Upload Caption

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

Annotations already declare readOnly=false, destructive=false, idempotent=false and openWorld=true, so the safety profile is covered. The description adds genuinely useful context in the quota cost (400 units) and the 100 MB/file format constraint, but omits behavioral questions the annotations don't answer, e.g. what happens if a track already exists for that language.

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 short lines: the operation first, the quota cost second. No redundancy with the title and no wasted words.

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?

Output schema exists so return values need not be explained, and the schema fully documents the six parameters. Annotations carry the mutation profile. The only real gap is the absence of any statement about duplicate/language-collision behavior or required permissions when adding a track.

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 every parameter (file, name, draft, video, language, my_channel) is already documented in the schema. The description adds only the SRT/VTT hint for the file format; it says nothing about the draft or name parameters that the schema does not already cover. Baseline 3 applies.

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 ('Add a caption track to one of your videos') plus the accepted source formats (SRT/VTT), so the operation is unmistakable. It does not contrast itself with the sibling update_caption or list_captions, so the agent gets no explicit disambiguation.

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?

No when-to-use or when-not-to-use guidance and no mention of the closest sibling, update_caption, which an agent could easily confuse with this tool. The description only implies the context (you have a caption file for a video) without stating it or naming alternatives.

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