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

Beyond the readOnlyHint/destructiveHint annotations, the description discloses the cost profile ('Uses no credits'), the returned fields (brief_id, version, status) and the full status vocabulary (building, draft, active, archived, failed), plus the fact that the Brain is derived from documents. That is real context an agent needs for a review-then-activate workflow.

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?

Front-loaded with the purpose before the alternative-tool routing, and every clause maps to something an agent needs (contents, default behavior, workflow, return shape, cost). The first sentence is dense with an enumeration that could be trimmed, but nothing is redundant.

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?

There is no output schema, but the description compensates by naming the key returned fields and status values. For a single optional-parameter read tool, the description covers contents, defaults, workflow position, return shape and cost — nothing material 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%, so the baseline is 3; the description earns a step up by explaining the meaning of the optional brief_id in workflow terms — it selects a pending build surfaced by build_creator_brain rather than the active Brain, and is the input to a subsequent activate_creator_brain call.

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 ('Shows the creator's Creator Brain') and then enumerates exactly what the brief contains — identity, audience, offers, proof, stories, content pillars with pillar ids, voice rules, status, source documents. It explicitly contrasts with the sibling get_creator_profile, so an agent can distinguish it without opening the 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?

Gives explicit routing rules: omit brief_id to read the active Brain; pass the brief_id from build_creator_brain to review a new build before calling activate_creator_brain; use get_creator_profile for profile basics. Both the when-to-use and the when-to-use-something-else conditions are named.

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