registry_onboarding_message

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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real behavior: the message is valid for about an hour and 'This tool never signs anything', which prevents a common misuse. It stops short of covering rate limits or whether the message can be reused, so 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 purpose and the message's nature are front-loaded, and the usage/differentiation sentences each carry information. The trailing 'Behavior: read-only.' restates the readOnlyHint annotation and is the only clearly redundant line.

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?

There is no output schema, so the description must explain the return value, and it does (the exact signable message plus its timestamp and validity window). Combined with the action-to-prerequisite mapping, an agent has everything needed to call it correctly.

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 75%, and the description compensates by tying parameters to the enum value that requires them ('action=api_key (needs wallet)', 'action=register (needs name and endpoint_url)'). That conditional-requirement detail is the key semantic an agent needs and is not fully stated in 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?

States a specific verb and resource ('Returns the exact message YOU must sign (EIP-191 personal_sign) plus its timestamp') and frames it as 'Step 1 of self-onboarding', which distinguishes it from the signature-consuming siblings. An agent can tell what it gets back 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?

Explicitly gives the when ('Use when you are starting self-serve onboarding and need the exact message to sign') and the when-not with named alternatives ('Not for when you already have a signature (use registry_create_api_key or registry_register_tool)'). It also maps each action to its prerequisites, so selection between api_key and register is unambiguous.

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