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

Annotations cover the general safety profile (not readOnly, openWorld, non-idempotent, not destructive), and the description adds meaningful context beyond that: the code format and expiry, the consent prerequisite, and explicit non-behaviors (no subscription, no account-existence disclosure, no charge). This is valuable side-effect disclosure.

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 sentences, front-loaded with the trigger condition, followed by a crisp behavior summary and then non-behaviors. No wasted words; every sentence contributes to correct invocation.

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 side-effect tool with no output schema, the description covers the when, what, and not-what. It could mention next steps (e.g., using verify_email_signup) or return behavior, but annotations and sibling names make those inferable. The description is essentially complete for an agent 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 100%, so the description does not need to compensate. It reinforces the email and acceptance concepts already documented in the schema but does not add new parameter-level meaning beyond what the schema provides, so the baseline of 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?

The description states a specific action (sends a six-digit verification code) and the resource (CongressMCP account via email), and explicitly differentiates itself from siblings by noting it does not start a subscription or expose account existence. This makes the tool's purpose unmistakable relative to its siblings.

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 opens with a clear 'Use this when...' condition covering both account creation and recovery. It also names boundary behaviors ('does not start a subscription, does not expose whether an account already exists') that prevent misuse, though it does not explicitly name alternative tools for those cases.

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