Koskamo

ClearBounce Email Verification MCP

An official MCP server provided by ClearBounce that allows AI agents to verify single email addresses or entire lists, find business emails, and check account credits. It integrates directly into clients like Claude, ChatGPT, and Cursor to protect sender reputation and improve inbox placement through live mailbox checks.

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

ClearBounce Email Verification MCP logo, by ClearBounceVendor evidenceStreamable HTTPNo sign-inEndpoint checked 2026-11-06Operated by ClearBounce
MCP endpoint (Streamable HTTP)
https://clearbounce.net/mcp
Vendor documentation

What its tools do

6 tools, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.

Read-only (5)

Can change data (1)

6 of 6 have a description · 6 of 6 declare behavior hints · 5 of 5 with parameters document them all

Checks and signals

Each line is separate evidence, not a trust score.

  • Passed Endpoint answered the live check ·
  • Passed Official MCP Registry namespace is tied to clearbounce.net ·
  • Passed Endpoint is on the registry namespace domain ·
  • Availability 1 of 1 checks passed in 30 days

What you can do with it

  • Verify single email addresses in real time
  • Bulk verify email lists for accuracy
  • Find business email addresses
  • Check remaining API credits

Source and maintenance

Vendor evidenceRegistry 1.0.0
mcp-registry: net.clearbounce/email-verification@1.0.0Project website

Protocol and capabilities

Server
clearbounce 2.1.0
MCP protocol negotiated in check
2025-11-25
Tools
6 advertised
Resources
Not advertised
Resource templates
Not advertised
Prompts
Not advertised
Server-advertised capabilities
{
  "tools": {}
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

ClearBounce verifies email addresses in real time. Use verify_email to check whether an address is safe to send to (costs 1 credit), find_email to discover a business email address from a name and company domain (free), and check_credits to see the remaining credit balance. For a LIST of addresses (2 or more), use verify_bulk instead of calling verify_email in a loop: it runs the full bulk pipeline (greylist retries, domain caching) and costs 1 credit per unique address. verify_bulk returns a jobId immediately; poll check_bulk_status for progress and the final summary. Report the summary counts by default. When the user needs the result for each address (which ones failed, or to update their list), call get_bulk_results (free) — never re-verify those addresses with verify_email, which charges again. The full result file can also be downloaded from the dashboard. find_email returns unverified pattern-based candidates: tell the user how many were found, note that verification costs 1 credit per candidate, and only verify with their approval — one candidate at a time from highest confidence, stopping at the first deliverable result. Afterwards, report how many candidates were checked, the credits spent, and the remaining balance (verify_email responses include creditsRemaining). If a tool reports that the account does not have enough credits, tell the user the request was not processed and that credits are managed in their ClearBounce account at clearbounce.net. Do not quote prices or offers. Authenticate by connecting a ClearBounce account (OAuth) or with an API key from https://clearbounce.net/dashboard/api-keys.

Tools

6 advertised

verify_email — Verify Email Address
Advertised by the server during the last successful anonymous check.
Advertised read-onlyOpen-world

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.

verify_email input schema
{
  "type": "object",
  "required": [
    "email"
  ],
  "properties": {
    "email": {
      "type": "string",
      "description": "The email address to verify, e.g. jane@example.com"
    }
  }
}
verify_email output schema
{
  "type": "object",
  "required": [
    "email",
    "status",
    "score",
    "isDeliverable"
  ],
  "properties": {
    "tip": {
      "type": "string",
      "description": "Present when many single checks arrive in a row: suggests verify_bulk for lists"
    },
    "email": {
      "type": "string",
      "description": "The address that was checked"
    },
    "score": {
      "type": "number",
      "description": "Quality score from 0 to 100"
    },
    "checks": {
      "type": "object",
      "description": "Detailed checks: syntax, MX, SMTP, disposable, role, catch-all, typo, risk"
    },
    "notice": {
      "type": "string",
      "description": "Present only when the account balance is low or empty"
    },
    "status": {
      "type": "string",
      "description": "deliverable, undeliverable, risky or unknown"
    },
    "subStatus": {
      "type": "string",
      "description": "Reason code behind the status"
    },
    "isDeliverable": {
      "type": "boolean"
    },
    "creditsRemaining": {
      "type": "number",
      "description": "Credits left on the account after this check"
    }
  }
}
verify_email annotations
{
  "title": "Verify Email Address",
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}
find_email — Find Business Email Address
Advertised by the server during the last successful anonymous check.
Advertised read-onlyOpen-world

