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

Annotations only cover the generic safety profile (not read-only, not destructive, not idempotent). The description adds genuinely non-obvious traits: no account/email is created, the creator sees assigned posts and uploads through the link, and it consumes the plan's creator limit rather than a seat. No auth/error behavior is described, keeping it short of 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?

Four compact sentences, each carrying new information: mechanism, creator's experience, return value handling, and the sibling redirect. The link-handling instruction and the sibling note could be tightened, but nothing is padding.

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 two-parameter, no-output-schema create tool, the description covers the creation model, the quota impact, the returned artifact and how to present it, and the alternative tool. An agent has everything needed to call it and act on the result.

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 description coverage is 100% — both 'name' and 'access_code' are fully documented with defaults and display context. The description adds no parameter-level detail beyond the schema, so the 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 ('Add a creator (model)') and immediately defines the unusual mechanism — a private link with no account and no email. It also names the sibling to use for adjacent roles (create_crew_member), so an agent can distinguish it without opening schemas.

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?

Explicitly routes the agent: editors, clippers and posters go to create_crew_member instead. It also gives the post-condition instruction to keep the portal link in the answer, which is exactly the guidance an agent needs at call time.

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