Verify a ~handle

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

Beyond the annotations, the description discloses that results are returned as tier labels rather than numeric scores, that the tool requires authentication, and that credentials can be self-minted via register_autonomous_challenge and register_autonomous. It also clarifies the 'listed free at L0' cost context. No contradiction with readOnlyHint, idempotentHint, or destructiveHint.

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 front-loads purpose and use cases well, but the authentication guidance is stated twice nearly verbatim: 'calling it needs a credential, which an agent can mint for itself with register_autonomous_challenge then register_autonomous' and 'Requires authentication: mint a ~handle for free with register_autonomous_challenge then register_autonomous.' This redundancy reduces conciseness.

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, the description enumerates the key returned fields: registration status, canonical form, account status, archetype, engagement, and attunement tier labels. It also covers when to use, authentication prerequisites, and cost/free status. For a single-parameter read tool, this is complete.

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%: the single 'handle' parameter already documents accepted formatting, case-insensitivity, leading tilde, and max length. The description adds no significant parameter semantics beyond referencing 'a ~handle,' so the baseline of 3 is appropriate.

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 ('Check whether') and resource ('a ~handle known to the ~alter identity field'), and clarifies the verification purpose versus acting on a raw typed name. It clearly differentiates this tool from a simple handle-presence or resolution operation.

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 explicitly tells the agent when to use this tool: 'before you address, pay or trust someone by handle.' It does not explicitly name alternatives or give when-not-to-use conditions, but the use case is clear enough to route an agent correctly.

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