Update Playback Customizations

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

Beyond the annotations, the description discloses several high-value behavioral traits: partial-update semantics, that sending a field as null deletes it and reverts to default, the exact permission scopes needed, the confirm=true requirement, and the side effects ('May share access, notify people or incur provider charges'). This substantially exceeds what destructiveHint/idempotentHint already convey.

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?

The core purpose and null-deletion behavior are front-loaded in the first sentence, with the permission/auth details kept in a separate structured block. It is appropriately sized for a 44-parameter tool, though the permissions section is somewhat bulky.

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 complex mutation tool with 44 parameters, nested objects, and no output schema, the description covers purpose, mutation semantics, auth, confirmation, and side effects well. Return-value/response behavior is not addressed, but with no output schema this is a minor gap.

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 the baseline is 3, but the description adds meaning the schema does not: null values delete a field and revert to default, which is critical semantics for any of the 44 parameters. This is meaningful added value beyond the per-field 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 ('Applies a partial update') and resource ('a video's playback customizations'), and the 'playback' qualifier clearly separates it from the many sibling customization tools (update_customizations, update_thumbnail_customizations, etc.). It is clear but does not explicitly name or contrast with those siblings.

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?

The description implies the tool's context through its mutation semantics and permission requirements, and requires confirm=true, but it never states when to prefer this over update_customizations or the other customization updaters, nor when not to use it. Usage is implied rather than prescribed.

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