ClearBounce Email Verification
Server Details
Verify email addresses in real time and find business email addresses with live mailbox checks.
- Status
- Healthy
- Uptime
- 92.6% over 78 days
- Last Tested
- Transport
- Streamable HTTP · MCP 2025-11-25
- URL
- ChatGPT
- –
- Claude
- –
TDQS
Scored across 6 tools
Each tool maps to a distinct action/resource: single verify, bulk start, bulk progress, bulk per-address results, credit balance, and email discovery. The only potential overlap (check_bulk_status vs get_bulk_results) is explicitly resolved in the descriptions, which distinguish progress/summary from per-address results.
All six tools follow a consistent snake_case verb_noun pattern (check_*, get_*, find_*, verify_*). The bulk/email suffix distinction (verify_bulk vs verify_email) reinforces rather than breaks the convention.
Six tools is well-scoped for an email verification service: one tool per lifecycle stage with no filler. find_email is the only slightly tangential addition but it's a natural companion to verification.
The verification lifecycle is fully covered: discover candidates, verify single, run bulk, poll status, fetch results, and check credits. Minor gaps like canceling a running bulk job or listing past jobs are workarounds via the dashboard.
Available Tools
6 toolscheck_bulk_statusCheck Bulk Job StatusARead-onlyIdempotentInspect
Check the progress of a bulk verification job started with verify_bulk. Free. Returns status (pending, processing, completed, failed), percent progress, and — once completed — the summary counts (deliverable, undeliverable, risky, unknown, catch-all). Report the summary to the user; when they need the result for each address, call get_bulk_results. The full result file can also be downloaded from the ClearBounce dashboard.
| Name | Required | Description | Default |
|---|---|---|---|
| jobId | Yes | The jobId returned by verify_bulk |
Output Schema
| Name | Required | Description |
|---|---|---|
| jobId | Yes | |
| status | Yes | pending, processing, completed or failed |
| progress | Yes | Percent complete, 0-100 |
| resultsUrl | No | Dashboard page where the full result file can be downloaded |
| riskyCount | No | |
| totalEmails | No | |
| unknownCount | No | |
| catchAllCount | No | |
| processedEmails | No | |
| deliverableCount | No | |
| undeliverableCount | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely new context: the call is free, the status values are enumerated, and progress plus completion-only summary counts are described. The only thing it leaves implicit is whether repeated polling is rate-limited or has eventual-consistency delay.
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?
Front-loaded with the core action and cost, then the return shape, then the routing advice — a logical order with little waste. The enumerated status list is slightly verbose given an output schema exists, but it is cheap and clarifies the returned shape.
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?
Covers the full lifecycle an agent needs: the job is created by verify_bulk, this polls it, statuses and progress are returned, summary counts appear only on completion, and drill-down requires get_bulk_results. With an output schema present, it need not describe return structure further.
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?
One parameter at 100% schema coverage, so the schema already explains jobId; the description merely restates that it comes from verify_bulk. Baseline 3 applies since the description adds no format, constraint, or lifecycle detail beyond the schema.
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?
States a specific verb and resource (check progress of a bulk verification job) and ties it to the originating tool, verify_bulk. The status/progress/summary breakdown makes it immediately distinguishable from siblings like get_bulk_results and check_credits.
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?
Explicitly says when to use this versus the alternative: report summary counts here, but call get_bulk_results when per-address results are needed. It also notes the dashboard download path as an out-of-band option, so the agent has a complete routing picture.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
check_creditsCheck Credit BalanceARead-onlyIdempotentInspect
Return the remaining verification credit balance for the account that owns the API key. Free.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
Output Schema
| Name | Required | Description |
|---|---|---|
| notice | No | Present only when the balance is low or empty |
| credits | Yes | Remaining verification credits on the account |
| success | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context beyond them: the balance is scoped to the API key's owning account, and the call is free (consumes no credits) — an important behavioral fact not encoded in any structured field.
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?
Two short sentences with no waste. The action and scope come first, and the cost note ('Free') trails as a quick value-add.
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 zero-argument read with an output schema and rich annotations, the description supplies everything an agent needs: what it returns, whose balance it is, and that it costs nothing. Return-value shape is already handled by the output schema.
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?
