUD siblings like credit_note_get and credit_note_list by focusing on document generation rather than data retrieval.

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?

It provides concrete use context: Markdown for pasting into emails/tickets and HTML for a self-contained printable page. However, it does not explicitly guide the agent toward alternatives for raw credit-note data, so it stops short of a 5.

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