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

Annotations already declare readOnly, idempotent, non-destructive and openWorld=false, so the safety profile is covered. The description usefully adds that the tool has no side effects ('opens nothing by itself') and that the return is a sequence of screens/buttons/fields, but it says nothing about response format, freshness of the guide, or limits on account scope.

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 core message is front-loaded, but the sentence packing 'Returns how to do it in Studio Ninja step by step (screens, buttons, fields) and opens nothing by itself' is dense and slightly repetitive. The closing paragraph about no public API, webhooks or Zapier app is informative context but verbose for a zero-parameter tool.

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 parameters and no output schema, the description carries the burden of explaining what comes back, and it does: a step-by-step procedure and a pointer to the cotlet_browser_* tools for execution. The API-availability note explains why browser automation is required, though it could more directly state that no overdue-payment data is returned by this call.

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 there is nothing for the description to disambiguate and the baseline of 4 applies. The description confirms the implicit scope (the user's own account) without implying any hidden inputs.

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 verb and resource ('List overdue payments') and scopes it to 'the user's own Studio Ninja account', then corrects a likely misreading by stating it returns step-by-step instructions rather than the data itself. It does not explicitly separate itself from siblings like studio_ninja_send_invoice or cotlet_app_guide, so it stops short of a 5.

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 gives clear workflow routing: call this first for the procedure, then execute it with cotlet_browser_* tools, and it states it 'opens nothing by itself'. It offers no explicit when-not-to-use case or named alternative (e.g. cotlet_app_guide), which keeps it below a 5.

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