MCPLint

Security testing tool for Model Context Protocol (MCP) servers.

Features

Protocol validation - verify MCP compliance
Security scanning - detect vulnerabilities
Coverage-guided fuzzing - find crashes and edge cases
Tool fingerprinting - detect schema changes and breaking API updates
AI-powered explanations - understand findings with remediation guidance
CI/CD integration - SARIF, JUnit, GitLab output formats
Config file support - reads Claude Desktop config to find servers

Installation

cargo install --path .

Or build from source:

cargo build --release

./target/release/mcplint --help

Usage

# List servers from Claude Desktop config

mcplint servers


# Validate a server

mcplint validate <server>
mcplint validate filesystem

mcplint validate                    # validates all servers from config


# Security scan

mcplint scan <server>

# Fuzz a server

mcplint fuzz <server>

# AI-powered explanations

mcplint explain <server>

# Watch mode

mcplint watch <server>

# List security rules

mcplint rules

mcplint rules --details


# Environment check

mcplint doctor


# Cache management

mcplint cache stats

mcplint cache clear


# Tool fingerprinting

mcplint fingerprint generate <server>
mcplint fingerprint compare <server> --baseline baseline.json


# Generate config

mcplint init

Commands

validate

Check MCP server for protocol compliance. Runs 56 validation rules across protocol, schema, sequence, tool, resource, security, and edge case categories.

mcplint validate <server> [options]


Options:

  -t, --timeout <seconds>    Timeout for server operations [default: 30]

  -f, --format <format>      Output format: text, json, sarif, junit, gitlab

  -c, --config <path>        Path to MCP config file

scan

Scan for security vulnerabilities.

mcplint scan <server> [options]


Options:

  -p, --profile <profile>    Scan profile: quick, standard, full, enterprise

  -i, --include <rules>      Include specific rule categories

  -e, --exclude <rules>      Exclude specific rule categories

  -t, --timeout <seconds>    Timeout [default: 60]

  --baseline <path>          Compare against baseline file

  --save-baseline <path>     Save results as baseline

  --fail-on <severities>     Fail only on specified severities

fuzz

Coverage-guided fuzzing.

mcplint fuzz <server> [options]


Options:

  -d, --duration <seconds>   Duration to run [default: 300]

  -c, --corpus <path>        Corpus directory

  -W, --workers <count>      Parallel workers [default: 4]

  --max-memory <size>        Memory limit (e.g., 512MB)
  --max-time <time>          Time limit (e.g., 5m)

explain

AI-powered explanations for security findings.

mcplint explain <server> [options]


Options:

  -P, --provider <provider>  AI provider: ollama, anthropic, openai [default: ollama]

  -m, --model <model>        Model to use

  -a, --audience <level>     Audience: beginner, intermediate, expert

  -n, --max-findings <n>     Max findings to explain

AI providers require environment variables:

Anthropic: ANTHROPIC_API_KEY
OpenAI: OPENAI_API_KEY
Ollama: runs locally, no key needed

fingerprint

Generate and compare tool definition fingerprints to detect schema changes.

# Generate fingerprints

mcplint fingerprint generate <server> [options]


Options:

  -o, --output <path>        Save fingerprints to file

  -t, --timeout <seconds>    Timeout [default: 30]

  -f, --format <format>      Output format: text, json


# Compare against baseline

mcplint fingerprint compare <server> --baseline <path> [options]


Options:

  -b, --baseline <path>      Baseline file for comparison (required)
  -t, --timeout <seconds>    Timeout [default: 30]

Exit codes for compare:

0: No changes or minor/patch changes
1: Breaking changes detected
2: Major changes detected

See docs/fingerprinting.md for detailed documentation.

servers

List MCP servers from Claude Desktop config.

mcplint servers

cache

Manage cache storage.

mcplint cache stats          # show statistics

mcplint cache clear          # clear all entries

mcplint cache prune          # remove expired entries

mcplint cache keys           # list cache keys

mcplint cache export -o f    # export to file

mcplint cache import -i f    # import from file

Validation Rules

56 rules across 7 categories:

Category	Rules	Description
Protocol	PROTO-001 to PROTO-015	JSON-RPC 2.0 compliance, MCP version
Schema	SCHEMA-001 to SCHEMA-005	JSON Schema validation
Sequence	SEQ-001 to SEQ-003	Method call sequences
Tool	TOOL-001 to TOOL-005	Tool invocation
Resource	RES-001 to RES-003	Resource listing and reading
Security	SEC-001 to SEC-015	Path traversal, injection, SSRF, XXE, template injection, prompt injection, tool shadowing
Edge	EDGE-001 to EDGE-010	Null bytes, deep nesting, overflow, timeouts

Run mcplint rules --details to see all rules.

Security Rules (Scanner)

20+ rules for vulnerability detection:

Category	Description
injection	Command injection, SQL injection, path traversal, SSRF
auth	Authentication, credential exposure, OAuth scope abuse
transport	TLS/SSL security
protocol	Tool poisoning, shadowing, rug pull detection
data	Data exposure
dos	Denial of service

Output Formats

Format	Flag	Use
text	--format text	Terminal output (default)
json	--format json	Machine-parseable
sarif	--format sarif	GitHub Code Scanning
junit	--format junit	Test runners
gitlab	--format gitlab	GitLab Code Quality

Configuration

Create .mcplint.toml:

mcplint init

Example:

[scan]

profile = "standard"

exclude = ["MCP-DOS-002"]

fail_on = ["critical", "high"]



[fuzz]

duration = 600

workers = 8



[ai]

provider = "ollama"

model = "llama3.2"

Exit Codes

Code	Meaning
0	Success, no findings
1	Success, findings detected
2	Error
3	Partial success
4	Timeout

License

MIT

mcplint 0.2.0