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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description adds the real behavioral consequences: the previously active version is archived but reactivatable, library pillar tags follow the active version's pillars, and the call consumes no credits. These are non-obvious side effects an agent could not infer from the schema or annotations.

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 tight sentences: effect first, then the archiving/pillar consequence, then routing to siblings and the return value. No filler, and the most important fact (what becomes active) is 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?

For a one-parameter state-change tool with no output schema, the description covers the mutation's effect, its side effects on the prior version and pillar tags, cost, and the return payload (brief_id and active version). Nothing needed to call it correctly is missing.

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 coverage is 100% and the single brief_id parameter is already documented as coming from build_creator_brain or get_creator_brain. The description adds no format or constraint detail beyond that, so the schema carries the load and 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: makes a built Creator Brain version the active one used by every new draft. It is clearly distinguishable from build_creator_brain (creates) and get_creator_brain (reviews), both named explicitly.

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 an explicit sequencing rule ('Use it after reviewing a build with get_creator_brain') and names the alternative for the adjacent action ('to build a new version use build_creator_brain'). The agent knows both when to call it and when to call a sibling instead.

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