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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that by stating the tool performs no action on its own and that its return value is procedural guidance (screens, buttons, fields), which is the key behavioral fact. It stops short of describing error conditions or what happens on an unauthenticated browser session.

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 middle sentence carries the essential information and is front-loaded well, but 'from ChatGPT, Claude or any AI agent' is promotional filler and the trailing API note is cryptically phrased with an oddly future-dated check timestamp.

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?

With no output schema and no parameters, the description must carry the return-value burden, and it does indicate the result is a step-by-step guide executed via cotlet_browser_* tools. What is missing is any mention of how the target league/week is determined, which an agent would reasonably wonder about given the empty schema.

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 the schema baseline would be 4. However, the absence of any parameter for league, user, week or season is itself notable, and the description never explains that scope is derived from the active Cloud Browser session — a meaningful gap for a 'list' operation.

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 first sentence names a specific verb and resource ('List matchups in the user's own Sleeper account'), and the second sentence discloses the surprising real behavior: it returns step-by-step instructions rather than matchup data. That disclosure is what makes the tool distinguishable, though the 'List' framing still reads as a data-fetch at first glance and no sibling is named for contrast.

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?

There is real workflow guidance: 'opens nothing by itself; then do it with the cotlet_browser_* tools', which tells the agent this is a prerequisite step whose output is executed via browser tools. However, there is no statement of when to prefer this over sibling tools or when it is unnecessary, so usage is only implied.

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