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

Annotations already declare readOnly=false, idempotent=true, destructive=false, but the description adds substantive behavior beyond them: the copy lands in the project's media pool at the Library root, no API key or external fetch is involved, and re-adding an existing sample returns its existing mediaRef rather than duplicating — which concretely explains the idempotentHint.

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?

One paragraph, front-loaded with what the samples are and immediately followed by the two call modes. The parenthetical listing the clip types earns its place by telling the agent which sample suits which downstream task (transcripts, captions, b-roll).

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?

There is no output schema, and the description compensates by describing the return shape (a mediaRef per added item, existing ref on duplicates) and the destination of the copy. With four parameters, two required, and full schema coverage, nothing an agent needs in order to call it correctly is missing.

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 baseline is 3, but the description adds operative semantics the schema only hints at: the no-ids call is a list operation (not an error), all:true is an alternative to enumerating ids, and the per-result mediaRef is the handoff value for add_clips.

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?

The description gives a specific verb and resource (add/copy sample media into the project's media pool) and enumerates the asset types (talk clip, b-roll, photo, music bed). It also distinguishes the two modes — listing versus copying — and points to the sibling add_clips as the consumer of the returned mediaRef, so an agent can separate this tool from download_stock_media or search_media without opening a 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?

It states the situation clearly ('for trying the editor without your own footage') and gives exact call conditions: omit ids to list, pass ids or all:true to copy. What's missing is an explicit when-not or a named alternative tool — 'no download from elsewhere' only implicitly contrasts with download_stock_media/download_sound.

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