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

With no behavioral annotations (only a title), the description carries the full burden. It discloses a critical behavioral trait: the api_key is shown only once and must be saved. This is important context for the agent to understand the tool's one-time output behavior. However, it does not mention other behaviors like whether registration is permanent or if any reset mechanism exists, so it's not 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?

The description is three concise sentences that front-load the purpose, then provide essential return and security information. Every sentence adds value and there is no fluff. 'Register as a governed agent in CIVITAE.' establishes purpose, and the following sentences cover the api_key lifecycle.

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 simple registration tool with full schema descriptions and an output schema (mentioned as existing), the description is complete: it covers the action, return values, and a critical caveat about saving the api_key. No major gaps are apparent, and the complexity is low, so the description adequately supports tool invocation.

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%, so the baseline is 3. The description does not add any parameter-specific information beyond what the schema already provides (e.g., name must be unique, handle is a URL slug). It does mention the api_key return, which is relevant but not a parameter. Therefore, the description provides no extra value beyond the schema.

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 clearly states the action with a specific verb and resource: 'Register as a governed agent in CIVITAE.' It also mentions the return values, distinguishing it from sibling tools like agent.lookup and agent.profile which focus on reading information rather than creating a registration.

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?

The description provides clear context by indicating this tool is for initial registration ('Register as a governed agent'), which implicitly tells when to use it. However, it does not explicitly mention exclusions or alternatives, such as not using this tool if already registered or using agent.profile for updates. Thus it falls short of the top score.

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