Zero parameters, so there is nothing for the description to disambiguate; baseline of 4 applies. The description sensibly explains that the account is derived from the API key rather than passed as an argument.
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?
States a specific verb and resource ('Return the remaining verification credit balance') plus the account scoping (the account that owns the API key). Among siblings that all perform email verification actions, this is the only balance-read tool, so the distinction is unambiguous.
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 zero-parameter read and the word 'remaining' imply you check this before or after consuming credits in verify_email/verify_bulk, but the description never states when to call it or explicitly points at those siblings. Usage is inferable rather than instructed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
find_emailFind Business Email AddressARead-onlyIdempotentInspect
Find a person's business email address from their full name and company domain. Returns candidate addresses with confidence scores, based on published sources and common company address patterns. Finding is free, but candidates are pattern-based guesses until verified. After showing the candidates, tell the user that confirming deliverability costs 1 credit per candidate checked, and ask before verifying. With approval, call verify_email on candidates one at a time starting from the highest confidence, and stop at the first deliverable result.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Full name of the person, e.g. "Jane Porter" | |
| domain | Yes | Company domain, e.g. "northwindtraders.com" |
Output Schema
| Name | Required | Description |
|---|---|---|
| note | No | Guidance on verification cost and how to proceed |
| status | Yes | found_published when the address came from a published source, otherwise pattern_guesses |
| best_match | No | Highest-confidence candidate address |
| candidates | Yes | Candidate addresses, highest confidence first |
| confidence | No | Confidence of the best match, 0-100 |
| seen_at_company | No | Addresses already published at this domain |
| total_candidates | Yes | |
| detected_company_pattern | No | Address pattern used at this company, when known |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnly and idempotent annotations, the description discloses that candidates are unverified pattern-based guesses, that finding is free while verification costs credits, and that the tool should not verify without user approval. This is substantial behavioral context that the agent would otherwise lack.
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 front-loaded with the core purpose, then efficiently covers return behavior, cost implications, and the required verification workflow. Every sentence delivers essential operational information without padding.
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 tool with two fully documented parameters and an output schema, the description covers purpose, result nature, cost, consent, and the exact follow-up action with verify_email. No critical operational detail is missing 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?
The input schema already fully describes both parameters with examples, so the description's mention of full name and company domain adds limited new meaning. It reinforces the source fields but does not introduce additional parameter-level semantics beyond what the schema provides.
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: find a person's business email from full name and company domain. It clearly differentiates the tool from verify_email by describing find as generating pattern-based candidates rather than confirming deliverability.
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 provides explicit workflow guidance: show candidates, inform the user about credit costs, ask before verifying, then call verify_email one at a time by confidence until a deliverable result is found. This makes the tool's role relative to verify_email and the approval process unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_bulk_resultsGet Bulk Job ResultsARead-onlyIdempotentInspect
Get the per-address results of a completed verify_bulk job: status, sub-status and score for each address. Free — no credits. Use this when the user needs to know which addresses passed or failed; do not re-verify them with verify_email. Optionally filter by status, and page through large jobs with offset (up to 500 results per call).
| Name | Required | Description | Default |
|---|---|---|---|
| jobId | Yes | The jobId returned by verify_bulk | |
| limit | No | Results per call (default 200, max 500) | |
| offset | No | Skip this many results (default 0) | |
| status | No | Only return addresses with this status |
Output Schema
| Name | Required | Description |
|---|---|---|
| note | No | |
| jobId | Yes | |
| total | Yes | Addresses matching the filter |
| offset | No | |
| results | Yes | |
| returned | No | |
| nextOffset | No | Pass as offset to get the next page; null when done |
| statusFilter | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, and non-destructive, so the safety profile is covered; the description adds genuinely new context: the call is free (no credits) and results are capped at 500 per call. It doesn't describe what happens if the job is still running, which is the one behavioral gap.
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 what is returned, followed by routing guidance and pagination options. No filler and each sentence carries distinct information.
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 read-only results tool with a full output schema and 100% parameter documentation, this is complete: it covers the precondition (completed job), cost, routing versus siblings, and paging behavior. Nothing needed to invoke it correctly is missing.
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 baseline is 3, and the description adds usage context beyond the schema: status filtering is optional and offset is the paging mechanism for large jobs. The 'up to 500 results per call' detail slightly repeats the limit field's max, but the paging/filter framing adds real meaning.
