save_to_library

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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so the write-and-safe profile is covered. The description adds genuinely non-structured context: the artifact becomes the next version at assets/<group>/<name>, appears on the Styles board where the user comments, and requires a playable preview. It stops short of stating overwrite/reversibility or error behavior.

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 sentences, all load-bearing, with the core action and its destination front-loaded. The cadence sentence is slightly wordy but still earns its place as the usage trigger.

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?

No output schema exists, so the description carries the burden and does so: it covers creation semantics, versioning, destination path, downstream visibility, and required file format. With all 7 parameters documented in the schema, an agent has everything needed to invoke this correctly.

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 100% schema description coverage the baseline is 3, but the description adds real constraints beyond the schema: the file must be a playable preview (.mp4 or .png), source_dir preserves the HyperFrames composition, and the note travels with the saved asset. This meaningfully enriches how file and source_dir should be supplied.

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 (keep/save) and resource (reusable part of an edit) in the style library, and enumerates concrete artifact types (title card, lower third, caption look, transition, cover layout, sound). An agent can distinguish this from snapshot-style siblings like get_library, create_style, and save_broll 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?

"Do it after each edit for every part a later video could use again" gives a clear trigger and cadence for using the tool. It does not, however, name when not to use it or point at an alternative sibling for related operations such as retrieving library contents.

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