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 is consistent with them by stating the tool "opens nothing by itself." Beyond the annotations, it discloses the return shape (step-by-step screens, buttons, fields) and explains why the official Phorest API route is blocked (credentials only via Phorest Support, own development team required). It adds no error or fallback behavior, which keeps 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 most important fact — that this returns instructions and opens nothing — is front-loaded in the first two sentences, which is good structure. The opening clause "from ChatGPT, Claude or any AI agent" is marketing filler, and the trailing API paragraph with the "checked 8 Nov 2026" stamp is somewhat tangential, though it does justify the browser-based route.

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 guidance tool with no output schema, the description carries the necessary burden: it says what is returned and what the agent should do next. Missing is any note on whether the steps are Phorest-version- or region-specific, or what happens if the Cloud Browser session is not already logged in.

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 nothing for the description to disambiguate and the baseline of 4 applies. The description does not incorrectly imply that appointment details are supplied as arguments.

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 makes the actual behavior explicit: it "Returns how to do it in Phorest step by step (screens, buttons, fields) and opens nothing by itself," which corrects the impression from the name that it performs a booking. It names the follow-up tool family (cotlet_browser_*) so the agent knows this is a guidance tool, not a mutator. It does not distinguish itself from the sibling cotlet_app_guide, which could plausibly also return step-by-step app instructions, leaving some ambiguity.

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?

Clear sequencing guidance is given: get the steps here, then execute them "with the cotlet_browser_* tools in the user's Phorest Cloud Browser." That is a usable when-and-how. However, there is no explicit exclusion versus related siblings such as phorest_reschedule_appointment or phorest_find_free_slots, and no statement of prerequisites (e.g., whether the user must already be authenticated in the Cloud Browser).

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