ClearBounce Email Verification

Verify Email Address

verify_email

Read-onlyIdempotent

Verify a single email address in real time with a live mailbox check. Returns status (deliverable, undeliverable, risky, unknown), a sub-status reason, a 0-100 quality score, and detailed checks (syntax, MX records, disposable, role-based, catch-all, typo detection). Costs 1 credit per call.

Input Schema

Name	Required	Description	Default
`email`	Yes	The email address to verify, e.g. jane@example.com

Output Schema

Name	Required	Description
`tip`	No	Present when many single checks arrive in a row: suggests verify_bulk for lists
`email`	Yes	The address that was checked
`score`	Yes	Quality score from 0 to 100
`checks`	No	Detailed checks: syntax, MX, SMTP, disposable, role, catch-all, typo, risk
`notice`	No	Present only when the account balance is low or empty
`status`	Yes	deliverable, undeliverable, risky or unknown
`subStatus`	No	Reason code behind the status
`isDeliverable`	Yes
`creditsRemaining`	No	Credits left on the account after this check

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 26, 2026

changedOutput schema / properties / notice / description

Previous value: -"Present only when the balance is low or empty: tells the user where to buy more credits"New value: +"Present only when the account balance is low or empty"

addedOutput schema / properties / tip

Added value: +{
+  "description": "Present when many single checks arrive in a row: suggests verify_bulk for lists",
+  "type": "string"
+}

Changed1 schema field changedSep 2, 2026

addedOutput schema / properties / notice

Added value: +{
+  "description": "Present only when the balance is low or empty: tells the user where to buy more credits",
+  "type": "string"
+}

First observedAug 29, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, and the description adds genuinely non-obvious behavior: it performs a live remote mailbox check (openWorldHint context) and consumes 1 credit per call. That cost disclosure is the kind of thing an agent cannot derive from annotations, though it doesn't cover rate limits or failure behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with the core action, then output shape, then cost. The enumeration of return fields partially duplicates the existing output schema, which is the only redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter tool with a full output schema and clear annotations, the description covers action, mechanism, and cost. The missing piece is explicit sibling routing, which keeps it from a 5.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Single required 'email' parameter with 100% schema description coverage including an example, so the schema fully carries parameter meaning. The description adds no syntax or normalization rules, which is acceptable at this baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb+resource ('Verify a single email address') with the mechanism named ('real time with a live mailbox check'). The word 'single' explicitly separates it from the sibling verify_bulk, so an agent can route correctly without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied by the word 'single' — there is no explicit statement telling the agent to use this rather than verify_bulk for batches or get_bulk_results/check_bulk_status for existing jobs. The alternative relationship is inferable but never spelled out.

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

All ClearBounce Email Verification tools Inspect

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