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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the bar is lower. The description still adds meaningful behavior beyond them: it 'opens nothing by itself', it returns screens/buttons/fields, and it notes the lack of a self-serve API key, which tells the agent why browser automation is needed instead of an API call.

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?

Front-loaded with the core action and the key clarification ('opens nothing by itself') in the first sentence. The trailing sentence about ProSolutions API help is slightly tangential to invoking this tool, but it earns a place by justifying the browser-automation path.

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?

With no input parameters, no output schema, and full annotation coverage, this is a lightweight guidance tool. The description says what comes back (step-by-step screens, buttons, fields) and how to act on it, which is the information an agent needs; only the exact response shape is unspecified.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter semantics to add. The schema is closed with additionalProperties=false and nothing in the description contradicts that.

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?

Names a specific verb and resource ('Apply account payment in the user's own Paired Plus account') and immediately clarifies the actual behavior: it returns step-by-step instructions rather than performing the mutation. This resolves the tension with the imperative name/title, though it never contrasts itself with transaction siblings like paired_plus_charge_card_on_file or paired_plus_checkout_sale.

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?

Implies the usage pattern — call this to get the walkthrough, then execute it with the cotlet_browser_* tools in the Cloud Browser. That is real workflow guidance, but there is no explicit when-not-to-use or statement of which other payment tools are alternatives when the agent wants to actually post a payment programmatically.

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