llm-tldr 1.4.1

Token-efficient code analysis for LLMs. 5-layer stack: AST, Call Graph, CFG, DFG, PDG. 95% token savings. 17 languages.

TLDR: Code Analysis for AI Agents

Give LLMs exactly the code they need. Nothing more.

# One-liner: Install, index, search
pip install llm-tldr && tldr warm . && tldr semantic "what you're looking for" .

Your codebase is 100K lines. Claude's context window is 200K tokens. Raw code won't fit—and even if it did, the LLM would drown in irrelevant details.

TLDR extracts structure instead of dumping text. The result: 95% fewer tokens while preserving everything needed to understand and edit code correctly.

pip install llm-tldr
tldr warm .                    # Index your project
tldr context main --project .  # Get LLM-ready summary

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How It Works

TLDR builds 5 analysis layers, each answering different questions:

┌─────────────────────────────────────────────────────────────┐
│ Layer 5: Program Dependence  → "What affects line 42?"      │
│ Layer 4: Data Flow           → "Where does this value go?"  │
│ Layer 3: Control Flow        → "How complex is this?"       │
│ Layer 2: Call Graph          → "Who calls this function?"   │
│ Layer 1: AST                 → "What functions exist?"      │
└─────────────────────────────────────────────────────────────┘

Why layers? Different tasks need different depth:

• Browsing code? Layer 1 (structure) is enough
• Refactoring? Layer 2 (call graph) shows what breaks
• Debugging null? Layer 5 (slice) shows only relevant lines

The daemon keeps indexes in memory for 100ms queries instead of 30-second CLI spawns.

Architecture

┌──────────────────────────────────────────────────────────────────┐
│                         YOUR CODE                                │
│  src/*.py, lib/*.ts, pkg/*.go                                    │
└───────────────────────────┬──────────────────────────────────────┘
                            │ tree-sitter
                            ▼
┌──────────────────────────────────────────────────────────────────┐
│                     5-LAYER ANALYSIS                             │
│  ┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐     │
│  │   AST   │→│  Calls  │→│   CFG   │→│   DFG   │→│   PDG   │     │
│  │   L1    │ │   L2    │ │   L3    │ │   L4    │ │   L5    │     │
│  └─────────┘ └─────────┘ └─────────┘ └─────────┘ └─────────┘     │
└───────────────────────────┬──────────────────────────────────────┘
                            │ bge-large-en-v1.5
                            ▼
┌──────────────────────────────────────────────────────────────────┐
│                    SEMANTIC INDEX                                │
│  1024-dim embeddings in FAISS  →  "find JWT validation"          │
└───────────────────────────┬──────────────────────────────────────┘
                            │
                            ▼
┌──────────────────────────────────────────────────────────────────┐
│                       DAEMON                                     │
│  In-memory indexes  •  100ms queries  •  Auto-lifecycle          │
└──────────────────────────────────────────────────────────────────┘

The Semantic Layer: Search by Behavior

The real power comes from combining all 5 layers into searchable embeddings.

Every function gets indexed with:

• Signature + docstring (L1)
• What it calls + who calls it (L2)
• Complexity metrics (L3)
• Data flow patterns (L4)
• Dependencies (L5)
• First ~10 lines of actual code

This gets encoded into 1024-dimensional vectors using bge-large-en-v1.5. The result: search by what code does, not just what it says.

# "validate JWT" finds verify_access_token() even without that exact text
tldr semantic "validate JWT tokens and check expiration" .

Why this works: Traditional search finds authentication in variable names and comments. Semantic search understands that verify_access_token() performs JWT validation because the call graph and data flow reveal its purpose.

Setting Up Semantic Search

# Build the semantic index (one-time, ~2 min for typical project)
tldr warm /path/to/project

# Search by behavior
tldr semantic "database connection pooling" .

Embedding dependencies (sentence-transformers, faiss-cpu) are included with pip install llm-tldr. The index is cached in .tldr/cache/semantic.faiss.

Keeping the Index Fresh

The daemon tracks dirty files and auto-rebuilds after 20 changes, but you need to notify it when files change:

# Notify daemon of a changed file
tldr daemon notify src/auth.py --project .

Integration options:

1. Git hook (post-commit):

   git diff --name-only HEAD~1 | xargs -I{} tldr daemon notify {} --project .
   

2. Editor hook (on save):

   tldr daemon notify "$FILE" --project .
   

3. Manual rebuild (when needed):

   tldr warm .  # Full rebuild
   

The daemon auto-rebuilds semantic embeddings in the background once the dirty threshold (default: 20 files) is reached.

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The Workflow

Before Reading Code

tldr tree src/                      # See file structure
tldr structure src/ --lang python   # See functions/classes

Before Editing

tldr extract src/auth.py            # Full file analysis
tldr context login --project .      # LLM-ready summary (95% savings)

Before Refactoring

tldr impact login .                 # Who calls this? (reverse call graph)
tldr change-impact                  # Which tests need to run?

