enrichment-mcp: Depth-First Lead Discovery for a Bug-Bounty Offering

Project Overview

Selling a penetration-testing / bug-bounty service is a high-consideration, low-volume sale. Spraying hundreds of generic emails is the wrong shape for it -- the win is a few right companies, each reached through the right person, not a big funnel of weak contacts. Most lead-gen tooling optimises for the opposite: discover everything, enrich everything, auto-send. That produces volume and burns goodwill.

enrichment-mcp inverts that. It is a depth-first lead finder: per run it surfaces a handful of candidate webshops, qualifies them hard, and for each keeper resolves the single best decision-maker. The deliverable stops at a stored, qualified lead carrying lean context -- enough to recognise the company, one verified contact, and a one-line "why". A human decides what to do next; the system never reaches out and never tests anything.

The design splits cleanly across two execution contexts. Claude (in claude.ai or Claude Code) runs discovery and qualification in-session using its own web_search / web_fetch -- no third-party search API, no LLM key pool. A thin FastMCP server does only the two things the chat sandbox cannot: paid contact resolution through Prospeo (an outbound API the sandbox blocks) and a durable lead store that remembers state across sessions. This is a ground-up rebuild of an older volume-funnel pipeline (clay-enrichment); roughly 5,000 lines of key-pool and worker machinery were dropped, four assets salvaged.

Related MCP server: LeadsClean MCP Server

How It Works

For each run, Claude drives the loop and calls the server only when it must:

  Claude session  (lead-finder skill)
    web_search / web_fetch  ── discovery, hard qualification, NO_MATCH fallback mining
        │  tool calls over HTTPS (static bearer)
        ▼
  https://enrichment-mcp-<num>.<region>.run.app/mcp     (Cloud Run — auto-HTTPS, scales to zero)
        │
  Cloud Run container (GCP) — env from Secret Manager
    FastMCP server  ── 7 tools, bearer auth, Streamable HTTP at /mcp
        │
        ▼
  Supabase Postgres            Prospeo enrich-person        MyEmailVerifier
  (leads + prospeo_usage)      (X-KEY multi-key pool)       (validate_single)

The qualification loop is deliberately discard-heavy:

1. Discover -- run one to three angles via web_search to surface a handful of candidates (not a funnel).

2. Qualify hard -- web_fetch each site and score it 0-10 against the ICP: is it a custom (non-platform) webshop, is it receptive (no existing public bounty program), is there a reachable technical decision-maker, can it plausibly pay.

3. Keep only winners -- discard anything under the >=7 gate immediately and explicitly. Quality over count.

4. Resolve one contact -- name the single best decision-maker, then call resolve_contact; the server runs the Prospeo pool and returns one verified email + LinkedIn + title.

5. Fallback on miss -- on Prospeo NO_MATCH, mine the site's team/about pages in-session, guess the email pattern, and confirm with verify_email; accept only a Valid result.

6. Store lean -- write the lead via add_qualified_lead. If no contact resolves, the company is still stored (flagged), never thrown away.

Data-flow invariant: web tools run in the session; Prospeo and state run on the server. The server holds no loop, no scheduler, no autonomous discovery -- it only acts when Claude calls a tool.

Targeting Scope

The qualification rubric scores five criteria 0-2 each (custom-stack confidence, receptiveness, attack surface, ability to pay, reachable decision-maker) and sums to a 0-10 bounty_fit_score. The keep-gate is >=7 and custom-stack >=1 and receptiveness >=1, so a clear platform store or an existing bounty program is an automatic discard regardless of total.

Quick Start

Requirements: Python 3.10+ and a Postgres instance (the design targets Supabase; any Postgres works).

# 1. Create a virtualenv and install dependencies
python3 -m venv .venv
.venv/bin/pip install -r requirements.txt

# 2. Configure environment
cp .env.example .env
# Edit .env and fill in the values (see the table below)

# 3. Apply the database schema (SUPABASE_DB_URL must be set)
psql "$SUPABASE_DB_URL" -f schema/001_leads.sql

# 4. Run the server
.venv/bin/python -m src.mcp_server
# Serves Streamable HTTP at http://MCP_HOST:MCP_PORT/mcp (default 0.0.0.0:8000)

Environment variables (.env.example is the authoritative list):

Usage

Connecting Claude

Claude Code (default path -- static bearer):

claude mcp add --transport http enrichment-mcp \
  https://enrichment-mcp-<num>.<region>.run.app/mcp \
  --header "Authorization: Bearer <MCP_BEARER_TOKEN>"

