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

The description contradicts the annotations: it claims 'no external research or outbound actions' while openWorldHint is trueDM. It also describes a harmless draft output while destructiveHint is true, though it does partially address side effects with payment/wallet authorization. This is a serious behavioral mismatch.

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 compact, front-loaded with the core function, and each sentence adds a distinct piece of information: function, input constraint, output nature, and payment. It could combine the price and authorization statements, but it is still disciplined and readable.

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 description is incomplete for a paid tool with five parameterschers, a nested input object, and no output schema. It does not explain the purpose of the opaque signature/idempotency parameters, what 'draft for human review' means in terms of returned structure, or how the payment flow works beyond wallet authorization. An agent would struggle to invoke this 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%, and the description adds almost no meaning to the parameters. It vaguely refers to 'supplied page facts' but never explains brief, source_text, audience, result_expires, idempotency_key, result_signature, or payment_signature. The description does not compensate for the schema's lack of documentation.

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 ('Generate') and a specific resource ('page titles and descriptions from supplied page facts'), and it adds output details ('character counts and intent notes'). It clearly differentiates from research-heavy services with the explicit constraint that only buyer-supplied information is used.

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 gives no guidance about when to choose this tool over alternatives, and it never names or distinguishes sibling services. The 'no external research' constraint implies an input boundary, but it does not explain when an agent should prefer metadata_rewrite over other content-generation services.

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