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

The annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, and the description's "opens nothing by itself" is consistent with that, adding useful confirmation that no state changes occur. The API-availability note (no official Planfy API, no Zapier app) explains why the tool is a guide, which is genuine added context. However, it says nothing about auth requirements or whether the returned steps depend on the account state, so with annotations doing most of the work a 3 is appropriate.

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 key facts are front-loaded: what it returns, that it acts on nothing, and which tools to use afterwards. The closing sentence about the API being in development and the dated check (9 Nov 2026) is lengthy justification that could be trimmed, but it is relevant to why the tool exists in guide form.

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?

The description covers the return shape (screens, buttons, fields) and the follow-up path, which is the core need for a no-output-schema tool. The notable gap is that with zero parameters it never explains how the specific appointment is selected, nor what prerequisites exist, leaving an agent to guess about target identification.

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 are no parameter semantics for the description to explain; the baseline for a 0-param tool applies. The description does not address how the target appointment is identified (presumably from conversation context), but that is not a schema-parameter gap.

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 (reschedule an appointment in the user's Planfy account) and immediately clarifies the non-obvious twist: it returns step-by-step instructions rather than performing the action. It doesn't explicitly contrast with planfy_book_appointment or planfy_list_appointments, so the agent must infer that rescheduling is distinct from booking.

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 states the workflow explicitly: call this to get the screens/buttons/fields, then execute with the cotlet_browser_* tools in the Planfy Cloud Browser. That is clear when-to-use guidance. There is no when-not guidance or stated prerequisite (e.g. user must be signed in to Planfy), 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.