BountyProof MCP

BountyProof is a small MCP server for authorized bug bounty work. It keeps the workflow explicit and evidence-driven:

session (scope + rules) -> preflight -> surface discovery/import -> targeted checks -> verification -> evidence

WAF detection is not treated as a vulnerability. It is part of the preflight check, where BountyProof decides whether live testing is practical or likely to be wasted on challenges, rate limits, unstable responses, off-host redirects, or other edge protection.

Responsible use

BountyProof is provided for educational purposes and authorized security testing only. Use it only on systems you own or targets for which you have explicit permission to test.

You are responsible for following the applicable law, the bug bounty program's scope, and its testing rules. The built-in scope and authorization checks are safeguards, not a substitute for permission. The authors and contributors are not responsible for misuse, unauthorized testing, damage, or legal consequences resulting from the use of this software.

Related MCP server: recon-mcp

What it uses

BountyProof has a built-in HTTP client and relies on only two external binaries:

• Katana for URL discovery, restricted to hosts that passed preflight.

• Nuclei for high- and critical-severity HTTP templates. Fuzzing, DoS, brute force, and headless templates are excluded.

There is no generic shell tool, custom payload runner, mass scanner, subdomain brute force, credential attack, or automatic exploitation.

MCP tools

1. start_session(...) records the program, scope, exclusions, rules, allowed activities, restrictions, rate limit, and authorization. It does not send network traffic.

2. scope_check(session_id, url) checks a URL against the session scope without sending a request.

3. preflight_target(session_id, url) classifies a target as clear, guarded, or blocked.

4. discover_surface(...) runs Katana after a successful preflight.

5. scan_high_signal(...) runs a tightly rate-limited Nuclei scan using high- or critical-severity HTTP templates.

6. verify_finding(...) repeats one matched template two or three times.

7. find_origin_candidates(...) looks for possible origin IPs through in-scope DNS hints and, when configured, historical A records.

8. verify_origin_candidate(...) compares one edge response with one direct-IP HTTPS response after fresh user approval.

9. import_surface(...) imports HAR, OpenAPI, or Postman data with scope filtering and value redaction.

10. register_auth_profiles(...) stores roles and environment variable names, never credential values.

11. compare_authorization(...) compares the same GET request as the owner and another identity for two or three rounds.

12. get_report(...) returns a sanitized JSON or Markdown report.

Every tool except start_session requires a session_id. Exclusions take priority over inclusions, including URL path prefixes. An activity is rejected unless it appears in the session's allowed_activities list:

preflight
discovery
nuclei-scan
verification
origin-discovery
origin-verification
surface-import
authorization-testing

Live discovery, scanning, and authorization comparison also require a preflight_run_id. The scheme, host, and port must match the preflight target. A blocked result cannot be overridden. A guarded result requires a manual review and override_guarded=true.

Preflight results

Cloudflare, Akamai, Imperva, CloudFront, F5, Sucuri, Fastly, and Azure edge indicators are recorded only as preflight metadata. They are never reported as vulnerabilities.

Installation

BountyProof is developed and documented primarily for Linux. Windows can be used as an optional client environment, but the Linux setup is the reference configuration.

Linux (recommended)

Requirements:

• Python 3.11 or newer

• Git

• Katana available in PATH

• Nuclei and nuclei-templates available in PATH

On Debian or Ubuntu, install the base packages first:

sudo apt update
sudo apt install -y git python3 python3-pip python3-venv

Clone and install BountyProof:

git clone https://github.com/skyxtools/bountyproof-mcp.git
cd bountyproof-mcp
python3 -m venv .venv
source .venv/bin/activate
python -m pip install -e .

