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

Annotations already mark idempotentHint=true, and the description adds useful behavioral detail by confirming re-signing the same address is safe and yields status already_recorded. It also discloses the privacy-relevant behavior that the tool records the address the user provides, which goes beyond the annotation fields.

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 short sentences, each earning its place: purpose, consent/privacy warning, idempotency reassurance, and an alternative path for urgent cases. No filler or redundant restatement of schema content.

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 simple signup tool with a full schema, output schema, and idempotency annotation, the description covers purpose, consent, idempotent behavior, and the main exclusion. Optional parameters need no extra prose because the schema already describes them.

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 description coverage is 100%, so the baseline of 3 applies. The description adds minimal parameter-specific meaning beyond associating 'email' with 'the address they give you'; the schema already documents all four parameters adequately.

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 and resource: putting a user on the free public beta's notification list for paid API keys. This clearly distinguishes the tool from all listed siblings, which are about allele/HLA matching and verification rather than signups.

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?

The description gives clear when-to-use context ('Put a user on the free public beta's notification list') and an explicit when-not-to-use instruction (higher rate limit today -> email hello@hlaverify.com instead). It also adds a mandatory precondition: ask before calling because the address is recorded.

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