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

Adds strong context beyond the annotations: only classification columns change, they are marked manual so auto-classification won't overwrite, and metrics/analysis/the video itself are untouched and nothing is published. This is genuinely useful mutation-scope disclosure. It slightly softens the destructiveHint=true by scoping the change, but the null-to-clear path explains the destructive flag.

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?

Three dense sentences, front-loaded with the action and identifier, then the input rule, then the mutation scope. No filler, and each clause earns its place.

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?

Covers action, inputs, mutation scope, and even the return value ('Returns the video's resulting classification') despite no output schema. Complete enough for safe invocation; only brandId's role is left implicit.

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?

With 0% schema description coverage, the description carries the load: it explains funnel's enum (tofu|mofu|bofu), describes format as a taxonomy slug with concrete examples (talking_head, tutorial, listicle), and identifies communicationStyle as a style slug, plus the null-clears semantics. brandId remains unexplained, keeping it from a 5.

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?

Specific verb (classify) plus resource (video) and the exact axes being set: funnel, format, communicationStyle. It even names the identifier (platformVideoId) and the enum values for funnel, so an agent knows precisely what this tool manipulates versus generic update_video or analyze_video 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?

Gives clear usage conditions: 'Provide at least one; pass null to clear an axis back to unclassified.' That covers the input contract well, but it does not route the agent away from any sibling (e.g., when to prefer this over update_content or analyze_video).

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