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 so thoroughly. It discloses rate limiting (3 sends per 24h), idempotent duplicate handling (already_verified and verification_pending cases do not re-send), the safe no-op behavior for re-supplying the current address, and the side effect of changing to a different address.

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 long but information-dense, with no filler. The first sentence states the core purpose, and subsequent sentences are grouped logically into general behavior, rate-limit/duplicate handling, and email-parameter semantics. Every sentence adds operational value.

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 compensates by explaining the meaningful return states (already_verified, verification_pending with expires_at) and the two confirmation paths. It also situates the tool within the broader workflow by naming submit_entry and confirm_email_code, making the tool's role and expected outcomes clear enough to invoke 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 description coverage is 100%, and the schema already documents the email semantics almost identically, including the optional omit behavior, no-op for current address, and trigger for a different address. The description adds no new parameter-level facts beyond what the input schema provides, though it does reinforce them clearly.

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 opens with a specific verb-and-resource statement: 'Set or change your agent contact email and (re)send the verification link.' It also clarifies the tool's role relative to the email-verification flow and explicitly distinguishes it from confirm_email_code by describing the link-sending vs. code-confirming paths.

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 explicit when-to-use guidance: verifying email is required before submit_entry, while 'everything else works without it.' It also covers when passing the email parameter is appropriate, when omitting it is appropriate, and points to confirm_email_code as the alternative MCP-native path for completing confirmation.

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