Set the runtime environment and start the MCP server:

export BOUNTYPROOF_WORKSPACE="$(pwd)"
export BOUNTYPROOF_ALLOWED_PORTS="443"
export BOUNTYPROOF_CONTACT="researcher@example.com"
bountyproof-mcp

If Katana or Nuclei is not in PATH, set the executable paths explicitly:

export BOUNTYPROOF_KATANA_BIN="$HOME/go/bin/katana"
export BOUNTYPROOF_NUCLEI_BIN="$HOME/go/bin/nuclei"

Confirm that both tools are available before starting OpenCode:

"$BOUNTYPROOF_KATANA_BIN" -version
"$BOUNTYPROOF_NUCLEI_BIN" -version

Windows (optional)

Windows is not the primary environment, but the MCP server can still be installed with PowerShell:

git clone https://github.com/skyxtools/bountyproof-mcp.git
cd bountyproof-mcp
py -3.11 -m venv .venv
.\.venv\Scripts\Activate.ps1
python -m pip install -e .

$env:BOUNTYPROOF_WORKSPACE = (Get-Location).Path
$env:BOUNTYPROOF_ALLOWED_PORTS = "443"
$env:BOUNTYPROOF_CONTACT = "researcher@example.com"
bountyproof-mcp

If the external tools are not in PATH:

$env:BOUNTYPROOF_KATANA_BIN = "C:\Tools\katana.exe"
$env:BOUNTYPROOF_NUCLEI_BIN = "C:\Tools\nuclei.exe"

OpenCode setup

Copy opencode.jsonc.example to opencode.jsonc in your OpenCode project and update the Linux executable path to the absolute path of .venv/bin/bountyproof-mcp. Set BOUNTYPROOF_WORKSPACE and any credential environment variables in the shell before starting OpenCode. OpenCode expands {env:VARIABLE} and passes the value to the MCP process through its environment option, so secrets do not need to be written into the config file.

Copy .opencode/commands/bounty-start.md into the project where OpenCode runs, or place it at ~/.config/opencode/commands/bounty-start.md to make it available globally. Start each engagement with:

/bounty-start

The command asks for the program name, in-scope assets, exclusions, rules, allowed activities, restrictions, rate limit, and confirmation that the test is authorized. Once you approve the summary, OpenCode calls bountyproof_start_session and returns a session_id.

An MCP server cannot open a dialog simply because its process has started. The client must initiate the interaction, which is why the custom command is the entry point.

For MCP clients other than OpenCode:

{
  "mcpServers": {
    "bountyproof": {
      "command": "/absolute/path/to/.venv/bin/bountyproof-mcp",
      "args": [],
      "env": {
        "BOUNTYPROOF_ALLOWED_PORTS": "443",
        "BOUNTYPROOF_CONTACT": "researcher@example.com"
      }
    }
  }
}

For the optional Windows setup, replace the command with the absolute path to .venv\\Scripts\\bountyproof-mcp.exe.

Workflow

1. Start a session

Run /bounty-start in OpenCode. Supported scope formats include:

• Exact host: api.example.com

• Wildcard subdomain: *.example.com

• URL and path prefix: https://app.example.com/api/

Out-of-scope entries always win. For example, an in-scope entry of https://app.example.com/api/ combined with an exclusion of https://app.example.com/api/admin/ blocks the entire admin path.

2. Run preflight

scope_check(session_id="session-...", url="https://app.example.com/")
preflight_target(session_id="session-...", url="https://app.example.com/", samples=3)

Preflight sends between two and five GET requests to the same URL. It does not send attack payloads.

3. Discover the surface

discover_surface(
  session_id="session-...",
  url="https://app.example.com/",
  preflight_run_id="preflight-...",
  depth=2
)

Katana is restricted to fqdn scope, concurrency 1, and the session rate limit, with a hard maximum of two requests per second.

4. Run a high-signal scan

scan_high_signal(
  session_id="session-...",
  urls=["https://app.example.com/api"],
  preflight_run_id="preflight-...",
  profile="high-signal"
)

The high-signal profile includes only high and critical findings. The critical-only profile is narrower. A Nuclei match remains a candidate until it has been verified.

5. Verify a candidate

verify_finding(
  session_id="session-...",
  scan_run_id="scan-...",
  finding_index=0,
  rounds=2
)

repeatable-candidate means that the same template matched on every verification round. Business impact and program-policy compliance still require manual review.

