What can you do with this server?

The RFCXML MCP server provides structured analysis of RFC documents by leveraging their semantic XML structure to extract requirements, analyze dependencies, and generate implementation aids. Core Capabilities: * Extract Normative Requirements - Identify MUST/SHOULD/MAY requirements with condition/exception structuring, filterable by level and section * Retrieve RFC Structure and Metadata - Get section hierarchies, metadata, and optionally include section content * Manage Definitions - Fetch term definitions and their scope, with search capabilities for specific terms * Analyze Dependencies - Map normative and informative references between RFCs, with optional reverse reference lookup * Identify Related Sections - Find sections within an RFC related to a specified section * Generate Implementation Checklists - Create role-based (client/server/both) Markdown checklists, configurable by specific sections * Validate Compliance - Verify if statements or implementation descriptions adhere to RFC requirements Key Features: * Dual Format Support - Uses RFCXML v3 for modern RFCs (8650+) with high accuracy; automatically falls back to text parsing for legacy RFCs with medium accuracy * Source Transparency - All responses indicate data source (XML or text) and accuracy level * Performance Optimized - Parallel fetching from multiple sources with LRU caching for frequently accessed RFCs * BCP 14 Compliant - Recognizes all standard RFC requirement keywords

Which integrations are available for this server?

Supports the generation of structured implementation checklists and protocol documentation in Markdown format for easier display and verification. Provides tools to parse and extract semantic information from RFCXML documents, enabling the retrieval of section hierarchies, normative requirements, and dependency graphs.

RFCXML MCP Server

npm version License: MIT Node.js Claude Code

日本語版 README

A Model Context Protocol (MCP) server for structured understanding of RFC documents.

Purpose

Unlike existing text-based RFC MCP servers, this server leverages the semantic structure of RFCXML to enable:

Normative requirements extraction (MUST/SHOULD/MAY) with structured output
RFC dependency graph construction
Definition scope management
Implementation checklist generation

Architecture

┌─────────────────────────┐ │ Markdown / PDF │ Display & Sharing ├─────────────────────────┤ │ Translation │ Explanation & Verification ├─────────────────────────┤ │ RFCXML MCP │ Common Understanding for AI & Humans ├─────────────────────────┤ │ RFCXML │ Single Source of Truth └─────────────────────────┘

Comparison with Existing MCPs

Feature	Existing mcp-rfc	RFCXML MCP
RFC text retrieval	✅	✅
Section extraction	✅ (text-based)	✅ (structure-based)
MUST/SHOULD/MAY extraction	❌	✅
Condition/exception structuring	❌	✅
RFC dependency graph	❌	✅
Definition scope management	❌	✅
Implementation checklist	❌	✅

Quick Start

Using with Claude Desktop / Claude Code

Add the following to your MCP configuration file:

{ "mcpServers": { "rfcxml": { "command": "npx", "args": ["-y", "@shuji-bonji/rfcxml-mcp"] } } }

Configuration file locations:

Claude Desktop (macOS): ~/Library/Application Support/Claude/claude_desktop_config.json
Claude Desktop (Windows): %APPDATA%\Claude\claude_desktop_config.json
Claude Code: .claude/settings.json or use claude settings command

Installation (Optional)

For global installation:

npm install -g @shuji-bonji/rfcxml-mcp # MCP configuration { "mcpServers": { "rfcxml": { "command": "rfcxml-mcp" } } }

Available Tools

Phase 1: Basic Structure

get_rfc_structure - Get section hierarchy and metadata
get_requirements - Extract normative requirements (MUST/SHOULD/MAY) with structure
get_definitions - Get term definitions and their scope

Phase 2: Relationships

get_rfc_dependencies - Get referenced RFCs (normative/informative)
get_related_sections - Get related sections within the same RFC

Phase 3: Verification Support

validate_statement - Verify if a statement complies with RFC requirements
generate_checklist - Generate implementation checklist

Legacy RFC Support

RFCs published after RFC 8650 (December 2019) are available in official RFCXML v3 format. Earlier RFCs may not have XML available.

