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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true and openWorldHint=false, so safety is covered. The description adds genuinely non-redundant behavior: the tool only returns procedural instructions and performs no action, and a browser session is required to complete the merge. It does not describe the shape or length of the returned steps or any rate/usage limits, which keeps 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 critical clarification — that nothing is opened and the actual work happens through browser tools — is front-loaded within the first two sentences. The final sentence about Mautic's REST API and lack of an official MCP server is somewhat tangential but justifies the browser-based workflow; the middle sentence is clunky with its semicolon splice.

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, no output schema and strong annotations, the definition covers what an agent needs: what the call returns, that it is non-executing, and which tools complete the task. A brief note on what the returned steps look like or any dependency on an open Cloud Browser session would make it fully complete.

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 input schema has zero parameters, so there is no parameter meaning to add; the baseline for a no-parameter tool applies. The description correctly implies no inputs are needed, since it returns generic step-by-step guidance for the account.

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 resource (merging contacts in the user's Mautic account) and, critically, clarifies that the tool 'Returns how to do it in Mautic step by step (screens, buttons, fields)' rather than performing the merge itself — resolving the tension with the action-oriented name. It does not explicitly differentiate itself from other mautic_* siblings, but it does route to the cotlet_browser_* tools that perform the actual work.

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 sequencing guidance: call this to get the steps, 'then do it with the cotlet_browser_* tools in the user's Mautic Cloud Browser.' It also implicitly excludes execution by saying it 'opens nothing by itself.' What's missing is any statement of when this tool is unnecessary (e.g., if a direct API path exists) or prerequisites such as an authenticated Mautic session.

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