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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond those: codes expire in 24 hours and are invalidated by resend, cancellation, or editing the proposal — information the agent cannot get from structured 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?

Four compact sentences, front-loaded with the core purpose and followed by per-scenario requirements and expiry rules. Every sentence carries distinct, needed information with no filler.

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 destructive, multi-scenario mutation tool with no output schema and full param documentation, this covers purpose, per-flow requirements, and code lifetime. It stops short of describing failure behavior for expired/invalid codes beyond the expiry statement, so not quite complete.

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 baseline is 3. The description goes slightly beyond the schema by mapping which codes are required in which scenario and stressing that replacement needs both codes in a single call, a concurrency constraint the schema does not express.

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: 'Complete the pending email change,' and then enumerates the three flows (initial setup, replacement, removal). This clearly separates it from siblings like cancel_email_change and resend_email_verification despite the vague name/title 'Confirm notifications'.

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 explicitly states the condition per scenario: setup needs one confirmation, replacement needs both codes 'in the same call,' removal needs previous_confirmation only. That is strong context, though it never names an alternative tool or states when not to use this one.

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