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.

find_email input schema
{
  "type": "object",
  "required": [
    "name",
    "domain"
  ],
  "properties": {
    "name": {
      "type": "string",
      "description": "Full name of the person, e.g. \"Jane Porter\""
    },
    "domain": {
      "type": "string",
      "description": "Company domain, e.g. \"northwindtraders.com\""
    }
  }
}
find_email output schema
{
  "type": "object",
  "required": [
    "status",
    "candidates",
    "total_candidates"
  ],
  "properties": {
    "note": {
      "type": "string",
      "description": "Guidance on verification cost and how to proceed"
    },
    "status": {
      "type": "string",
      "description": "found_published when the address came from a published source, otherwise pattern_guesses"
    },
    "best_match": {
      "type": [
        "string",
        "null"
      ],
      "description": "Highest-confidence candidate address"
    },
    "candidates": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "Candidate addresses, highest confidence first"
    },
    "confidence": {
      "type": [
        "number",
        "null"
      ],
      "description": "Confidence of the best match, 0-100"
    },
    "seen_at_company": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "Addresses already published at this domain"
    },
    "total_candidates": {
      "type": "number"
    },
    "detected_company_pattern": {
      "type": [
        "string",
        "null"
      ],
      "description": "Address pattern used at this company, when known"
    }
  }
}
find_email annotations
{
  "title": "Find Business Email Address",
  "readOnlyHint": true,
  "openWorldHint": true,
  "idempotentHint": true,
  "destructiveHint": false
}
verify_bulk — Verify Email List (Bulk)
Advertised by the server during the last successful anonymous check.
Open-world

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.

verify_bulk input schema
{
  "type": "object",
  "required": [
    "emails"
  ],
  "properties": {
    "emails": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "The email addresses to verify (2 to 10,000 items)"
    }
  }
}
verify_bulk output schema
{
  "type": "object",
  "required": [
    "jobId",
    "uniqueEmails"
  ],
  "properties": {
    "note": {
      "type": "string"
    },
    "jobId": {
      "type": "string",
      "description": "Use this with check_bulk_status"
    },
    "uniqueEmails": {
      "type": "number",
      "description": "Addresses queued after duplicate removal — credits charged for these"
    },
    "estimatedSeconds": {
      "type": "number",
      "description": "Rough time until the job completes"
    },
    "duplicatesRemoved": {
      "type": "number"
    }
  }
}
verify_bulk annotations
{
  "title": "Verify Email List (Bulk)",
  "readOnlyHint": false,
  "openWorldHint": true,
  "idempotentHint": false,
  "destructiveHint": false
}
check_bulk_status — Check Bulk Job Status
Advertised by the server during the last successful anonymous check.
Advertised read-only

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.

check_bulk_status input schema
{
  "type": "object",
  "required": [
    "jobId"
  ],
  "properties": {
    "jobId": {
      "type": "string",
      "description": "The jobId returned by verify_bulk"
    }
  }
}
check_bulk_status output schema
{
  "type": "object",
  "required": [
    "jobId",
    "status",
    "progress"
  ],
  "properties": {
    "jobId": {
      "type": "string"
    },
    "status": {
      "type": "string",
      "description": "pending, processing, completed or failed"
    },
    "progress": {
      "type": "number",
      "description": "Percent complete, 0-100"
    },
    "resultsUrl": {
      "type": "string",
      "description": "Dashboard page where the full result file can be downloaded"
    },
    "riskyCount": {
      "type": "number"
    },
    "totalEmails": {
      "type": "number"
    },
    "unknownCount": {
      "type": "number"
    },
    "catchAllCount": {
      "type": "number"
    },
    "processedEmails": {
      "type": "number"
    },
    "deliverableCount": {
      "type": "number"
    },
    "undeliverableCount": {
      "type": "number"
    }
  }
}
check_bulk_status annotations
{
  "title": "Check Bulk Job Status",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}
get_bulk_results — Get Bulk Job Results
Advertised by the server during the last successful anonymous check.
Advertised read-only

