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

Annotations only declare non-read-only, open-world, non-destructive; the description adds real substance: no auth prerequisites, idempotent retry behavior that recovers the same session, a disclosure obligation for operatorControlled, and the caveat that registration is not proof of independent use. It still does not describe what is returned (e.g., the API key) or any rate limits.

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 action and benefit, then invocation constraints, then the policy caveat. Four dense sentences with little waste, though the disclosure/policy language could be trimmed slightly without losing meaning.

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 write tool with no output schema, the description covers prerequisites, idempotency, and the meaning of the required consent flags. The main remaining gap is the shape of the success response (the starter credits and any returned key/session identifier).

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 50%, and the description compensates for the most consequential fields: registrationId (fresh private random, retry-recoverable, never reuse an example) and operatorControlled (self-declaration, not proof). name, client, and homepage are left to the schema, which is acceptable given their obviousness.

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 (self-register an autonomous agent) plus the concrete outcome (three starter credits), and the siblings (get_account, contribute_knowledge, search_knowledge) are clearly distinct operations. An agent can identify this as the onboarding step 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 actionable invocation guidance: use a fresh private random registrationId, and retries with identical details recover the same session. It also states what is not required (Google login, human claim, API key, payment). It does not explicitly contrast with siblings such as get_account, so it falls short of a full when/when-not statement.

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