Caido MCP Server

MCP server and CLI for the Caido web proxy. Browse, replay, and analyze HTTP traffic from AI assistants or your terminal. Built on the community Go SDK with 66 tools and 6 read-only resources, OAuth + static token auth, HTTPQL filtering, session cookie jars, batch operations, WebSocket inspection, race condition testing, and full Caido feature coverage.

Source: c0tton-fluff/caido-mcp-server

Architecture

Claude Code  -->  stdio  -->  caido-mcp-server (Go)  -->  GraphQL  -->  Caido (port 8080)
Terminal     -->  caido-cli  -->  same GraphQL API

Both MCP and CLI share internal packages. Uses caido-community/sdk-go for type-safe GraphQL communication.

Install

curl -fsSL https://raw.githubusercontent.com/c0tton-fluff/caido-mcp-server/main/install.sh | bash

Pre-built binaries on Releases (macOS, Linux, Windows - amd64/arm64).

Build from source:

git clone https://github.com/c0tton-fluff/caido-mcp-server.git
cd caido-mcp-server
go build -ldflags "-X main.version=$(git describe --tags)" -o caido-mcp-server ./cmd/mcp

Auth

Option A: Static access token (recommended)

This server talks to the local Caido app’s GraphQL API, which authenticates with the access token from your Caido login session – not a Caido Cloud Personal Access Token. A Cloud PAT (prefixed caido_) is for the cloud/dashboard API and will not work.

Grab the access token from the Caido GUI: open developer tools (CTRL+SHIFT+I) and run in the Console:

JSON.parse(localStorage.CAIDO_AUTHENTICATION).accessToken

Pass it via CAIDO_ACCESS_TOKEN. The older CAIDO_PAT variable is accepted as a deprecated alias.

This token expires after ~7 days. For long-lived setups, use Option B (OAuth auto-refreshes).

Option B: OAuth device flow

CAIDO_URL=http://localhost:8080 caido-mcp-server login

Opens browser, saves token to ~/.caido-mcp/token.json. Auto-refreshes mid-session.

Claude Code Config

{
  "mcpServers": {
    "caido": {
      "command": "caido-mcp-server",
      "args": ["serve"],
      "env": {
        "CAIDO_URL": "http://127.0.0.1:8080",
        "CAIDO_ACCESS_TOKEN": "your-caido-access-token"
      }
    }
  }
}

For authorized engagements where you need real credential values in tool output (to replay captured authenticated requests or produce working curl PoCs), add "CAIDO_ALLOW_SENSITIVE_HEADERS": "true". Without it, sensitive headers (Authorization, Cookie, Set-Cookie, API keys) are replaced with [REDACTED] in all tool output.

MCP Tools (66)

Proxy History & Replay

Replay Sessions & Collections

Automate (Fuzzing)

Findings

Sitemap & Scopes

Projects

Workflows

Tamper Rules (Match & Replace)

Intercept

Environments

Filters

WebSocket

Utilities

Admin

MCP Resources (6)

Read-only data exposed via the MCP resources protocol. Agents can read these without consuming tool calls.

Session Cookie Jar

The server maintains an RFC 6265-compliant in-memory cookie jar per replay session. Any Set-Cookie from a response is stored and auto-injected into subsequent requests targeting the same domain/path.

Key behaviours:

• Pass useCookieJar: false on a single call to disable injection (useful for session-fixation testing or verifying auth gates)
• clear_session_cookies wipes the jar between test runs
• get_session_cookies introspects stored cookies (metadata only, values not returned)
• Each send_request response includes a cookieJar block showing injectedCookies (names sent) and storedCookies (names captured)

Multi-step authenticated flows work out of the box – login once, subsequent requests carry the session automatically.

Built-in Protections

• Credential redaction – Authorization, Cookie, Set-Cookie, Proxy-Authorization, and API key headers replaced with [REDACTED] in all tool output (opt out with CAIDO_ALLOW_SENSITIVE_HEADERS)
• Tool annotations – every tool declares readOnlyHint/destructiveHint/idempotentHint/openWorldHint so MCP clients distinguish read-only, destructive, and external-network tools
• Adaptive body limits – JSON gets 4KB, HTML 3KB, binary 200B (override with explicit bodyLimit)
• Response fingerprinting – auto-detects content kind (json/html/xml/text/binary)
• Response diff – repeated identical responses in the same session collapse to a one-line summary, saving tokens
• Input validation – length limits on all string inputs to prevent context flooding
• Token auto-refresh – expired OAuth tokens refresh mid-session automatically
• Session reuse – single replay session per server lifetime, no sprawl

CLI

Standalone terminal client for Caido. No MCP required.

# Install
curl -fsSL https://raw.githubusercontent.com/c0tton-fluff/caido-mcp-server/main/install.sh | TOOL=cli bash

# Check connection
caido-cli status -u http://localhost:8080

# Send structured requests
caido-cli send GET https://target.com/api/users
caido-cli send POST https://target.com/api/login -j '{"user":"admin","pass":"test"}'
caido-cli send PUT https://target.com/api/profile -H "Authorization: Bearer tok" -j '{"role":"admin"}'

# Send raw HTTP
caido-cli raw 'GET /api/users HTTP/1.1\r\nHost: target.com\r\n\r\n'
caido-cli raw -f request.txt --host target.com --port 8443

# Parallel requests (BAC sweeps, param fuzzing, endpoint sweeps)
caido-cli batch sweep https://target.com/api/profile -t "owner=eyJ1...,cross=eyJ2...,noauth=eyJ3"
caido-cli batch fuzz "https://target.com/api/search?q=test" -p q -v "test,test',1 OR 1=1"
caido-cli batch ep -t eyJ... https://target.com/dashboard https://target.com/admin

# Browse proxy history
caido-cli history
caido-cli history -f 'req.host.eq:"target.com"' -n 20

# Get full request/response
caido-cli request 12345

# Encode/decode
caido-cli encode base64 "hello world"
caido-cli decode url "%3Cscript%3E"

Caido vs Burp MCP

Use Caido for: daily proxy work, HTTPQL filtering, multi-step authenticated flows, fuzzing with Automate, workflow automation, batch testing, intercept control, WebSocket inspection, race condition testing.

Use Burp for: active scanning, Collaborator/blind testing, extension ecosystem (Autorize, Param Miner).

Port Notes

• Caido default proxy: 127.0.0.1:8080
• Burp default proxy: 127.0.0.1:8080 (conflict)
• Change one (e.g., Caido to 127.0.0.1:1234)
• MCP servers use different ports: Caido GraphQL (8080) vs Burp SSE (9876) – no conflict

Related

• 2026-07-17 Burp MCP Server
• 2026-07-17 HackerOne MCP Server
• 2026-07-17 SentinelOne MCP Server
• 2026-07-17 Caido Go SDK