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).

get_bulk_results input schema
{
  "type": "object",
  "required": [
    "jobId"
  ],
  "properties": {
    "jobId": {
      "type": "string",
      "description": "The jobId returned by verify_bulk"
    },
    "limit": {
      "type": "number",
      "description": "Results per call (default 200, max 500)"
    },
    "offset": {
      "type": "number",
      "description": "Skip this many results (default 0)"
    },
    "status": {
      "enum": [
        "deliverable",
        "undeliverable",
        "risky",
        "unknown"
      ],
      "type": "string",
      "description": "Only return addresses with this status"
    }
  }
}
get_bulk_results output schema
{
  "type": "object",
  "required": [
    "jobId",
    "total",
    "results"
  ],
  "properties": {
    "note": {
      "type": "string"
    },
    "jobId": {
      "type": "string"
    },
    "total": {
      "type": "number",
      "description": "Addresses matching the filter"
    },
    "offset": {
      "type": "number"
    },
    "results": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "email": {
            "type": "string"
          },
          "score": {
            "type": "number"
          },
          "status": {
            "type": "string"
          },
          "subStatus": {
            "type": [
              "string",
              "null"
            ]
          }
        }
      }
    },
    "returned": {
      "type": "number"
    },
    "nextOffset": {
      "type": [
        "number",
        "null"
      ],
      "description": "Pass as offset to get the next page; null when done"
    },
    "statusFilter": {
      "type": [
        "string",
        "null"
      ]
    }
  }
}
get_bulk_results annotations
{
  "title": "Get Bulk Job Results",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}
check_credits — Check Credit Balance
Advertised by the server during the last successful anonymous check.
Advertised read-only

Return the remaining verification credit balance for the account that owns the API key. Free.

check_credits input schema
{
  "type": "object",
  "properties": {}
}
check_credits output schema
{
  "type": "object",
  "required": [
    "credits"
  ],
  "properties": {
    "notice": {
      "type": "string",
      "description": "Present only when the balance is low or empty"
    },
    "credits": {
      "type": "number",
      "description": "Remaining verification credits on the account"
    },
    "success": {
      "type": "boolean"
    }
  }
}
check_credits annotations
{
  "title": "Check Credit Balance",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

90-day uptime

A lightweight connection check about every six hours, sampled on hosts with many listings. It shows the server answered, not that its tools work.

Too few checks for a percentage yet (1 of 1 answered).

  1. 2026-11-07: 1 of 1 checks answered

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks
1 of 1 (100%)
Average latency
743 ms
95th percentile latency
743 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

  • · probe · passed · 743 ms · metadata changed · 6 tool(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.
Claude Code configuration
claude mcp add --transport http clearbounce-email-verification-mcp https://clearbounce.net/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).
Codex configuration
codex mcp add clearbounce-email-verification-mcp --url https://clearbounce.net/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable clearbounce-email-verification-mcp in your MCP settings.
Cursor configuration
{
  "mcpServers": {
    "clearbounce-email-verification-mcp": {
      "url": "https://clearbounce.net/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).
Cline configuration
{
  "mcpServers": {
    "clearbounce-email-verification-mcp": {
      "type": "streamableHttp",
      "url": "https://clearbounce.net/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start clearbounce-email-verification-mcp and inspect its tools.
VS Code configuration
{
  "servers": {
    "clearbounce-email-verification-mcp": {
      "type": "http",
      "url": "https://clearbounce.net/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.
Gemini CLI configuration
gemini mcp add --transport http clearbounce-email-verification-mcp https://clearbounce.net/mcp

Claude Desktop

Open Claude Settings > Connectors > Add custom connector, enter this server URL and enable it for the conversation. This is a manual remote-connector handoff, not a desktop JSON configuration.
Claude Desktop configuration
https://clearbounce.net/mcp

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.
Windsurf configuration
{
  "mcpServers": {
    "clearbounce-email-verification-mcp": {
      "serverUrl": "https://clearbounce.net/mcp"
    }
  }
}

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