Debugging

tldr slice src/auth.py login 42     # What affects line 42?
tldr dfg src/auth.py login          # Trace data flow

Finding Code by Behavior

tldr semantic "validate JWT tokens" .   # Natural language search

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Quick Setup

1. Install

pip install llm-tldr

2. Index Your Project

tldr warm /path/to/project

This builds all analysis layers and starts the daemon. Takes 30-60 seconds for a typical project, then queries are instant.

3. Start Using

tldr context main --project .   # Get context for a function
tldr impact helper_func .       # See who calls it
tldr semantic "error handling"  # Find by behavior

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Real Example: Why This Matters

Scenario: Debug why user is null on line 42.

Without TLDR:

1. Read the 150-line function
2. Trace every variable manually
3. Miss the bug because it's hidden in control flow

With TLDR:

tldr slice src/auth.py login 42

Output: Only 6 lines that affect line 42:

3:   user = db.get_user(username)
7:   if user is None:
12:      raise NotFound
28:  token = create_token(user)  # ← BUG: skipped null check
35:  session.token = token
42:  return session

The bug is obvious. Line 28 uses user without going through the null check path.

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Command Reference

Exploration

Command	What It Does
tldr tree [path]	File tree
tldr structure [path] --lang <lang>	Functions, classes, methods
tldr search <pattern> [path]	Text pattern search
tldr extract <file>	Full file analysis

Analysis

Command	What It Does
tldr context <func> --project <path>	LLM-ready summary (95% savings)
tldr cfg <file> <function>	Control flow graph
tldr dfg <file> <function>	Data flow graph
tldr slice <file> <func> <line>	Program slice

Cross-File

Command	What It Does
tldr calls [path]	Build call graph
tldr impact <func> [path]	Find all callers (reverse call graph)
tldr dead [path]	Find unreachable code
tldr arch [path]	Detect architecture layers
tldr imports <file>	Parse imports
tldr importers <module> [path]	Find files that import a module

Semantic

Command	What It Does
tldr warm <path>	Build all indexes (including embeddings)
tldr semantic <query> [path]	Natural language code search

Diagnostics

Command	What It Does
tldr diagnostics <file>	Type check + lint
tldr change-impact [files]	Find tests affected by changes
tldr doctor	Check/install diagnostic tools

Daemon

Command	What It Does
tldr daemon start	Start background daemon
tldr daemon stop	Stop daemon
tldr daemon status	Check status

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Supported Languages

Python, TypeScript, JavaScript, Go, Rust, Java, C, C++, Ruby, PHP, C#, Kotlin, Scala, Swift, Lua, Elixir

Language is auto-detected or specify with --lang.

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MCP Integration

For AI tools (Claude Desktop, Claude Code):

Claude Desktop - Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "tldr": {
      "command": "tldr-mcp",
      "args": ["--project", "/path/to/your/project"]
    }
  }
}

Claude Code - Add to .claude/settings.json:

{
  "mcpServers": {
    "tldr": {
      "command": "tldr-mcp",
      "args": ["--project", "."]
    }
  }
}

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Configuration

.tldrignore - Exclude Files

TLDR respects .tldrignore (gitignore syntax) for all commands including tree, structure, search, calls, and semantic indexing:

# Auto-create with sensible defaults
tldr warm .  # Creates .tldrignore if missing

Default exclusions:

• node_modules/, .venv/, __pycache__/
• dist/, build/, *.egg-info/
• Binary files (*.so, *.dll, *.whl)
• Security files (.env, *.pem, *.key)

Customize by editing .tldrignore:

# Add your patterns
large_test_fixtures/
vendor/
data/*.csv

CLI Flags:

# Add patterns from command line (can be repeated)
tldr --ignore "packages/old/" --ignore "*.generated.ts" tree .

# Bypass all ignore patterns
tldr --no-ignore tree .

Settings - Daemon Behavior

Create .tldr/config.json for daemon settings:

{
  "semantic": {
    "enabled": true,
    "auto_reindex_threshold": 20
  }
}

Setting	Default	Description
enabled	true	Enable semantic search
auto_reindex_threshold	20	Files changed before auto-rebuild

Monorepo Support

For monorepos, create .claude/workspace.json to scope indexing:

{
  "active_packages": ["packages/core", "packages/api"],
  "exclude_patterns": ["**/fixtures/**"]
}

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Performance

Metric	Raw Code	TLDR	Improvement
Tokens for function context	21,000	175	99% savings
Tokens for codebase overview	104,000	12,000	89% savings
Query latency (daemon)	30s	100ms	300x faster

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Deep Dive

For the full architecture explanation, benchmarks, and advanced workflows:

Full Documentation

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License

Apache 2.0 - See LICENSE file.