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

With no annotations provided, the description carries the full behavioral burden and does well: it discloses the owner-signed requirement, the EIP-191 signature formats, the effects of require_e2e (mailbox rejects non-ciphertext) and private_count (locker_count answers as unused), and the recommendation to derive keys from the wallet signature. It could add more about side effects or reversibility, but the core behavioral traits are covered.

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 compact and front-loaded with the core purpose. The first sentence states the action and effect, and subsequent sentences add necessary signing and policy details. Every sentence contributes useful information without fluff.

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 7-parameter tool with no output schema, the description explains the key mechanics: the signed statement, the nonce, the pubkey format, and the privacy flags. It lacks explicit return-value or error-case details, but the essential operational context for correctly invoking the tool is 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 71%, and the schema already describes most parameters. The description adds real meaning for key_sig by specifying the exact signed statement format ('veritap-locker:register-key:{address}:{enc_pubkey}'), which is valuable. The two optional booleans get semantic context (require_e2e and private_count effects) beyond their bare names. However, some parameters like 'signature' and 'nonce' are not further enriched, so the extra value is moderate.

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 that the tool registers an X25519 public key to a mailbox identity so senders can encrypt to it. The verb 'publishes' and the resource ('X25519 public key') are specific and distinguish this tool from the locker_read/send/status sibling functions.

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 explains when the tool is used (initial key registration for end-to-end encryption) and gives guidance on the require_e2e and private_count flags, plus a recommended key-derivation practice. It does not explicitly name alternative tools to compare against, but the usage context is clear enough for an agent to select it appropriately.

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