Upload captions

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

Annotations already declare this is a non-read-only, non-idempotent, non-destructive, open-world operation, and 'Add' is consistent with that profile. The description adds format and source-mode context but omits auth/channel requirements, quota implications, and duplicate-track behavior, so it goes modestly beyond the annotations without being rich.

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 front-loaded sentence that states the action, the accepted formats, and the two input sources with no filler.

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 an 8-parameter mutation with no output schema, the description covers the core action and input modes but leaves gaps around channel/auth behavior, quota cost, and the effect of duplicate or replacement uploads. Adequate but not complete for the tool's complexity.

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 63%, so the schema already documents most parameters. The description adds useful meaning for the file_path-versus-content choice and supported caption formats, but says nothing about name, language, is_draft, replace_existing, or channel semantics beyond what the schema provides.

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 states a specific verb and resource ('Add a captions track') and specifies supported formats and input sources. It is clear enough to distinguish from siblings like list_captions or delete_captions, though it never names an alternative explicitly.

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?

It implies usage when a caption file or inline subtitle content is available, but gives no when-to-use versus alternatives such as transcribe_video or download_captions, and no prerequisites such as channel selection or permissions.

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