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

Annotations already declare non-read-only, non-idempotent, non-destructive, so the description's job is to add context — which it does by saying the copy includes all clips and the original is untouched, and by disclosing the return value ('the new cut') even though no output schema exists. Missing details like naming of the copy or permissions keep it from a 5.

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: the action comes first, the motivation second, and the return value last. No filler or repetition of the title.

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 simple two-parameter duplication tool with full schema coverage and annotations covering the safety profile, this is nearly complete — the return value is stated despite no output schema. Only minor operational details (copy naming, where the new cut lands) are absent.

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% and each parameter even documents its provenance (get_timeline, list_threads), so the baseline is 3. The description adds no parameter-level meaning beyond the schema.

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 and resource ('Copy a cut with all its clips') and clarifies the scope of the copy. It differentiates from create_cut implicitly by framing this as duplication of an existing cut, though it never names the sibling.

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 clause 'so you can try a different edit without changing the original' gives a concrete condition for choosing this over editing in place. It stops short of naming alternatives such as create_cut or add_clips_to_timeline, and gives no exclusions.

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