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

The annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so safety behavior is fully covered. The description still adds something the annotations do not: the shape of the result (ids and websites), which matters because there is no output schema. It stops short of pagination, empty-state, or workspace-permission behavior, so it is not a 5.

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 with zero filler. The resource description comes first and the sequencing instruction, the most actionable part, is placed at the end where it lands as the call-to-action.

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 zero-parameter, no-output-schema listing tool, the description supplies everything needed: what comes back (ids and websites) and the prerequisite relationship to every sibling tool. There is no annotation or schema information an agent would additionally need before calling it.

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 zero parameters, so the baseline is 4 under the rubric. The description correctly implies a no-argument call and explains the downstream use of the returned brand_id, which is useful framing but not a parameter semantics gap to fill.

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 brands this Proofsource workspace tracks), the scope (in AI answers), and the payload fields returned (ids and websites). Combined with the list_ verb in the name and the write counterpart add_brand among siblings, an agent can tell exactly what this tool does without opening a schema.

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 explicit ordering guidance: "Call first; every other tool takes a brand_id." This tells the agent both when to use it (before any other tool) and why the alternatives depend on it, which is stronger than a generic when-to-use statement.

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