This server includes automatic fallback functionality - when XML is unavailable, it parses the text format instead.

Source Information

All responses include source information:

{ "rfc": 6455, "sections": [...], "_source": "text", "_sourceNote": "⚠️ Parsed from text format. Accuracy may be lower." }

`_source`	Description
`xml`	Parsed from RFCXML (high accuracy)
`text`	Parsed from text (medium accuracy)

Compatibility

RFC	Format	Notes
RFC 8650+	XML	Official RFCXML v3 support
Before RFC 8650	Text	Automatic fallback

Output Samples

`get_rfc_structure` - Get RFC Structure

{ "metadata": { "title": "Transmission Control Protocol (TCP)", "docName": "draft-ietf-tcpm-rfc793bis-28", "number": 9293 }, "sections": [ { "number": "section-1", "title": "Purpose and Scope" }, { "number": "section-3", "title": "Functional Specification", "subsections": [ { "number": "section-3.1", "title": "Header Format" }, { "number": "section-3.5", "title": "Establishing a Connection", "subsections": [ { "number": "section-3.5.1", "title": "Half-Open Connections and Other Anomalies" }, { "number": "section-3.5.2", "title": "Reset Generation" } ] } ] } ], "referenceCount": { "normative": 15, "informative": 85 }, "_source": "xml" }

`get_requirements` - Extract Normative Requirements

{ "rfc": 9293, "filter": { "level": "MUST" }, "stats": { "total": 53, "byLevel": { "MUST": 53 } }, "requirements": [ { "id": "R-section-3.5-5", "level": "MUST", "text": "A TCP implementation support simultaneous open attempts (MUST-10).", "section": "section-3.5", "sectionTitle": "Establishing a Connection" }, { "id": "R-section-3.7.1-9", "level": "MUST", "text": "TCP endpoints implement both sending and receiving the MSS Option (MUST-14).", "section": "section-3.7.1", "sectionTitle": "Maximum Segment Size Option" } ], "_source": "xml" }

`get_rfc_dependencies` - Get RFC Dependencies

{ "rfc": 9293, "normative": [ { "rfcNumber": 791, "title": "Internet Protocol", "anchor": "RFC0791" }, { "rfcNumber": 2119, "title": "Key words for use in RFCs to Indicate Requirement Levels" }, { "rfcNumber": 5681, "title": "TCP Congestion Control" } ], "informative": [ { "rfcNumber": 793, "title": "Transmission Control Protocol" }, { "rfcNumber": 1122, "title": "Requirements for Internet Hosts - Communication Layers" } ], "_source": "xml" }

`generate_checklist` - Generate Implementation Checklist

# RFC 9293 Implementation Checklist **Transmission Control Protocol (TCP)** Role: Client ## Required (MUST / REQUIRED / SHALL) - [ ] A TCP implementation support simultaneous open attempts (MUST-10). (section-3.5) - [ ] TCP endpoints implement both sending and receiving the MSS Option (MUST-14). (section-3.7.1) - [ ] The RTO be computed according to the algorithm in, including Karn's algorithm (MUST-18). (section-3.8.1) ## Optional (MAY / OPTIONAL) - [ ] Implementers include "keep-alives" in their TCP implementations (MAY-5). (section-3.8.4)

Text Fallback Output (Legacy RFCs)

{ "metadata": { "title": "The WebSocket Protocol", "number": 6455 }, "sections": [ { "number": "1", "title": "Introduction" }, { "number": "5", "title": "Data Framing" } ], "_source": "text", "_sourceNote": "⚠️ Parsed from text format. Accuracy may be lower." }

Examples

See the examples/ directory for complete checklist samples:

RFC	Protocol	Source
RFC 6455	WebSocket	Text (fallback)
RFC 9293	TCP	RFCXML
RFC 7540	HTTP/2	Text (fallback)

Example prompt for Claude:

Generate an implementation checklist for RFC 9293 (TCP).

