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

Goes well beyond the annotations: it discloses that saved revisions are immutable, that references replace targeted bindings with '[] clears and omission inherits' semantics, that the current revision is required (optimistic concurrency), and that no credits are charged. These are exactly the mutation/cost behaviors an agent needs to call a write tool safely, and they are consistent with readOnlyHint=false, idempotentHint=false, and destructiveHint=false.

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?

Four dense sentences with no filler, front-loaded with the action and immediately followed by scope semantics, reference behavior, the concurrency requirement, and the explicit cost/scope exclusions. Every clause carries operational weight.

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?

An output schema exists, so return values need no explanation; the description covers everything else an agent must know for a 9-parameter write tool — scope routing, reference replacement rules, revision precondition, and absence of credit/picture/video side effects. Nothing material 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?

With 100% schema coverage the baseline is 3, but the description adds cross-parameter meaning the schema lacks: which fields are written under each scope value, and the replacement/clear/inherit semantics of referenceAttachmentIds. Individual parameter docs still live in the schema, so this is meaningful supplementation rather than full carriage.

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 ('Saves finished prompt text and existing uploaded references as an immutable storyboard revision') and immediately clarifies the scope split between whole/section and shot/still. The 'immutable revision' framing plus the final 'no pictures, video, planning model or credit charge' clause separates it cleanly from generation-oriented siblings.

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?

Usage is implied through the scope-based behavior mapping ('whole/section scope writes shared sectionDirection; shot/still scope...') and the prerequisite 'Requires the current revision', but the description never names an alternative tool (e.g. studio_storyboard_write or studio_storyboard_submit) or states when to prefer this over them. Adequate context, no explicit routing.

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