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

Annotations already declare readOnlyHint=true, destructiveHint=false and idempotentHint=true, but the description adds genuinely new context: "opens nothing by itself" explains why a balance-adjustment tool is non-destructive, and the two-step handoff to the browser tools is a behavioral trait not encoded anywhere in the structured fields. The paid-API aside is informative but not strictly behavioral.

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 and the browser-handoff instruction are front-loaded and useful, but the trailing sentence quoting Exercise.com's API add-on pricing (with a quote and a check date) is tangential to the tool's operation and consumes roughly a third of the text. Trimming that would sharpen an otherwise tight definition.

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, closed-world guidance tool with no output schema, the definition supplies what an agent needs: what it returns (screens, buttons, fields), what it does not do, and which tools complete the workflow. It omits prerequisites such as whether the user must already have a connected Exercise.com Cloud Browser session, which would have made it fully complete.

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 input schema accepts no parameters, so there is no parameter meaning for the description to add. Baseline for a zero-parameter tool applies.

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 definition gives a clear verb+resource ("Adjust account balance in the user's own Exercise.com account") and, importantly, immediately corrects the natural misreading by stating it "Returns how to do it ... step by step" rather than performing the action. It distinguishes the tool from the execution path by naming the cotlet_browser_* tools. It does not differentiate itself from the many other exercise_com_* guidance siblings, but the purpose is unambiguous.

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?

Usage is implied rather than stated: the agent can infer this is the tool to call when a user wants to change their Exercise.com balance, and the description supplies the sequencing (call this first, then act via cotlet_browser_*). There is no explicit "when not to use" or exclusion, and no mention of the relevant sibling tools for other Exercise.com tasks.

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