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

Annotations already declare write/non-idempotent/open-world behavior, and the description adds real value beyond them: the result lands on the account, it consumes one daily media allowance slot, and the returned `url` is accepted by any video input. The only blemish is an internal inconsistency between '3-30 s' and 'up to 20 s' that muddies the length contract.

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 tight sentences, purpose front-loaded before the WHEN clause, no padding. The trailing duration clause is duplicated with conflicting numbers, which is wasted and confusing text rather than excess length.

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 the trigger, the cost model, and the return value even without an output schema, which is enough to call it correctly. The contradictory duration limits (3-30 s vs up to 20 s) leave an agent unsure of the accepted source length.

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 a single parameter at 100% schema coverage, the schema already defines the input fully. The description adds only the passing note that any video input accepts the resulting `url`, which is about output, not the parameter itself, so 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+source: turns a TikTok link into a clip on the account. The TikTok-specific framing cleanly separates it from siblings like import_video and upload_media, and it says what comes back (`url`).

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 explicit 'WHEN: the user gives a TikTok link as a clip to use' gives a clear trigger condition. It stops short of naming import_video or upload_media as the alternative for non-TikTok sources, so the routing is clear but not fully closed.

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