RLM MCP Server

Recursive Language Model patterns for Claude Code — handle massive contexts (10M+ tokens) by treating them as external variables.

Based on: https://arxiv.org/html/2512.24601v1

How Users Interact

You don't call RLM tools directly. You ask Claude to analyze large files, and Claude uses RLM behind the scenes.

Example:

• You say: "Analyze this 2MB log file for errors"
• Claude uses RLM tools internally
• You get: "I found 3 error patterns: database timeouts (47), auth failures (23)..."

Core Idea

Instead of feeding massive contexts directly into the LLM:

1. Load context as external variable (stays out of prompt)
2. Inspect structure programmatically
3. Chunk strategically (lines, chars, or paragraphs)
4. Sub-query recursively on chunks
5. Aggregate results for final synthesis

Quick Start

Installation

git clone https://github.com/richardwhiteii/rlm.git
cd rlm
uv sync

Or with pip:

python -m venv .venv
source .venv/bin/activate
pip install -e .

Configure for Claude Code

Option 1: Quick Setup (recommended)

# From the rlm directory
claude mcp add rlm -s user -- uv run --directory "$(pwd)" python -m src.rlm_mcp_server

This adds RLM globally (-s user) so it's available in all your Claude Code sessions.

Option 2: With Ollama (free local inference)

First set environment variables, then add:

export RLM_DATA_DIR="$HOME/.rlm-data"
export OLLAMA_URL="http://localhost:11434"

claude mcp add rlm -s user -- uv run --directory "$(pwd)" python -m src.rlm_mcp_server

Option 3: Manual JSON config

Add to ~/.claude/.mcp.json for full control:

{
  "mcpServers": {
    "rlm": {
      "command": "uv",
      "args": ["run", "--directory", "/path/to/rlm", "python", "-m", "src.rlm_mcp_server"],
      "env": {
        "RLM_DATA_DIR": "/path/to/.rlm-data",
        "OLLAMA_URL": "http://localhost:11434"
      }
    }
  }
}

Note: Replace /path/to/rlm with your actual installation path (run pwd in the rlm directory).

Enable Auto-Detection

Enable Claude to use RLM tools automatically without manual invocation:

1. CLAUDE.md Integration Copy CLAUDE.md.example content to your project's CLAUDE.md (or ~/.claude/CLAUDE.md for global) to teach Claude when to reach for RLM tools automatically.

2. Hook Installation Copy the .claude/hooks/ directory to your project to auto-suggest RLM when reading files >25KB:

cp -r .claude/hooks/ /Users/your_username/your-project/.claude/hooks/

The hook provides guidance but doesn't block reads.

3. Skill Reference Copy the .claude/skills/ directory for comprehensive RLM guidance:

cp -r .claude/skills/ /Users/your_username/your-project/.claude/skills/

With these in place, Claude will autonomously detect when to use RLM instead of reading large files directly into context.

Tools

These tools are used by Claude internally when processing large contexts. You don't call them directly—you just ask Claude to analyze large files.

Tool	Purpose
rlm_auto_analyze	One-step analysis — auto-detects type, chunks, and queries
rlm_load_context	Load context as external variable
rlm_inspect_context	Get structure info without loading into prompt
rlm_chunk_context	Chunk by lines/chars/paragraphs
rlm_get_chunk	Retrieve specific chunk
rlm_filter_context	Filter with regex (keep/remove matching lines)
rlm_exec	Execute Python code against loaded context (sandboxed)
rlm_sub_query	Make sub-LLM call on chunk
rlm_sub_query_batch	Process multiple chunks in parallel
rlm_store_result	Store sub-call result for aggregation
rlm_get_results	Retrieve stored results
rlm_list_contexts	List all loaded contexts

Quick Analysis with rlm_auto_analyze

For most use cases, Claude uses rlm_auto_analyze — it handles everything automatically:

rlm_auto_analyze(
    name="my_file",
    content=file_content,
    goal="find_bugs"  # or: summarize, extract_structure, security_audit, answer:<question>
)

What it does automatically:

1. Detects content type (Python, JSON, Markdown, logs, prose, code)
2. Selects optimal chunking strategy
3. Adapts the query for the content type
4. Runs parallel sub-queries
5. Returns aggregated results

Supported goals:

Goal	Description
summarize	Summarize content purpose and key points
find_bugs	Identify errors, issues, potential problems
extract_structure	List functions, classes, schema, headings
security_audit	Find vulnerabilities and security issues
answer:<question>	Answer a custom question about the content

Programmatic Analysis with rlm_exec

For deterministic pattern matching and data extraction, Claude can use rlm_exec to run Python code directly against a loaded context. This is closer to the paper's REPL approach and provides full control over analysis logic.

Tool: rlm_exec

Purpose: Execute arbitrary Python code against a loaded context in a sandboxed subprocess.

Parameters:

• code (required): Python code to execute. Set the result variable to capture output.
• context_name (required): Name of a previously loaded context.
• timeout (optional, default 30): Maximum execution time in seconds.

