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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true and openWorldHint=false, so the safety profile is covered. The description adds one genuinely valuable fact beyond that: the tool returns instructions rather than data and performs no actions itself. Beyond this, it says nothing about the shape of the returned guidance or whether it is static text or account-specific.

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 behavioral clarification is front-loaded, which is good, but the trailing paragraph about Planfy's official API being in development, the JavaScript widget library, and the absence of a Zapier app (with a checked date) is a large amount of justification text for a zero-parameter tool. It supports the 'why a guide' rationale but could be compressed to a clause.

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, non-destructive helper with no output schema, the description covers what matters: that it returns procedural guidance and that execution happens through the browser tools. The only residual gap is the exact form of the returned guidance, which the absence of an output schema makes slightly more relevant.

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 no parameter meaning to convey and the baseline of 4 applies. The description appropriately does not waste space on argument semantics.

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 resource (free slots in the user's own Planfy account) and, importantly, clarifies that the tool does not actually retrieve slot data but instead returns step-by-step instructions for doing it in Planfy. That distinction is stated explicitly ("opens nothing by itself"), which rescues an otherwise misleading name. It stops short of naming which sibling handles the actual booking or listing.

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 does route the agent forward by saying to perform the task with the cotlet_browser_* tools in the user's Planfy Cloud Browser, which is genuinely useful sequencing guidance. However, it never states when to choose this over planfy_book_appointment or planfy_list_appointments, and no preconditions (e.g., browser session required) are given.

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