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

Annotations already declare the safety profile (not readOnly, idempotent, non-destructive, closed-world), so the description's job is to add context beyond them. It does: partial-update semantics for omitted fields, explicit exclusion of timing/names/pictures, and 'no generation or charge' to reassure the agent this is a free metadata edit rather than a billable generation.

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 tight sentences, front-loaded with the action and affected fields, each carrying information (target, partial-update behavior, exclusions, cost). Slightly clipped phrasing ('what for one existing ... section') costs it a point but there is no filler.

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 not be explained, and the description covers scope, partial-update behavior, and cost. For a 6-parameter mutation it stops short of noting the revisionId concurrency requirement (left to the schema) or failure modes, but an agent has enough to invoke 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 coverage is 67%, with the schema already documenting type, what, included, and revisionId. The description restates the writable fields ('included, type and/or what') but adds no syntax, format, or constraint detail beyond the schema, and leaves index and projectId undescribed in either place. Baseline 3 is appropriate for partially self-documenting parameters.

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 (updates) and resource (one existing 30-second storyboard section) and names the exact fields affected (included, type, what). This distinguishes it from read-only siblings like studio_sections_read and from other storyboard writers, though it does not explicitly name an alternative 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?

Gives clear scope guidance: it operates on a single existing section, omitted fields remain unchanged (partial update), and timing/names/pictures are explicitly out of scope. It lacks an explicit 'use X instead for timing/pictures' routing, so it stops short of a 5.

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