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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, idempotentHint=true, openWorldHint=false), so the bar is lower, and the description still adds real value: it discloses that the tool performs no action itself and returns a step-by-step guide with screens, buttons and fields. The note that Findymail has a REST API but no first-party MCP server explains why browser automation is required, though the dated "checked 23 Oct 2026" stamp and the absence of any return-format detail keep 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?

Only three sentences, so there is little bloat, but the structure is poorly front-loaded: the single most decision-relevant fact — that this returns instructions rather than data — sits in the middle of sentence two, behind a lead that misdescribes the tool. The trailing API-availability aside is contextual but not needed to invoke the tool correctly.

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 description does the remaining work: it states what is returned (step-by-step screens, buttons, fields), that nothing is opened, and which sibling family to use next. It is close to complete for this complexity, missing only guidance on prerequisites such as having a Findymail Cloud Browser session available.

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 and the schema is an empty closed object, so there is nothing for the description to disambiguate. Baseline of 4 applies; the description correctly implies no inputs are needed.

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 opening sentence claims a verb+resource ("List contact lists in the user's own Findymail account"), but the second sentence reveals the tool does not list anything — it "Returns how to do it in Findymail step by step" and "opens nothing by itself." The real purpose (emit a how-to guide that the agent then executes via cotlet_browser_* tools) is only inferable after reading past the misleading lead, so the purpose is stated but internally conflicted.

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 a follow-on instruction ("then do it with the cotlet_browser_* tools in the user's Findymail Cloud Browser"), which implies the workflow. However, it never says when to prefer this over the near-identical sibling cotlet_app_guide, nor what to do if a cloud browser session is not open, leaving the selection decision partly to inference.

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