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

Beyond the readOnlyHint/idempotentHint annotations, it discloses the key behavioral fact that the tool 'opens nothing by itself' and only returns a how-to, plus that real action requires chaining with cotlet_browser_* tools. The partner-only API note explains why browser automation is needed. It is consistent with the read-only annotations and adds real value, though it says nothing about failure cases or what happens if the user is not signed in.

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 is front-loaded and the instruction-only nature is stated early, which is good. But the middle sentence is a long run-on mixing return format, non-action, and tool chaining, and the closing API/partner-access paragraph is tangential detail that dilutes the actionable guidance.

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 guidance tool with no output schema, the description covers what it returns (screens, buttons, fields) and how to act on it. Annotations already carry the safety profile. Only minor gaps remain, such as preconditions (being logged in) or what a guide response looks like if enrollment is unavailable.

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. The description correctly implies no arguments are needed and directs where user-specific context comes from (the user's own account, then the Cloud Browser).

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 names a specific verb and resource (enroll in membership in Zen Planner) and immediately clarifies that the tool returns step-by-step instructions rather than performing the enrollment. That resolves the ambiguity a bare name like 'enroll' would create. It does not explicitly contrast itself with siblings such as zen_planner_book_class, so it stops short of 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 implies usage ('when the user wants to enroll a membership in their own Zen Planner account') and explicitly prescribes the follow-up path: perform the steps with cotlet_browser_* tools in the Cloud Browser. However, it gives no explicit exclusions or comparison to other Zen Planner siblings, so the agent must infer when this tool is the right entry point versus, say, listing members first.

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