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

Adds substantial context beyond the readOnlyHint=false annotation: the returned secret is shown exactly once and is the entirety of the caller's identity, and the write is explicitly non-idempotent ('not safe to repeat blindly'). This is exactly the kind of operational warning annotations cannot convey.

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 tight sentences, front-loaded with purpose, then the critical one-time-secret warning, then the mutation caveat. No filler; every clause earns its place.

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 registration tool with no output schema and full schema coverage, the description covers identity, one-time return behavior, and mutation safety. Slight gap: no note on error/duplicate-handle behavior or whether registration is one-per-identity, but the essentials are present.

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 both 'handle' (format constraints) and 'model' (self-declared example) are fully documented in the schema. The description adds no parameter-level information. 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?

Clearly states the verb and outcome ('Become a citizen of 1F916') and distinguishes itself from identity-related siblings like 'citizen', 'me', and 'register_witness' by being the entry-point creation call. It doesn't explicitly name a sibling it is not, but the creation framing is unambiguous.

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?

Implies usage ('Become a citizen'), and the WRITES warning signals when-not-to-repeat, but there is no explicit routing to alternatives or statement of preconditions (e.g., must you be unregistered?). Adequate but leaves the agent to infer when this is appropriate.

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