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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description corroborates this clearly with 'opens nothing by itself' — important because the name sounds like a mutation. It also discloses the shape of the return value (screens, buttons, fields), which annotations cannot convey. The note about ClickSend's official REST API and narrow MCP server is extra context but does not add behavioral guidance the agent needs.

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 information is front-loaded and the 'opens nothing by itself' clarification is well placed. However, the closing sentence about ClickSend's official REST API and MCP server being 'narrow (checked 23 Oct 2026)' is tangential, dated, and does not help an agent decide or call the tool, which dilutes an otherwise tight definition.

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?

There is no output schema, so the description must explain the return value, and it does — a step-by-step procedure covering screens, buttons, and fields — plus the explicit handoff to cotlet_browser_* tools. For a zero-parameter guide tool with annotations covering the safety profile, that is nearly everything an agent needs.

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 fully specified, so there is no parameter meaning for the description to add. Baseline 4 applies; no misleading parameter claims are made.

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 the specific task (removing opted-out contacts in the user's ClickSend account) and, crucially, clarifies what the tool actually produces: 'Returns how to do it in ClickSend step by step (screens, buttons, fields) and opens nothing by itself.' That separates it from the cotlet_browser_* tools that perform the action. It does not explicitly distinguish itself from near siblings like clicksend_remove_duplicate_contacts or clicksend_add_to_opt_out_list, which keeps it from a 5.

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?

The workflow is spelled out: call this first to get the step-by-step procedure, 'then do it with the cotlet_browser_* tools in the user's ClickSend Cloud Browser.' That is clear guidance on when to use this tool versus the browser automation tools. It lacks an explicit when-not or a direct comparison against the similarly named opt-out/duplicate removal siblings.

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