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

Beyond the annotations (readOnlyHint false, idempotentHint true, destructiveHint false), the description discloses real behavioral traits: transactional atomicity ('all supplied edits succeed together or the prior board is restored with a refusal identifying the failed section'), server ownership of index/count/name/timing/pictures, and the absence of credit cost. This is meaningful context an agent could not derive from the annotations alone.

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, then atomicity, then cost. Little waste. The only slight redundancy is restating the 'what, type and included' fields that the schema already labels.

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 described, and annotations cover the safety profile. The description adds the atomic rollback semantics and server-owned-field scope, which are the key things an agent needs. The gap is the unexplained projectId and the exact role of index.

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 50%; the sections sub-properties are documented in the schema, and the description echoes them ('what, type and included fields'). However, projectId is undocumented in both schema and description, and the description does not clarify how 'index' identifies a section despite calling it server-owned. Baseline 3 fits given partial coverage.

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+scope ('Updates the supplied existing 30-second storyboard sections') so the agent knows this mutates existing sections rather than creating or generating them. It does not, however, explicitly differentiate from close siblings like studio_sections_update or studio_storyboard_submit, so the reader must infer the boundary.

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?

There is no explicit when-to-use or when-not-to-use statement, and no named alternative among the many storyboard/section siblings. The 'No generation or credit charge' clause hints at a boundary (this is a free edit, not a paid generation) but usage is only implied.

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