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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so safety is covered. The description adds meaningful context beyond that: the response carries plan limits and billing state (credits_remaining, top_up_url, watermarked on free accounts), which tells the agent this call surfaces account/quota information. Minor overlap with the output schema, but the framing adds value.

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?

It is short, but the structure is poor: it opens with a dangling noun phrase, embeds a line break mid-token inside backticks, and mixes return-value enumeration into what should be a lead sentence describing the action. The most important instruction (call before brand_decision_required) is buried at the end rather than front-loaded.

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?

Complexity is low (zero params, output schema present), so the definition is close to sufficient. However, it never plainly states that it returns all brands for the account, gives no hint about pagination or ordering, and relies on the reader knowing what `brand_decision_required` is. Adequate but with visible gaps in framing.

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?

The tool takes no parameters, so per the baseline there is nothing the description needs to disambiguate. It correctly avoids inventing parameter guidance and spends its words on the returned data instead.

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 names the specific resource (the account's brands) plus the ancillary data returned (plan brand limit, credits_remaining, top_up_url, watermarked flag). It is written as a noun fragment rather than a verb phrase, so the 'list all' action is only inferred from the name/title. Still, the resource is unambiguous and distinguishable from siblings like create_brand or update_brand.

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 gives an explicit trigger: call this before answering `brand_decision_required` so the user picks a brand by name. That is a concrete when-to-use rule tied to a specific condition. It lacks any when-not guidance or comparison to list_products, but for a zero-param listing tool the routing signal is strong.

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