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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered without prose. The description adds one genuine piece of context beyond that — results are scoped to the current API key and limited to 'active' watches — but does not explain what 'active' excludes (expired, paused, triggered), which is the main behavioral question here.

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?

It is certainly short with no padding, but it is a sentence fragment rather than a well-formed, front-loaded description, and the brevity comes at the cost of under-specification. There is no wasted text, yet the single fragment is doing too little work.

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?

An output schema exists, so return values need not be described, and with zero parameters the schema burden is nil. Still, for a list tool whose only real ambiguity is what 'active' means and how results relate to watch_tool/unwatch_tool, the description leaves an agent guessing.

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; the baseline of 4 applies. The description neither helps nor hurts parameter understanding.

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 fragment 'Active watches on this API key' nominally identifies the resource (watches) and scope (API key), and the title supplies the missing verb 'List'. However, the description itself never states the verb, and it does not distinguish this list operation from siblings like watch_tool or unwatch_tool that operate on the same resource.

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 no guidance on when to call this versus alternatives such as unwatch_tool, nor any prerequisite or context statement. The only implicit usage signal is the word 'Active', which hints at filtering but is never explained or contrasted with any sibling.

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