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

The annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds useful context — it returns screens, buttons and fields, and performs no side effects itself — but stops short of saying what the response looks like or what happens if no browser session is active.

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 purpose and the no-side-effects constraint are front-loaded and unambiguous. The trailing sentence about Mailshake's REST API and the absence of an official MCP server is background trivia that does not help an agent decide to call or how to call this 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?

For a zero-parameter, read-only guide tool with no output schema the core is present, and the annotations carry the safety information. The significant gap is that with no inputs the description never explains how the agent supplies which leads and which destination campaign — presumably by gathering them in the browser first — leaving the call sequence underspecified.

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?

Zero parameters, so the baseline is 4. The description correctly implies the tool takes no target campaign or lead identifiers, though it does not explain how the agent is supposed to convey which leads and campaign are meant.

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 concrete verb and resource (move leads between campaigns in the user's Mailshake account) and immediately corrects the naming trap by clarifying it only returns step-by-step instructions and 'opens nothing by itself'. That distinguishes it from the other mailshake_* siblings, which act on data. It loses a point only because the headline reads as an action tool while the actual function is guidance.

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 points to the required follow-up ('then do it with the cotlet_browser_* tools in the user's Mailshake Cloud Browser'), which is genuine usage guidance. However it never says when to choose this over a mailshake_* sibling or over the mentioned REST API, and gives no prerequisites (e.g., browser connection, account already open).

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