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

Annotations already declare non-read-only, idempotent, non-destructive, so the safety profile is covered. The description adds real behavioral value beyond that: unset fields are preserved unless explicitly emptied, which is the merge/patch semantics an agent must know before writing a partial update.

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, front-loaded with the action, then the invocation pattern, then the edge-case rule. No padding or restatement of the tool name.

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 no explanation, and the mutation semantics plus parameter usage are covered. What is missing is any note on required permissions or what happens to nested fields not present in the supplied object beyond the clearing rule.

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 description coverage is 100%, so the baseline is 3. The description goes beyond the schema by explaining the section/field pairing and the empty-list clearing convention, which changes how the voice/visual object parameters should be populated.

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 and resource ('updates the brand voice ... or brand visuals') and enumerates the field families each covers (tone, do/don't, vocabulary vs colors, fonts, logo usage). This is enough for an agent to distinguish it from read-side tools like get_brand_context and unrelated mutations like update_asset or update_channel_settings.

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?

Tells the agent how to invoke it ('Pass section=voice or section=visual plus the fields to write') and gives the conditional rule for clearing fields. It does not explicitly state when not to use it or name a sibling alternative, so it falls 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.