save_broll

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

Annotations say readOnlyHint=false but destructiveHint=false, and the description adds meaningful side-effect context: it creates an APFS clone, and Gemini describes the clip in the background and injects description/keywords. However it doesn't describe what happens to the source or how the async Gemini process resolves.

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?

Single dense sentence front-loads the action and destination, with parenthetical clarifications kept short. It is information-dense but not wasteful.

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 mutation tool with no output schema, the description covers destination, naming, side effect (Gemini description), and the permission gate. It omits error behavior or what happens if the folder is new in more detail, but is largely complete.

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 description coverage is 100%, so the schema already explains each of the 4 parameters in detail. The description adds the destination convention and that the clip gets auto-described, but no additional semantics beyond 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?

Clearly states a specific verb and resource: 'Save a video of a session into the user's b-roll library.' It even names the destination path pattern and distinguishes itself from add_broll/list_broll by being the save-to-library operation. The sibling relationship with save_to_library (a similarly named sibling) is not addressed, leaving some ambiguity vs that tool.

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?

Explicitly gates invocation with 'Only on the user's ask,' which is a clear when-to-use rule, and names the sibling tools list_broll and add_broll to indicate a related workflow. It doesn't however state when NOT to use it vs save_to_library or add_broll, which are the closest alternatives in the sibling list.

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