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

With no annotations, the description carries the full behavioral burden flags. It discloses the pay-per-call cost, settlement network, protocol, and the exact failure mode when the payment-signature header is missing. It also states the tonal constraint that output stays close to the source.

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?

Every sentence earns its place: deliverable, tone, usage routing, and payment behavior. The key output and trigger condition are front-loaded before financial details.

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?

Despite having no output schema, the description enumerates the expected output components clearly. It covers what input to provide, when to use it, what it returns, and what payment prerequisites exist, so an agent has nearly everything needed to invoke it 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 100%, so the baseline of 3 applies. The description reinforces that the query is existing marketing copy and that context is optional, but it does not add substantially new parameter syntax or formatting details beyond the 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 states a very specific deliverable: 3 A/B test variants of existing marketing copy with one variable changed per variant, each with a hypothesis, plus a test plan covering metric, sample size, and duration. It also names scoring-oriented siblings so the agent can distinguish variation from evaluation.

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 explicitly says 'Use when you already have copy to test', giving a clear trigger condition. It also names alternatives with the precise condition 'To score copy without variants, use score-landing-page or predict-viral-potential.'

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