Internal Architecture

Module Structure

src/ ├── index.ts # MCP server entry point ├── config.ts # Centralized configuration ├── constants.ts # BCP 14 keyword definitions ├── services/ │ ├── rfc-fetcher.ts # RFC fetching (parallel) │ ├── rfcxml-parser.ts # RFCXML parser │ ├── rfc-text-parser.ts # Text fallback parser │ └── checklist-generator.ts # Checklist generation service ├── tools/ │ ├── definitions.ts # MCP tool definitions │ └── handlers.ts # Tool handlers ├── types/ │ └── index.ts # Type definitions └── utils/ ├── cache.ts # LRU cache ├── fetch.ts # Parallel fetch utility ├── requirement-extractor.ts # Shared requirement extraction ├── section.ts # Section search utilities ├── text.ts # Text processing utility └── validation.ts # Input validation

RFC Fetch Optimization

Sends parallel requests to multiple sources (RFC Editor, IETF Tools, Datatracker) and uses the first successful response:

┌─────────────────┐ │ fetchRFCXML() │ └────────┬────────┘ │ Parallel requests ┌────┴────┬────────────┐ ▼ ▼ ▼ ┌────────┐ ┌────────┐ ┌────────┐ │RFC │ │IETF │ │Data- │ │Editor │ │Tools │ │tracker │ └────┬───┘ └────┬───┘ └────┬───┘ │ │ │ └────┬─────┴──────────┘ │ Promise.any (first success) ▼ ┌───────────┐ │ Successful│ → Cancel other requests via AbortController │ Response │ └───────────┘

Cache Strategy

LRU (Least Recently Used) cache with memory limits:

Cache	Max Entries	Content
XML Cache	20	Raw RFCXML
Text Cache	20	Raw text
Metadata Cache	100	RFC metadata
Parse Cache	50	Parsed structure

Development

# Install dependencies npm install # Development mode npm run dev # Build npm run build # Test npm test # Lint npm run lint # Format npm run format

License

MIT

mjpitz/mcp-rfc - Text-based RFC MCP
ietf-tools/RFCXML - RFCXML schema
xml2rfc - IETF official tool

rfcxml-mcp

RFCXML MCP Server

Purpose

Architecture

Comparison with Existing MCPs

Quick Start

Using with Claude Desktop / Claude Code

Installation (Optional)

Available Tools

Phase 1: Basic Structure

Phase 2: Relationships

Phase 3: Verification Support

Legacy RFC Support

Source Information

Compatibility

Output Samples

`get_rfc_structure` - Get RFC Structure

`get_requirements` - Extract Normative Requirements

`get_rfc_dependencies` - Get RFC Dependencies

`generate_checklist` - Generate Implementation Checklist

Text Fallback Output (Legacy RFCs)

Examples

Internal Architecture

Module Structure

RFC Fetch Optimization

Cache Strategy

Development

License

Resources

Tools

New MCP Servers

Latest Blog Posts

MCP directory API

RFCXML MCP Server

Purpose

Architecture

Comparison with Existing MCPs

Quick Start

Using with Claude Desktop / Claude Code

Installation (Optional)

Available Tools

Phase 1: Basic Structure

Phase 2: Relationships

Phase 3: Verification Support

Legacy RFC Support

Source Information

Compatibility

Output Samples

get_rfc_structure - Get RFC Structure

get_requirements - Extract Normative Requirements

get_rfc_dependencies - Get RFC Dependencies

generate_checklist - Generate Implementation Checklist

Text Fallback Output (Legacy RFCs)

Examples

Internal Architecture

Module Structure

RFC Fetch Optimization

Cache Strategy

Development

License

Related Projects

Resources

Tools

New MCP Servers

Latest Blog Posts

MCP directory API

`get_rfc_structure` - Get RFC Structure

`get_requirements` - Extract Normative Requirements

`get_rfc_dependencies` - Get RFC Dependencies

`generate_checklist` - Generate Implementation Checklist