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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile needs no restating. The description adds genuinely useful non-annotation behavior: output is gated by Pro status, yielding either the full Copy/UX workflow and voice rules or a reduced module overview plus seven rules. It does not say whether the tool establishes state or returns plain guidance text, which matters for a tool named 'start'.

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?

Two sentences, front-loaded with the timing directive, followed by the value proposition split by tier. The long enumeration is dense but each item sharpens the trigger scope; no filler or hedging sentences.

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 one-optional-parameter, no-output-schema tool with safety covered by annotations, the description supplies what an agent needs to decide to call it and what it will receive back at a tier level. Minor gaps remain around return format and follow-up steps such as reviewing or rule-lookup tools, but nothing blocking.

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?

There is a single optional 'task' parameter and schema description coverage is 100%, with the schema itself supplying example values like 'error messages for a payment form'. The description contributes no additional meaning about how task shapes the returned rules, 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?

The description names a specific trigger and enumerates the content types covered (button labels, error messages, empty states, emails, onboarding), and clarifies what is returned with and without Pro (full workflow + voice rules vs. module overview + seven rules). It is clearly a copy/UX-writing entry point rather than the general or review tools in the sibling list, but it never explicitly names a sibling it is not, leaving differentiation partly inferential.

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 'Call this BEFORE writing words people will read in a product' line is an explicit temporal trigger tied to concrete artifacts, which is strong when-to-use guidance. It stops short of exclusions or routing advice (e.g., which tool to use after drafting, or for non-copy work), so it is clear context without alternatives.

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