Features:

• Context available as read-only context variable
• Pre-imported modules: re, json, collections
• Subprocess isolation (won't crash the server)
• Timeout enforcement
• Works on any system with Python (no Docker needed)

Example — Finding patterns in a loaded context:

# After loading a context
rlm_exec(
    code="""
import re
amounts = re.findall(r'\$[\d,]+', context)
result = {'count': len(amounts), 'sample': amounts[:5]}
""",
    context_name="bill"
)

Example Response:

{
  "result": {
    "count": 1247,
    "sample": ["$500", "$1,000", "$250,000", "$100,000", "$50"]
  },
  "stdout": "",
  "stderr": "",
  "return_code": 0,
  "timed_out": false
}

Example — Extracting structured data:

rlm_exec(
    code="""
import re
import json

# Find all email addresses
emails = re.findall(r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b', context)

# Count by domain
from collections import Counter
domains = [e.split('@')[1] for e in emails]
domain_counts = Counter(domains)

result = {
    'total_emails': len(emails),
    'unique_domains': len(domain_counts),
    'top_domains': domain_counts.most_common(5)
}
""",
    context_name="dataset",
    timeout=60
)

When to use rlm_exec vs rlm_sub_query:

Use Case	Tool	Why
Extract all dates, IDs, amounts	rlm_exec	Regex is deterministic and fast
Find security vulnerabilities	rlm_sub_query	Requires reasoning and context
Parse JSON/XML structure	rlm_exec	Standard libraries work perfectly
Summarize themes or tone	rlm_sub_query	Natural language understanding needed
Count word frequencies	rlm_exec	Simple computation, no AI needed
Answer "Why did X happen?"	rlm_sub_query	Requires inference and reasoning

Tip: For large contexts, combine both — use rlm_exec to filter/extract, then rlm_sub_query for semantic analysis of filtered results.

Providers

By default, sub-queries use Claude Haiku 4.5 via the Claude Agent SDK. This works out-of-the-box if you have a Claude API key configured.

Provider	Default Model	Cost	Use Case
claude-sdk	claude-haiku-4-5	~$0.80/1M input	Default, works everywhere
ollama	olmo-3.1:32b	$0	Local inference, requires Ollama

Recursive Sub-Queries

The rlm_sub_query and rlm_sub_query_batch tools support hierarchical decomposition via the max_depth parameter:

• max_depth=0 (default): Flat call, no recursion
• max_depth=1-5: Sub-LLM can use RLM tools (chunk, filter, sub_query, etc.)

Example: Analyzing a massive codebase with 2-level recursion:

rlm_sub_query(
    query="Find all security vulnerabilities",
    context_name="codebase",
    chunk_index=0,
    max_depth=2  # Allow sub-queries to further decompose
)

How it works:

1. When max_depth > 0, the sub-LLM receives RLM tools in its function calling context
2. If the sub-LLM decides to use a tool (e.g., rlm_chunk_context), the agent loop handles it
3. Each recursive call decrements the depth limit until max_depth is reached
4. The response includes recursion metadata: depth_reached and call_trace

Recommended for recursive calls: Use a local model like gemma3:27b via Ollama to avoid cost escalation from deep recursion.

Using Ollama (Free Local Inference)

With Ollama installed locally, you can run sub-queries at zero cost:

1. Install Ollama and pull a model:

   ollama pull gemma3:27b
   

2. Add Ollama URL to your MCP config:

   {
     "mcpServers": {
       "rlm": {
         "command": "uv",
         "args": ["run", "--directory", "/Users/your_username/projects/rlm", "python", "-m", "src.rlm_mcp_server"],
         "env": {
           "RLM_DATA_DIR": "/Users/your_username/.rlm-data",
           "OLLAMA_URL": "http://localhost:11434"
         }
       }
     }
   }
   

3. Specify provider in sub-queries:

   rlm_sub_query(
       query="Summarize this section",
       context_name="my_doc",
       chunk_index=0,
       provider="ollama"  # Use local Ollama instead of default claude-sdk
   )
   

Or for batch processing:

rlm_sub_query_batch(
    query="Extract key points",
    context_name="my_doc",
    chunk_indices=[0, 1, 2, 3],
    provider="ollama",  # Use local Ollama instead of default claude-sdk
    concurrency=4
)

Usage Examples

Basic Pattern

# 1. Load a large document
rlm_load_context(name="report", content=<large document>)

# 2. Inspect structure
rlm_inspect_context(name="report", preview_chars=500)

# 3. Chunk into manageable pieces
rlm_chunk_context(name="report", strategy="paragraphs", size=1)

# 4. Sub-query chunks in parallel
rlm_sub_query_batch(
    query="What is the main topic? Reply in one sentence.",
    context_name="report",
    chunk_indices=[0, 1, 2, 3],
    concurrency=4  # uses claude-sdk by default
)

# 5. Store results for aggregation
rlm_store_result(name="topics", result=<response>)

# 6. Retrieve all results
rlm_get_results(name="topics")

Analyzing Encyclopedia Britannica (11MB)

