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

Annotations include readOnlyHint=false, destructiveHint=true, and openWorldHint=true. The description adds non-contradictory context: it clarifies that the tool performs no external research or outbound actions (fleshing out openWorldHint) and discloses the paid nature and explicit wallet authorization requirement. It also notes the output is a draft for human review. It does not mention destructive side effects, but the annotation already signals that; the description adds value beyond annotations.

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 sentences, front-loaded with the core purpose, and every sentence adds information (output, constraints, payment). No filler or redundancy. It is appropriately concise for the complexity it conveys.

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 has 5 parameters, nested objects, no output schema, and 0% schema coverage. The description does not explain the purpose of result_expires, idempotency_key, result_signature, or payment_signature, nor does it describe the expected return format beyond 'draft for human review'. Given the complexity, the description leaves significant gaps that an agent would need to resolve before calling the tool correctly.

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 0%, so the description must explain parameters. It mentions 'brand brief' and 'payment requires explicit wallet authorization', which partially maps to the 'brief' field and 'payment_signature' parameter, but it does not explain 'result_expires', 'idempotency_key', 'result_signature', or the nested 'input' object's fields beyond the brief. The description is insufficient to guide correct parameter usage for a 5-parameter schema.

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 the specific verb 'Create' and the resource: 'voice principles, vocabulary guidance, examples, and editing rules'. It also specifies the source ('supplied brand brief') and the output ('draft for human review'), making it distinct from sibling copy tools that target different deliverables like ad copy or blog drafts.

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 description provides clear context on when to use this tool: when a brand brief is supplied and the user wants voice principles. It also states constraints: 'Uses buyer-supplied information only; no external research or outbound actions.' However, it does not explicitly name alternatives or state when not to use it, so it stops short of a full 5.

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