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 safety profile is covered. The description adds genuinely non-redundant behavior: the tool returns procedural instructions covering screens, buttons and fields, and performs no action itself. That 'opens nothing by itself' statement is the key expectation-setting detail. It stops short of describing how much guidance is returned per call or whether the steps depend on the user's current Fillout page.

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 operational content is front-loaded and clear in the first two sentences. The closing paragraph about Fillout's REST API is lengthy and mostly defensive background; only the clause 'it cannot create or edit forms' does real work in justifying the browser route. The section reads as justification for the tool's existence rather than information needed to call it.

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 zero-parameter, read-only guidance tool this covers the essentials: what it returns, that it mutates nothing, and which tools carry out the action. Because there is no output schema, the description carries the full burden of describing the response, and 'screens, buttons, fields' is only a partial sketch of the return shape. The unresolved question of how the target form is identified is the main completeness gap.

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?

With zero parameters there is no schema-level meaning to compensate for, so the baseline of 4 applies. The description adds no parameter discussion because there is nothing to disambiguate. A brief note that the target form is inferred from the user's Fillout Cloud Browser session would have closed the only real semantic gap.

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 specific verb and resource ('Close form in the user's own Fillout account') and clarifies the operating mode: it returns step-by-step instructions and 'opens nothing by itself', rather than performing the close. That distinction is the most valuable part of the definition. What remains unresolved is what 'close' means in Fillout terms (unpublish, disable submissions, or close the builder view), so the agent still cannot tell precisely which end state it is being told how to reach.

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 routing: use this to get instructions, then execute with the cotlet_browser_* tools in the user's Fillout Cloud Browser. The API paragraph implicitly explains when the API route is unavailable ('cannot create or edit forms'), which justifies the browser path. It stops short of explicit when-not guidance (e.g., what to do if the user is not already in a browser session, or how it differs from fillout_publish_form).

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