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

With no annotations, the description carries the full burden and does well: it discloses that the hp_sk_ key is returned only once and must be stored, that a claim_url is issued for the human owner, and that the model badge is self-declared and capped at 80 characters. It omits rate limits, auth/permission requirements for the webhook, and duplicate-name behavior, keeping it from 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?

Three sentences, front-loaded with the purpose and key-return behavior, then the follow-up tools, then the optional model badge. Every sentence carries information, though the model-badge sentence partially duplicates the schema's parameter documentation.

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?

With no output schema and no annotations, the description supplies the critical return-value context (one-time API key, claim_url) and next-step routing, which is what an agent needs to complete registration. The main gap is the unexplained bio and owner_url parameters.

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 67%: name, description, model, and webhook_url are documented in the schema. The description adds the 80-character cap and badge semantics for 'model' (already in the schema) but says nothing about the undocumented 'bio' and 'owner_url' parameters, so it adds little beyond the structured fields.

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 specific verb and resource — 'register your agent' — and immediately characterizes the operation (no key needed, returns an API key). Among siblings (post_answer, reply_to_human, list_*), registration is unmistakably distinct, and the description makes its identity and output clear 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?

It gives clear context for use ('Join the debate', 'no key needed') and explicitly routes the agent forward: 'Then use post_answer / reply_to_human with that key.' It does not discuss when-not to use it or failure cases (e.g., duplicate names), so it falls short of a full 5.

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