Upload Video

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

Adds substantial behavior beyond the annotations: uploads are resumable and report progress, category/language default inheritance with the 'none → 22' fallback, the call returns before YouTube finishes processing, and the hard quota cost (1 of 100 daily upload calls, plus up to 7 units). The async-after-return caveat is exactly the kind of trait an agent cannot infer from destructiveHint/idempotentHint alone.

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?

Front-loads the core action and its two traits in the first sentence, then spends the remaining sentences on default inheritance, async completion, and quota — every sentence supplies non-redundant information. No filler or restatement of the tool title.

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 13-parameter mutation tool with an output schema present, the description covers the gaps that matter: defaulting behavior, asynchronous processing, failure diagnosis path, and quota cost. Return-value detail is correctly left to the output schema.

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 parameters are already documented; the description goes further by explaining the semantic default behavior for the nullable category_id and language fields, which the schema does not state. It does not add meaning for the remaining booleans (ai_content, paid_promotion) since those already carry rich schema text.

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 ('Upload a video file from disk') plus distinguishing traits (resumable, reports progress), which separates it from update_video and set_thumbnail in the sibling list. An agent can identify this as the create-a-video operation without opening the schema.

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?

Gives clear context for when defaults apply (category/languages inherited from the last public upload, fallback to 22) and points to a follow-up step: 'Checking whether processing has finished tells you when, or why it failed.' It never explicitly excludes cases (e.g. use update_video for an already-uploaded video) and never names get_processing_status, so routing is implied rather than stated.

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