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?
A specific verb and resource: retrieves per-address results of a completed verify_bulk job, and names the returned fields (status, sub-status, score). It is clearly separable from verify_bulk (which runs the job) and verify_email (which re-checks a single address).
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?
Explicitly states when to use it ('user needs to know which addresses passed or failed') and when not to ('do not re-verify them with verify_email'), plus the precondition that the job must be completed, which implies check_bulk_status. Nothing is left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
verify_bulkVerify Email List (Bulk)AInspect
Verify a list of email addresses (2 to 10,000) as one bulk job using the full ClearBounce bulk pipeline — per-domain caching and greylist retries give better accuracy than verifying one by one. Costs 1 credit per unique address; duplicates are removed for free. Returns a jobId immediately (the job runs in the background, roughly 1-10 minutes depending on size). Use check_bulk_status with the jobId to get progress and the final summary. Before starting a large list, confirm with the user that spending that many credits is intended.
| Name | Required | Description | Default |
|---|---|---|---|
| emails | Yes | The email addresses to verify (2 to 10,000 items) |
Output Schema
| Name | Required | Description |
|---|---|---|
| note | No | |
| jobId | Yes | Use this with check_bulk_status |
| uniqueEmails | Yes | Addresses queued after duplicate removal — credits charged for these |
| estimatedSeconds | No | Rough time until the job completes |
| duplicatesRemoved | No |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations, the description discloses that the job runs asynchronously in the background, takes roughly 1-10 minutes, costs 1 credit per unique address, deduplicates for free, and returns a jobId rather than immediate results. It also reveals a meaningful side effect (credit consumption) and the need for user confirmation, which annotations alone do not convey.
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 compact but information-dense. Purpose, accuracy benefit, cost model, async behavior, and follow-up action each appear in tight prose, and the most critical facts are front-loaded.
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 tool with one parameter and an output schema, the description covers everything needed to call it correctly: constraints, cost, async return, follow-up status polling, and user-confirmation guidance. It also distinguishes the tool from the sibling verify_email tool without needing further context.
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?
The schema already documents the emails parameter and its 2-to-10,000 item range at 100% coverage, so the baseline is 3. The description adds valuable semantics beyond the schema: duplicates are removed for free and cost is calculated per unique address, so an agent understands the real meaning of the list contents.
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: 'Verify a list of email addresses (2 to 10,000) as one bulk job.' It also differentiates from single-address verification by highlighting the bulk pipeline's per-domain caching and greylist retries, so an agent can see why this tool exists apart from verify_email.
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 explicitly explains when to choose bulk verification over one-by-one verification and names the follow-up tool, check_bulk_status, with the jobId. It also gives a clear behavioral instruction to confirm with the user before spending many credits, which is a strong usage guideline.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
verify_emailVerify Email AddressARead-onlyIdempotentInspect
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.
| Name | Required | Description | Default |
|---|---|---|---|
| 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 |
| 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 |
TDQS
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.
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.
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.
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.
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.
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.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
3 tool updates
- Changed
check_credits1 field changed- removed
Output schema / properties / purchaseUrlRemoved value: -{ - "description": "Where the user can buy more credits", - "type": "string" -}
- Added
get_bulk_results - Changed
verify_email2 fields changed- changed
Output schema / properties / notice / descriptionPrevious 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" - added
Output schema / properties / tipAdded value: +{ + "description": "Present when many single checks arrive in a row: suggests verify_bulk for lists", + "type": "string" +}
2 tool updates
- Changed
check_credits2 fields changed- added
Output schema / properties / noticeAdded value: +{ + "description": "Present only when the balance is low or empty", + "type": "string" +} - added
Output schema / properties / purchaseUrlAdded value: +{ + "description": "Where the user can buy more credits", + "type": "string" +}
- Changed
verify_email1 field changed- added
Output schema / properties / noticeAdded value: +{ + "description": "Present only when the balance is low or empty: tells the user where to buy more credits", + "type": "string" +}
5 tool updates
- First observed
check_bulk_status - First observed
check_credits - First observed
find_email - First observed
verify_bulk - First observed
verify_email
Related MCP Connectors
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Find verified work emails from a name, company, role or LinkedIn URL, and verify emails you have.
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