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

With readOnlyHint=false, annotations already signal mutation; the description adds genuinely useful behavior: omitted fields are preserved, review_state should only be confirmed after user approval, and the updated kit is returned. This goes well beyond the annotation burden and prevents an agent from assuming full replacement semantics.

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 short sentences with no filler; the core behavior is front-loaded and each sentence adds distinct information: scope, mutation semantics, guardrail, and return value.

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?

Despite nine parameters and nested objects, the description covers the essentials that the schema and annotations do not: partial-update semantics, the review_state approval rule, and the return type in the absence of an output schema. Nothing an agent needs to safely call it appears 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?

Schema coverage is 67%, so the schema carries a fair amount, but the description adds the critical partial-update rule that applies to every parameter and explains the otherwise undocumented review_state enum. It could enumerate a few more fields, but it compensates for the main gaps.

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?

Opens with a concrete verb-resource pair ('Change fields on a brand kit') that immediately distinguishes update from sibling create/extract/get/list operations. The partial-update clarification tightens scope further, and mentioning the return value removes ambiguity about what the call produces.

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?

The description gives clear usage context: it is for modifying an existing kit rather than creating or extracting one, and it carries an explicit approval condition for setting review_state. It does not name alternative tools or state when not to use it, so it stops just short of the top score.

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