6. Check a possible origin

find_origin_candidates uses two sources:

• DNS resolution for hostnames labeled origin, direct, backend, server, dev, or staging. A hostname is queried only when it matches the wildcard scope and is not excluded.

• Historical A records from SecurityTrails when BOUNTYPROOF_SECURITYTRAILS_API_KEY is configured.

Every result starts as an unverified-origin-candidate. Do not send it directly to a scanner.

find_origin_candidates(
  session_id="session-...",
  target_url="https://app.example.com/",
  preflight_run_id="preflight-..."
)

If origin-verification is allowed by the program rules, review the candidate IP and confirm a direct request separately. The verification tool then sends exactly two requests: one to the edge and one to the candidate IP, using the target's TLS SNI and HTTP Host header.

verify_origin_candidate(
  session_id="session-...",
  origin_run_id="origin-...",
  candidate_index=0,
  direct_request_confirmed=true
)

The workflow stops after this comparison. Review the evidence, check the IP owner and hosting provider, and confirm whether the raw IP is covered by the program scope. BountyProof will not pass the IP to scan_high_signal. Any further testing requires a separate decision.

7. Import a surface and compare authorization

Surfaces can be imported from HAR, OpenAPI JSON/YAML, or a Postman Collection. The file must be inside BOUNTYPROOF_IMPORT_ROOT. Header values and request bodies are not stored; only header names, parameter names, and body field names are retained. Out-of-scope endpoints are discarded.

Full replay URLs remain in the local, gitignored report. MCP output masks query values and path segments that look like object identifiers.

import_surface(
  session_id="session-...",
  file_path="captures/app.har",
  input_format="auto"
)

Do not send credentials through chat or MCP parameters. Put tokens or cookies in environment variables available to the MCP process, then register references to those variables:

export BOUNTY_USER_A_TOKEN="<SET_OUTSIDE_CHAT>"
export BOUNTY_USER_B_TOKEN="<SET_OUTSIDE_CHAT>"

On optional Windows clients, set the same variables with $env:BOUNTY_USER_A_TOKEN and $env:BOUNTY_USER_B_TOKEN in PowerShell.

register_auth_profiles(
  session_id="session-...",
  profiles=[
    {"name":"user_a", "role":"owner", "auth_type":"bearer", "credential_env":"BOUNTY_USER_A_TOKEN"},
    {"name":"user_b", "role":"other-user", "auth_type":"bearer", "credential_env":"BOUNTY_USER_B_TOKEN"},
    {"name":"anonymous", "role":"anonymous", "auth_type":"anonymous"}
  ]
)

compare_authorization accepts only replayable GET endpoints. It does not change the object ID, parameters, method, or body. The owner and comparison profiles are requested two or three times. A candidate is created only when the comparison profile consistently receives a 2xx response whose body is identical to the owner's response or whose canonical JSON is stable and equal.

compare_authorization(
  session_id="session-...",
  surface_run_id="surface-...",
  endpoint_index=0,
  preflight_run_id="preflight-...",
  owner_profile="user_a",
  comparison_profiles=["user_b", "anonymous"],
  expected_policy="owner-only",
  rounds=2
)

The workflow stops when a differential candidate is found. BountyProof does not enumerate or replace object IDs automatically. Before any additional impact testing, confirm that the comparison identity should not have access to the object.

Evidence and privacy

Sessions are stored in .bountyproof/sessions/, authentication profile metadata in .bountyproof/auth-profiles/, and reports in .bountyproof/reports/. All three paths are excluded from Git.

Authentication profiles contain environment variable names, not their values. Raw Nuclei request and response data stays local and is not returned through MCP. Nuclei is instructed to redact authorization, cookie, and set-cookie fields.

Configuration

Tests

python -m unittest discover -s tests -v

The unit tests do not contact external targets.

License

MIT. The project was inspired by HexStrike AI's MCP orchestration concept, but the implementation is independent and deliberately limited to a small workflow with strict guardrails.