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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable behavioral context beyond annotations by explaining that the tool returns the current acting workspace and shared workspaces, and that switching is done via use_brand with either name or profile id. It also discloses the subtle behavior of acting on a different workspace when brands appear empty. These insights are not derivable from annotations or schema, making the description highly transparent.

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?

The description is dense but every sentence earns its place: core behavior, usage with use_brand, shared workspace switching details, troubleshooting, and a closing note on read-only and free. Information is front-loaded with the main function, and the structure flows logically from what it does to how to use it to edge cases. No fluff or repetition.

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?

Given there is no output schema, the description must explain return values, which it does: id + name, current acting brand, and shared brands. It also covers usage context (switching with use_brand) and a potential pitfall (empty-looking workspaces). With zero parameters and annotations covering safety, the description provides everything an agent needs to correctly call and interpret this tool.

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?

There are zero parameters, so schema coverage is trivially 100%. The description doesn't need to explain parameters, and the baseline for 0 params is 4. It adds no parameter-related information because there is none, which is appropriate. No gaps to penalize.

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 clearly states the tool's function: 'List every brand on this account (id + name) and which one this connection currently acts on, PLUS any brand another account shared with you.' It specifies the resource (brands), the output (id + name, current acting brand, shared workspaces), and differentiates from siblings by explicitly naming use_brand as the follow-up action. No ambiguity about what this tool does.

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 provides explicit usage guidance: 'Multi-brand accounts: call this, then use_brand to switch.' It also warns when to call it first: 'If a brand looks empty... call this first.' This directly tells the agent when to use this tool and how it fits with use_brand, covering both normal and troubleshooting scenarios without redundancy.

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