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

Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds genuinely new behavioral context beyond them: a plan gating rule and a hard quota (up to 10 brands), which determines whether the call will succeed. It omits failure behavior when the quota is hit.

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?

Two short sentences, front-loaded with the core action and its constraint, then the next-step pointer. Nothing is redundant with the title or 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?

For a mutation tool with no output schema, the description covers preconditions and workflow but never says what is returned (e.g., the new brand id needed to call create_product) or how limit/plan violations surface. Adequate for invoking, incomplete for using the result.

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 schema already explains name, client_id (optional when only one client), description, and brand_colors. The description adds no parameter-level detail such as color format or name uniqueness, so baseline 3 applies.

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 ('Add a brand') and scopes it ('under a client'), which distinguishes it from siblings like create_client and create_product. It stops short of an explicit contrast with those siblings, but the noun/verb pair is unambiguous.

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?

Gives the eligibility condition (Agency plan, or Enterprise up to 10 brands) and the follow-on action ('Then create_product'), so an agent knows when this call is valid and what to chain next. It does not say what to do when the plan/limit condition fails, so it falls short of explicit alternatives/exclusions.

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