youtube_download

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

Annotations already declare it is a non-read-only, open-world, non-destructive operation. The description adds real behavioral detail beyond that: the >30 minute confirmation gate, the force bypass, and the automatic stream download-and-mux for video+audio. It omits what the tool returns and where confirmation appears.

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?

Four tight sentences, front-loaded with the core action and defaults, then escalating to selection options and the guard behavior. No filler sentences.

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 100% schema coverage, the description covers the important unknowns (defaults, guard, muxing). The main remaining gap is the return value and the quality-default inconsistency, but for a file-download tool this is largely 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?

Schema coverage is 100%, so the baseline is 3 and the schema already documents every parameter. The description adds normalization of the force parameter's purpose, but it also states 'Defaults to 720p quality' while the schema declares quality default 'best', a minor inconsistency that undercuts its added value.

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?

States a specific verb and resource (download a YouTube video or audio track to a local file) plus the supported scope (quality, type, format). This clearly separates it from read-only siblings like youtube_get_video_info and youtube_search.

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?

Explains defaults, quality/type/format selection, and precisely when the long-video confirmation fires and how force bypasses it. It does not explicitly steer the agent away from sibling download-like tools such as youtube_clip, but the context is otherwise clear.

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