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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is baseline-covered; the description adds the crucial non-derivable fact that the deletion is irreversible ("Cannot be undone") and names the underlying endpoint. It stops short of saying what happens to videos/images that reference the element or what permissions are required.

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 short, front-loaded sentences with zero filler: effect, irreversibility warning, and endpoint. Nothing could be removed without losing information.

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 destructive delete with no output schema, the definition covers what the agent needs: identity of the target, the irreversibility warning, and the account-scoping parameter documented in the schema. Residual gaps (referential side effects) are minor.

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% with only two parameters, so the schema already documents both; the description adds the useful framing that elementId must refer to one of the caller's own elements (implying the account/email scoping). That is a small but real addition over the schema's bare "The element id (u_…)".

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 (Delete) and resource (one of your elements, ID prefix u_…), which cleanly separates it from the sibling deletes targeting avatars, voices, tasks, and uploads. An agent can pick it 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?

Usage is implied rather than stated: the description makes clear it applies to element IDs (u_…) and the agent must already have one. It names no alternatives (e.g., kling_delete_avatar or kling_delete_uploads) and gives no when-not conditions, so routing among the delete siblings is left to inference.

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