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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and the description is consistent with them ('opens nothing by itself'). Beyond that it discloses the return content (step-by-step screens, buttons, fields) and pre-empts the obvious 'why not the API?' question by noting Mailshake has a REST API but no official MCP server, which explains why browser automation is required. It stops short of describing output format or failure modes.

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 constraint ('opens nothing by itself') is front-loaded in the first sentence, ahead of the follow-up instruction, which is good ordering. Some wording is filler — 'from ChatGPT, Claude or any AI agent' adds nothing for tool selection — and the trailing API footnote is long, though it does answer a real question.

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, no-output-schema tool with rich annotations, the description covers what it returns, what it does not do, and what the caller must do next. The only gap is how the guidance identifies which campaign to operate on, given there are no inputs, but that is a minor ambiguity for a guidance-only tool.

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, so there is nothing for the description to disambiguate; baseline 4 applies. The absence of parameters is implicitly explained by the fact that the tool only returns guidance rather than operating on a specific campaign.

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 name/title suggest a mutation, but the description explicitly corrects this: the tool 'Returns how to do it in Mailshake step by step (screens, buttons, fields) and opens nothing by itself.' That is a specific and unusual purpose (an instruction provider, not an actor) stated clearly enough that an agent can tell it apart from the cotlet_browser_* tools that actually perform the work. The only weakness is that the leading sentence 'Add recipients to a campaign...' reads as the action itself before the clarification lands.

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 an explicit two-step workflow: call this to get the steps, 'then do it with the cotlet_browser_* tools in the user's Mailshake Cloud Browser.' That is clear when-to-use and what-to-do-next guidance. It does not say when NOT to use it or contrast it with the similarly named Mailshake siblings (move_leads, add_a_follow_up), which keeps it below a 5.

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