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

Annotations already convey mutability (readOnlyHint=false), idempotency, and non-destructiveness. The description adds valuable behavioral context by clarifying this is a partial patch, that only the active profile is mutated, and that profile selection/creation is outside this tool. No contradiction with annotations.

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 action and resource are front-loaded, the usage context is in the second sentence, and the boundary condition is in the third. Every sentence earns its place.

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?

Since an output schema exists, omitting return-value details is acceptable. The description covers what can be patched, when to use it, and the key limitation that profile selection/creation is web-app only, making it self-sufficient for correct invocation.

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 0% schema description coverage, the description must compensate, and it does by mapping business concepts to schema fields: voice→brandVoice, themes→mainThemes, hashtag set→preferredHashtags, audience-size estimates→audienceSize, plus expertise areas, personality traits, and bio. It does not detail the nested audienceSize structure, but the mapping is sufficient for practical use.

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?

The description opens with a specific verb ('Patch') and a precise resource ('the user's active brand profile'), then enumerates the affected fields. This clearly distinguishes it from sibling update tools by naming the resource and the active-profile scope.

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 explicitly frames when to use the tool: when the user wants Claude to refine their brand voice from a transcript, style guide, or competitor analysis 'without leaving the conversation.' It also states a clear exclusion—profile selection/creation must happen in the web app—so the agent knows not to attempt those here.

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