The flagship example of RLM capabilities — processing the Encyclopedia Britannica, 11th Edition from Project Gutenberg:

# Load the full encyclopedia (11MB, ~2M tokens)
content = open("docs/encyclopedia/merged_encyclopedia.txt").read()
rlm_load_context(name="encyclopedia", content=content)

# Inspect
rlm_inspect_context(name="encyclopedia")
# → 11MB, 184K lines, ~2M tokens

# Chunk for processing
rlm_chunk_context(name="encyclopedia", strategy="paragraphs", size=30)

# Query across the corpus
rlm_sub_query_batch(
    query="Summarize the main topics in this section",
    context_name="encyclopedia",
    chunk_indices=[0, 50, 100, 150],
    provider="claude-sdk"  # or "ollama" for free local inference
)

Extract Topic Catalog:

# Filter for specific subject
rlm_filter_context(
    name="encyclopedia",
    output_name="botany",
    pattern="(?i)(botan|plant|flora|flower|genus)",
    mode="keep"
)

# Analyze filtered content
rlm_auto_analyze(
    name="botany_analysis",
    content=filtered_content,
    goal="answer:List all botanical articles with brief descriptions"
)

Metric	Value
File size	11 MB
Lines	184,000
Tokens	~2M
Processing cost	$0 (Ollama) or ~$1.60 (Haiku)

Data Storage

$RLM_DATA_DIR/
├── contexts/     # Raw contexts (.txt + .meta.json)
├── chunks/       # Chunked versions (by context name)
└── results/      # Stored sub-call results (.jsonl)

Contexts persist across sessions. Chunked contexts are cached for reuse.

Architecture

Claude Code
    │
    ▼
RLM MCP Server
    │
    ├─► claude-sdk (Haiku 4.5) ─► Anthropic API
    │
    └─► ollama ─► Local LLM (gemma3:27b, llama3, etc.)

The key insight: context stays external, not in your prompt. Claude orchestrates; sub-models analyze.

For Contributors: Learning the Codebase

Use these prompts with Claude Code to explore the codebase and learn RLM patterns. The code is the single source of truth.

Understanding the Tools

Read src/rlm_mcp_server.py and list all RLM tools with their parameters and purpose.

Explain the chunking strategies available in rlm_chunk_context.
When would I use each one?

What's the difference between rlm_sub_query and rlm_sub_query_batch?
Show me the implementation.

Understanding the Architecture

Read src/rlm_mcp_server.py and explain how contexts are stored and persisted.
Where does the data live?

How does the claude-sdk provider extract text from responses?
Walk me through _call_claude_sdk.

What happens when I call rlm_load_context? Trace the full flow.

Hands-On Learning

Load the README as a context, chunk it by paragraphs,
and run a sub-query on the first chunk to summarize it.

Show me how to process a large file in parallel using rlm_sub_query_batch.
Use a real example.

I have a 1MB log file. Walk me through the RLM pattern to extract all errors.

Extending RLM

Read the test file and explain what scenarios are covered.
What edge cases should I be aware of?

How would I add a new chunking strategy (e.g., by regex delimiter)?
Show me where to modify the code.

How would I add a new provider (e.g., OpenAI)?
What functions need to change?

Test Corpus: Encyclopedia Britannica

The repository includes excerpts from the Encyclopedia Britannica, 11th Edition (1910-1911) from Project Gutenberg for testing RLM capabilities on large reference documents.

Included Files

File	Size	Description
docs/encyclopedia/merged_encyclopedia.txt	11MB	All slices merged (~2M tokens)

Using for Testing

# Load the full encyclopedia
content = open("docs/encyclopedia/merged_encyclopedia.txt").read()
rlm_load_context(name="encyclopedia", content=content)

# Inspect
rlm_inspect_context(name="encyclopedia")
# → 11MB, 184K lines, ~2M tokens

# Chunk for processing
rlm_chunk_context(name="encyclopedia", strategy="paragraphs", size=30)

# Query across the corpus
rlm_sub_query_batch(
    query="Summarize the main topics in this section",
    context_name="encyclopedia",
    chunk_indices=[0, 50, 100, 150],
    provider="claude-sdk"  # or "ollama" for free local inference
)

Example: Extract Topic Catalog

# Filter for specific subject
rlm_filter_context(
    name="encyclopedia",
    output_name="botany",
    pattern="(?i)(botan|plant|flora|flower|genus)",
    mode="keep"
)

# Analyze filtered content
rlm_auto_analyze(
    name="botany_analysis",
    content=filtered_content,
    goal="answer:List all botanical articles with brief descriptions"
)

Download More Slices

Additional encyclopedia volumes available from Project Gutenberg:

• Search: https://www.gutenberg.org/ebooks/search/?query=encyclopaedia+britannica+11th
• ~130 slices available covering A-Z

Attribution

Encyclopedia Britannica, 11th Edition (1910-1911) sourced from Project Gutenberg. Public domain.

License

MIT