parse_youtube_url

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

The description states the core behavior: parsing URLs and extracting identifiers plus timestamps. With no annotations present, it could go further by describing the return structure or behavior on invalid input, but it does not mislead and clearly conveys that the tool is a read-only parsing operation.

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?

Two tight sentences: the first captures the operation and outputs, the second lists supported formats. Every element earns its place with no filler or redundancy.

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 one-parameter pure parsing tool, the description covers accepted inputs and extracted outputs, and sibling differentiation is achieved. The lack of an output schema is partly mitigated by listing the exact fields returned, though exact property names and invalid-input behavior are left implicit.

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%—the single 'url' parameter is already described as 'Any YouTube URL or video ID.' The description adds useful format examples, but these are illustrative rather than essential, so the baseline of 3 is appropriate.

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 precise verb ('parse'), a specific resource ('YouTube URL'), and the exact extracted outputs (video ID, channel ID, playlist ID, handle, timestamp). The listed URL formats make it immediately distinguishable from sibling tools, which operate on transcripts, metadata, or channel data rather than URL parsing.

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?

Explicitly enumerates the accepted input formats (youtube.com/watch, youtu.be, /shorts/, /embed/, /playlist, /channel/, /@handle, and bare video IDs), telling an agent exactly when this tool applies. It does not name an alternative, but no sibling performs URL parsing, so the applicability is clear without exclusions.

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