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

Annotations already declare readOnly, idempotent and non-destructive, but the description adds genuinely useful context beyond them: it returns guidance (screens, buttons, fields) and "opens nothing by itself," so the agent knows a browser call is required to actually act. The note that Planning Center's official MCP is mostly read-only explains the rationale for the browser route. The trailing API/MCP paragraph is background rather than behavior, keeping it from 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 core behavior—returns a how-to, opens nothing, use browser tools next—is front-loaded and tight. The final sentence about Planning Center's REST API and August 2026 MCP server is lengthy background that does not help an agent invoke this tool and dilutes the message.

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 safety fully covered by annotations, the only real burden is explaining what the call yields and what to do next, and the description does both. It slightly undersells what the instruction payload looks like (e.g., whether it includes navigation entry points), which is the only gap.

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 the baseline is 4 and there is no parameter meaning left to convey. The input schema (empty, additionalProperties false) fully describes the contract.

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?

States a specific verb and resource ("List first-time guests in the user's own Planning Center account") and the description immediately clarifies that it returns step-by-step instructions rather than the guest data itself. The name alone would imply data retrieval, but the description corrects that within the first two sentences. No sibling is named, keeping it below 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?

It clearly signals the follow-up path: "then do it with the cotlet_browser_* tools in the user's Planning Center Cloud Browser," which tells an agent what happens next. However, it never says when to choose this over alternatives such as planning_center_search_people or the browser tools directly, and no exclusion conditions are given.

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