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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds nothing beyond that; 'safe invoice summary' is undefined and could be read as a behavioral claim, but it is never explained.

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?

A single short sentence with the verb front-loaded and no padding. It is efficient, though the trailing 'safe invoice summary' clause is unexplained enough to be slightly wasteful.

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 read-only single-parameter lookup with no output schema, the description partially covers the return ('credit note and safe invoice summary') but leaves 'safe' undefined. An agent can call it correctly, but the meaning of what comes back is only vaguely conveyed.

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% with a single required 'id' parameter fully documented in the schema, so the description does not need to compensate. It adds no extra meaning about the ID format or constraints, so the baseline of 3 applies.

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 (Get) and resource (credit note), which is clear on its own, but the appended 'and safe invoice summary' is ambiguous jargon that never gets explained. Nothing in the description distinguishes it from siblings like create-credit-note or submit-credit-note beyond the verb.

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?

There is no indication of when to call this tool versus create-credit-note, submit-credit-note, or get-document. No prerequisites, no context about what a 'safe' summary means or when it is appropriate.

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