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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with the concrete claim that the tool "opens nothing by itself" — a meaningful behavioral assurance. It also discloses the shape of the return value (step-by-step screens, buttons and fields), which annotations cannot convey. The API pricing tangent adds no behavioral value, keeping it short of a 5.

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 tool's actual behavior and the browser-handoff are front-loaded, which is good. But the third sentence about Fiken's REST API v2, its check date and the 99 NOK/month add-on price is longer than the rest combined and is irrelevant to selecting or invoking this tool — it neither changes behavior nor guides usage.

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 zero parameters, no output schema and full annotation coverage, the definition covers the essentials: what it returns, that it is side-effect free, and what to do next. Gaps remain around prerequisites (e.g., whether the user must already be signed into the Fiken Cloud Browser) and around why an agent would choose this over cotlet_app_guide.

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 (empty object, additionalProperties false), so there is no parameter meaning to add and the baseline of 4 applies. Schema coverage is 100% for the trivial 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 first sentence names a specific verb and resource ("List unpaid invoices"), but the second sentence reveals the tool does not list anything itself — it "Returns how to do it in Fiken step by step." That self-correction is useful, yet the name/behavior mismatch leaves the agent needing to re-read to understand what it actually gets back, and the tool is never distinguished from the guide-style sibling cotlet_app_guide.

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 does describe the workflow handoff clearly: this tool produces instructions, then "do it with the cotlet_browser_* tools in the user's Fiken Cloud Browser." That is real usage context. However, there is no when-not guidance and no comparison to other planning/guide tools such as cotlet_app_guide, so the agent must infer which planning tool to pick.

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