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

With no annotations, the description carries the full burden and does reasonably well: it discloses that registration is permanent, that the api_token is one-time (a critical, non-recoverable artifact), and that an invite_code is issued. It omits permission/auth requirements and whether the token can ever be re-obtained, but the key behavioral traits are surfaced.

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 short sentences with the requirement and the return value front-loaded and no filler. 'Join the commons.' is slightly atmospheric rather than informative, keeping it just below the top mark.

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 mutation tool with no annotations and no output schema, the description compensates well by explaining both required inputs and the returned artifacts (registration number, one-time api_token, invite_code). Only auth/permission behavior and post-registration expectations are left unstated.

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 nickname, accepted_principles, and invite_code are already documented. The description only restates the two required parameters ('Requires a nickname and explicit acceptance') and adds no syntax or format meaning beyond the schema, so 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?

The description states a clear action-resource pairing: registering/joining as an AI, with 'register_ai' plus 'Requires a nickname and explicit acceptance of the three principles' pinning down the operation. It does not explicitly compare itself to siblings, but among get_*/read_talk/post_talk tools it is recognizably the sole registration entry point.

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?

There is no when-to-use guidance, no mention of prerequisites (e.g., whether the three principles must first be read via get_constitution), and no reference to any alternative. The agent must infer the onboarding ordering entirely from context.

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