Use the live Cloud Run service URL (printed by the deploy) with /mcp appended, and the MCP_BEARER_TOKEN from Secret Manager.

claude.ai web connector (OAuth). The web app cannot send a bearer header, so it uses OAuth. The server supports it via MCP_OAUTH_PROVIDER (see auth.py):

• workos (recommended) -- WorkOS AuthKit via the full WorkOSProvider: FastMCP serves the OAuth + DCR endpoints to claude.ai itself and proxies the login to AuthKit with a pre-registered client (so it works even though AuthKit's metadata omits a registration endpoint). Set MCP_OAUTH_PROVIDER=workos, WORKOS_AUTHKIT_DOMAIN=https://<name>.authkit.app, WORKOS_CLIENT_ID, WORKOS_CLIENT_SECRET (the WorkOS API key), and MCP_BASE_URL=<public run.app URL>, then redeploy. Add <MCP_BASE_URL>/auth/callback to the WorkOS application's redirect URIs. claude.ai (Settings -> Connectors -> Add custom connector -> paste <base>/mcp) then drives the login.

• oidc -- any OIDC provider (Descope, Auth0, Google, ...) via OIDCProxy: set MCP_OIDC_CONFIG_URL, MCP_OIDC_CLIENT_ID (+ secret), and MCP_BASE_URL.

• supabase -- reuse the project's own Supabase Auth, but only if that project advertises an OAuth registration endpoint (many do not -- prefer workos).

Switching modes is pure config -- no code change. Bearer mode (empty MCP_OAUTH_PROVIDER) stays available for Claude Code.

Running a lead hunt

The skills/lead-finder/ skill drives the depth-first workflow end-to-end. In a Claude session with the connector attached, give it a brief ("independent EU streetwear shops on custom stacks") and it runs discovery, qualifies, resolves contacts, and stores keepers -- calling the tools below. Across sessions, get_uncontacted is the durable memory of who is qualified but not yet acted on.

Tools

Lead store (CRM / state)

Contact resolution (server-side network)

Status flow: qualified --> contact_resolved --> contacted --> replied --> closed / rejected.

Technical Details

Module breakdown

The lead record (intentionally lean)

One leads table, keyed on domain:

A second table, prospeo_usage, meters credit burn across the key pool.

Credit model

Depth-first targeting keeps these low by design -- one resolution per kept lead, not per candidate.

Hosting

The server runs on Google Cloud Run as a container: automatic HTTPS, a public *.run.app URL, and scale-to-zero (no cost when idle). Secrets live in Secret Manager and are injected as env vars; the app-layer bearer is what actually protects the public endpoint (--allow-unauthenticated at the IAM layer so claude.ai, which carries no Google identity, can reach it).

deploy/deploy-cloudrun.sh is the reproducible runbook (project, APIs, secrets, deploy). The Dockerfile builds the image; Cloud Run injects $PORT, which config.py honors. One-liner to redeploy after a code change:

gcloud run deploy enrichment-mcp --source . --region <region> \
  --allow-unauthenticated --max-instances 1 \
  --set-secrets=MCP_BEARER_TOKEN=MCP_BEARER_TOKEN:latest,SUPABASE_DB_URL=SUPABASE_DB_URL:latest,PROSPEO_API_KEYS=PROSPEO_API_KEYS:latest,MYEMAILVERIFIER_API_KEY=MYEMAILVERIFIER_API_KEY:latest

Cloud Run pins secret versions per revision, so after updating a secret value, redeploy (or roll a new revision) to pick it up.

Roadmap

• Platform fingerprint tool -- an optional server-side check (cdn.shopify.com, /wp-content/, platform headers) if Claude's page-judgment of custom-vs-platform proves unreliable. Deliberately deferred; Claude judges from the page for now.

• OAuth path for the claude.ai web connector -- FastMCP OIDCProxy + a hosted IdP, swappable into the existing auth layer.

• domain-search assist -- fall back to Prospeo's domain search when naming the decision-maker is hard (currently out of scope to preserve the one-best principle).

Disclaimer

This is a sales-qualification tool, not a reconnaissance or testing tool. It discovers publicly listed companies, judges their fit for a security-research engagement, and identifies one business contact for a human to approach. It does not contact prospects, does not send email, and does not run or trigger any security test -- those remain separate, human-gated actions. Process contact data in line with GDPR and applicable anti-spam rules, and only pursue testing against a target with explicit written authorization. Built for the author's own bug-bounty offering; not licensed for external distribution.