dcert 3.0.21

MCP server for TLS certificate analysis via the Model Context Protocol

dcert (Python)

A Python MCP wrapper for the dcert Rust server.

Uses FastMCP to create a transparent proxy around the dcert-mcp Rust binary, exposing all TLS certificate tools via the Model Context Protocol. New tools added to the Rust binary are automatically available without any Python code changes.

Requirements

• Python 3.12+
• The dcert-mcp Rust binary is bundled in platform-specific wheels (no network access needed at runtime)

Installation

pip install dcert

Platform-specific wheels are available for:

• Linux x86_64 (Ubuntu 22.04+, glibc 2.35+)
• macOS Intel (x86_64)
• macOS Apple Silicon (ARM64)

A universal fallback wheel auto-downloads the binary on first use if no platform wheel matches.

Quick Start

As a server

from dcert import create_server

server = create_server()
server.run()  # stdio mode (default)

As a client

import asyncio
from dcert import create_client

async def main():
    async with create_client() as client:
        tools = await client.list_tools()
        print(f"Available tools: {len(tools)}")

        result = await client.call_tool(
            "analyze_certificate", {"target": "example.com"}
        )
        print(result)

asyncio.run(main())

Typed async tool wrappers

For production use with type safety, timeouts, and automatic reconnection:

import asyncio
from dcert.tools import DcertClient

async def main():
    async with DcertClient(timeout=60.0) as dcert:
        # Analyze a certificate
        result = await dcert.analyze_certificate(target="example.com")

        # Check expiry with custom threshold
        expiry = await dcert.check_expiry(target="example.com", days=90)

        # Get TLS connection details
        info = await dcert.tls_connection_info(target="example.com")

        # Export PEM chain
        pem = await dcert.export_pem(target="example.com", output_path="chain.pem")

asyncio.run(main())

All 11 tools are available as typed async methods:

Method	Description
analyze_certificate()	Decode and analyze TLS certificates
check_expiry()	Check certificate expiry within N days
check_revocation()	Check OCSP revocation status
compare_certificates()	Compare certificates between two targets
tls_connection_info()	Get TLS connection details (cipher, protocol, latency)
export_pem()	Export certificate chain as PEM
verify_key_match()	Verify private key matches a certificate
convert_pfx_to_pem()	Convert PKCS12/PFX to PEM files
convert_pem_to_pfx()	Convert PEM cert+key to PKCS12/PFX
create_keystore()	Create PKCS12 keystore (Java-compatible)
create_truststore()	Create PKCS12 truststore from CA certs

Error handling

from dcert.tools import (
    DcertClient,
    DcertError,          # Base exception
    DcertTimeoutError,   # Tool call timed out
    DcertConnectionError,# Subprocess died
    DcertToolError,      # MCP tool returned an error
)

async with DcertClient(timeout=30.0, max_reconnects=3) as dcert:
    try:
        result = await dcert.analyze_certificate(target="example.com")
    except DcertTimeoutError:
        print("Tool call timed out")
    except DcertToolError as e:
        print(f"Tool error: {e} (tool={e.tool})")
    except DcertConnectionError:
        print("Binary subprocess crashed")

CLI

# stdio mode (default, for MCP clients like Claude Code)
dcert-python

# HTTP mode
dcert-python --transport http --host 0.0.0.0 --port 8080

# Pre-download binary (universal wheel only)
dcert-python --setup

# Explicit binary path
dcert-python --binary /usr/local/bin/dcert-mcp

Binary Discovery

The package locates the dcert-mcp Rust binary in this order:

1. DCERT_MCP_BINARY environment variable
2. Bundled binary in the package bin/ directory
3. dcert-mcp on PATH (platform wheels install the binary here)
4. Auto-download from GitHub Releases (universal wheel fallback, with SHA256 verification)

Environment Variables

The proxy forwards these environment variables to the Rust binary:

Category	Variables
Proxy	HTTP_PROXY, HTTPS_PROXY, NO_PROXY (and lowercase variants)
TLS	SSL_CERT_FILE, SSL_CERT_DIR
dcert	DCERT_PATH, DCERT_MCP_TIMEOUT, DCERT_MCP_CONNECTION_TIMEOUT, DCERT_MCP_READ_TIMEOUT

Scalability

This package uses the MCP proxy pattern: the Python layer never needs to know about individual dcert tools. All tool discovery, input schemas, and invocations are forwarded to the Rust binary via the MCP protocol at runtime. When new capabilities are added to the Rust server, they are immediately available through the Python wrapper.

License

MIT