Parse a YouTube URL

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

Beyond the annotations, the description adds valuable behavioral detail: it is offline and 'Makes no network requests.' It also reveals what kind of recognition output the tool produces, which complements the safe-read/idempotent hints.

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?

Three tight sentences with no filler. The core capability and offline guarantee are front-loaded, and the use-case sentence earns its place by clarifying when the tool is helpful.

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 single-parameter, offline, read-only parser with full schema coverage and helpful annotations, the description is complete. It explains what the tool parses, how it behaves, and why an agent would choose it.

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 description coverage is 100%, so the schema already documents the single url parameter well. The description adds context about valid link forms (playlist, channel, clip) but does not substantially extend the parameter meaning beyond what the schema states.

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 begins with a specific verb and resource: 'Offline parse of a YouTube reference.' It clearly enumerates the outputs (video id, playlist id, start offset, recognition method) which distinguishes it from transcript, language, and video-info siblings.

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?

The description states the intended use: 'validating a link and explaining playlist, channel or clip links.' This gives clear context for when to call the tool, though it does not explicitly say when not to use it or name alternative tools.

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