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

Annotations declare destructiveHint=true, openWorldHint=true and non-idempotent, and the description fills in the specifics the annotations can't: it is FREE, redo draws from a fair-use budget (`redos_left` per film), frames keep voiceover timing so only pictures move, and the result comes back renumbered with new `sheets`. That is real behavioral context beyond the structured hints.

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?

Front-loads the frame-number concept and the FREE/constraint information before the operation list, and the backticked shapes pack a lot of precision per token. It is a single dense block, though, and the embedded quoted example plus parentheticals make it heavier than it needs to be.

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?

Given 7 params, nested objects, destructive semantics and no output schema, the description covers the missing pieces: which operations exist, that exactly one may be sent, how renumbering/return values work, and what the paid alternative is. An agent has everything needed to call it 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?

Schema description coverage is only 29% and the schema is a bag of nested objects with no discriminator, yet the description spells out every operation's payload (redo {frame, note}, move {frame, to}, remove {frame}, insert {after, note}, retitle {frame, title?, note?}) and adds semantics the schema lacks — notably 'after: 0 puts it first'. The two top-level params are already documented in-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+resource: 'Change the film's picture storyboard by frame NUMBER', with the exact data path (picture_storyboard.frames[].n) and a natural-language example. It explicitly distinguishes itself from the sibling studio_video_storyboard ('For a whole new storyboard use studio_video_storyboard').

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?

Enumerates the five mutually exclusive operations and the exact payload shape for each, plus the constraint 'Send exactly ONE of' — critical since the schema has no oneOf enforcement. It also routes the whole-storyboard case to studio_video_storyboard and warns that a re-plan 'has a price'.

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