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

Annotations only declare the generic write/safety profile (readOnly=false, destructive=false, openWorld=false). The description adds substantial context beyond that: it queues processing, returns id and status, the final outcome is settled asynchronously (processing or pending_credits on out-of-credit teams), and it errors if bytes were not uploaded. That is the async, credit-gated behavior an agent must know.

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-loaded with the action, then prerequisites, return values, and the error/retry case, each in a compact sentence. No filler or repetition.

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?

With no output schema, the description carries the burden of describing returns and does so (id and current status), plus the async settling behavior and the credit-gated outcome. Nothing an agent needs to invoke or interpret this call is missing.

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% and the single parameter's schema text nearly duplicates the description's explanation, so the description adds little parameter-level detail. The only extra value is the sequencing constraint (PUT bytes before passing the id), which borders on usage rather than parameter semantics. 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+resource ('Finish an upload started with create_upload and begin processing') and immediately ties itself to the sibling that precedes it. An agent can distinguish it from create_upload and submit_video without opening any 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 explicit preconditions ('AFTER you have PUT the file bytes to its upload_url'), names the creating sibling (create_upload), and routes status checking to another sibling (poll get_video_status). It also states the failure case ('If the file hasn't been uploaded yet, an error is returned: upload it, then retry').

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