list_watches

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

With no annotations, the description carries the full burden, and it does add real value by disclosing that results are cached and re-watching is instant. However, it does not clarify that this is a read-only enumeration, whether results are ordered or limited, or how it relates to starting a watch.

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?

A single compact sentence with zero waste, and the core concept (previously watched videos) is front-loaded. It is arguably too terse rather than bloated, but structurally efficient.

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 needn't be explained, and there are no parameters to document. Still, for a history-listing tool sitting among many viewing siblings, the description omits how it should be chosen over watch or live_watch_for, leaving a meaningful gap.

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 baseline of 4 applies; nothing in the description is needed to explain inputs, and it introduces no misleading parameter expectations.

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 the resource (previously watched videos) but uses a noun phrase with no explicit verb; the listing action is only inferable from the tool name. An agent can guess it returns watch history, but it isn't stated as 'list all watched videos' and there is no differentiation from siblings like watch or live_watch_for.

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 when-to-use guidance, no exclusions, and no reference to any of the many siblings (watch, live_watch_for, search, look). The agent must infer that this is the history-listing tool entirely on its own.

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