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

Annotations already carry the safety profile (destructiveHint=true, idempotentHint=false, readOnlyHint=false), so the bar is lower, and the description adds real value by explaining the brandKitId side effect: binding it re-themes every future render of the project. That is non-obvious behavior beyond the annotations and schema.

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 front-loaded sentences: purpose and fields first, invocation second, side effect and return value last. No padding or redundant restatement of the schema.

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?

With annotations covering safety, a full output schema handling returns, and 100% schema coverage, the description is nearly complete; the only untold detail is the nested `format` sub-fields (fps/resolution/aspectRatio), which the schema carries.

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 100%, so the baseline is 3, but the description adds meaning by clarifying how `body` should be used (only the changed fields) and by explaining the semantic effect of brandKitId rather than merely restating its type.

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 (Update) + resource (project) and enumerates the mutable fields (name, format, brandKitId), which cleanly separates it from update_brief and update_component. It also names the return type (ProjectResponse), so an agent knows exactly what the call does without opening the 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?

It gives invocation mechanics ('Pass projectId + the changed fields as `body`') but never says when to reach for this versus siblings like update_brief, update_component, or create_project, nor any preconditions. Usage is implied rather than stated.

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