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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false; the description reinforces this with the explicit statement that it 'opens nothing by itself', so there is no contradiction. It further adds behavior the annotations cannot convey: the response is procedural guidance, not data mutation, and the actual change requires a separate browser toolchain.

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 purpose is front-loaded and the total length is modest, but the phrasing is loose: 'CoachingPortal's official API: CoachingPortal publishes no public API' is redundant, and the semicolon-joined clause 'opens nothing by itself; then do it with...' bundles two distinct ideas into one sentence.

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 tool with no output schema, the core loop (get instructions, then act via browser tools) is covered. What is missing is scope: with no parameters, an agent cannot tell which custom exercise or which operation (create vs. update vs. delete) this guidance targets, leaving a meaningful gap for a 'manage' tool.

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 has zero parameters and schema coverage is 100%, so there is nothing to disambiguate. Baseline 4 applies; no parameter-level meaning is missing.

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 concrete resource (custom exercise) and, more importantly, clarifies what the tool actually does: it returns step-by-step CoachingPortal instructions (screens, buttons, fields) rather than performing the action. The verb 'manage' is still broad (create/edit/delete are not distinguished), and no sibling is named for contrast, so it falls short of 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 gives a usable workflow: call this to get guidance, then execute with the cotlet_browser_* tools in the Cloud Browser, and it notes there is no public API. However, it never says when to prefer this over similarly named siblings such as coachingportal_manage_personal_workout, nor does it state any when-not conditions.

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