Local Brain

Local Brain

Delegate complex codebase exploration to local Ollama models. Local Brain excels at multi-step tasks requiring reasoning, not simple commands.

When to Use Local Brain

Local Brain adds 10-70 seconds of LLM inference overhead per query. Use it for tasks where AI reasoning provides value, not for simple commands.

Use Local Brain for:

• Multi-step exploration ("Find all error handlers and explain how they work")
• Code review and analysis ("Review recent changes for potential issues")
• Understanding unfamiliar code ("Explain how authentication flows through the system")
• Tasks requiring judgment ("What patterns does this codebase use?")
• When you don't know which files or commands to look at

Do NOT use Local Brain for:

• Simple file listing (use ls or find directly — 1000x faster)
• Git status/log (use git log directly — 1000x faster)
• Reading a specific known file (use cat or your editor)
• Any single-command operation where you know what to run

Performance reality: A simple "list files" query takes 12-70 seconds via Local Brain vs 5ms via ls. The value is in the reasoning, not the tool execution.

Installation

Install local-brain:

uv pip install local-brain

Or with pipx:

pipx install local-brain

Requirements:

• Ollama running locally (https://ollama.ai)
• A model pulled (e.g., ollama pull qwen3)

Usage

local-brain "prompt"                    # Ask anything (auto-selects best model)
local-brain -v "prompt"                 # Show tool calls
local-brain -d "prompt"                 # Show step-by-step debug output
local-brain -m qwen3-coder:30b "prompt" # Specific model
local-brain --trace "prompt"            # Enable OTEL tracing
local-brain --list-models               # Show available models
local-brain --root /path/to/project "prompt"  # Set project root
local-brain doctor                      # Check system health

Health Check

Verify your setup is working correctly:

local-brain doctor

This checks:

• Ollama is installed and running
• Recommended models are available
• Tools execute correctly
• Optional tracing dependencies

Example output:

🔍 Local Brain Health Check

Checking Ollama...
  ✅ Ollama is installed (ollama version is 0.13.1)

Checking Ollama server...
  ✅ Ollama server is running (9 models)

Checking recommended models...
  ✅ Recommended models installed: qwen3:latest

Checking tools...
  ✅ Tools working (9 tools available)

Checking optional features...
  ✅ OTEL tracing available (--trace flag)

========================================
✅ All checks passed! Local Brain is ready.

Examples

Focus on tasks where AI reasoning adds value:

# Code review and analysis (good use case)
local-brain "Review the recent git changes and identify potential issues"
local-brain "Analyze the error handling patterns in this codebase"

# Understanding unfamiliar code (good use case)
local-brain "Explain how the authentication system works end-to-end"
local-brain "What design patterns does this codebase use?"

# Multi-step exploration (good use case)
local-brain "Find all TODO comments and categorize them by urgency"
local-brain "Trace how user input flows through the validation layer"

# Generate content requiring context (good use case)
local-brain "Generate a commit message based on the staged changes"
local-brain "Summarize what changed in the last 5 commits"

Model Selection Guide

Choose the right model for your task:

For Code Exploration (Recommended)

Use qwen3-coder:30b for faster exploration tasks:

local-brain -m qwen3-coder:30b "Find all error handlers and explain how they work"
local-brain -m qwen3-coder:30b "What validation patterns are used in this codebase?"
local-brain -m qwen3-coder:30b "Trace the data flow from API endpoint to database"

Why: 2.5x faster than qwen3:30b (12-20s vs 35-70s per query), direct tool usage.

For Complex Reasoning

Use qwen3:30b for tasks requiring deeper analysis:

local-brain -m qwen3:30b "Analyze the architecture and suggest improvements"
local-brain -m qwen3:30b "Review recent changes for security vulnerabilities"
local-brain -m qwen3:30b "Explain how authentication works end-to-end"

Why: More thorough reasoning, better at synthesis and review tasks.

Tips for Better Results

Use --debug to see what the model is doing step-by-step:

local-brain -d -m qwen3-coder:30b "Analyze the test coverage gaps"

Avoid these models (broken or unreliable tool calling):

• qwen2.5-coder:* - Outputs JSON instead of executing tools
• llama3.2:1b - Too small, hallucinates paths
• deepseek-r1:* - No tool support at architecture level

If no model is specified, Local Brain auto-selects the best installed model.

Observability

Debug Mode (--debug or -d)

See step-by-step progress with the --debug flag:

local-brain --debug "Analyze error handling in the auth module"

This shows:

• Step number and duration
• Tool calls with arguments
• Result preview (truncated)
• Token usage per step

Example output:

[debug] Model: qwen3-coder:30b
[debug] Project root: /path/to/project

[Step 1] (4.2s)
  Tool: list_directory(path='.', pattern='**/*')
  Result:
    src/main.py
    src/utils.py
    ... (15 lines total)
  Tokens: 2634 in / 42 out

OTEL Tracing (--trace)

Enable OpenTelemetry tracing to visualize agent execution with detailed timing and metrics:

local-brain --trace "Review recent changes and identify potential issues"

This captures:

• Agent execution timeline (total duration)
• Individual steps (planning, execution, final answer)
• LLM calls with token counts
• Tool invocations with inputs/outputs
• Timing for each operation

Visualizing Traces with Jaeger (Recommended)

For real-time visualization of agent execution, use Jaeger:

1. Start Jaeger (one-time setup):

docker run -d \
  --name jaeger \
  -p 16686:16686 \
  -p 4318:4318 \
  jaegertracing/all-in-one

2. Run local-brain with tracing:

local-brain --trace -m qwen3-coder:30b "Analyze the test patterns in this codebase"

3. View in Jaeger UI: Open http://localhost:16686 and select:

• Service: local-brain
• Operation: CodeAgent.run

You'll see a waterfall timeline showing:

CodeAgent.run (5.1s total)
├── Step 1 (2.04s)
│   ├── LiteLLMModel.generate (2.03s) ← LLM latency
│   └── list_directory (1.5ms) ← Tool execution
└── Step 2 (3.09s)
    ├── LiteLLMModel.generate (3.09s)
    └── FinalAnswerTool (0.1ms)

Click any span to see details: tokens used, arguments, outputs, errors.

Install Tracing Dependencies

For JSON console output only (no Jaeger):

pip install local-brain[tracing]

For Jaeger visualization, also install:

pip install opentelemetry-exporter-otlp

Combining Flags for Maximum Insight

Use all three flags together for complete visibility:

local-brain --trace --debug -m qwen3-coder:30b "Review recent changes for security issues"

This gives:

• --trace → OTEL spans in Jaeger (timing, tokens, architecture)
• --debug → Real-time step progress to stderr (what's happening now)
• --verbose → Tool calls in main output (what was called)

Note: --debug and --trace can be combined.

Security

All file operations are restricted to the project root (path jailing):

• Files outside the project directory cannot be read
• Shell commands execute within the project root
• Sensitive files (.env, .pem, SSH keys) are blocked
• Only read-only shell commands are allowed
• All tool outputs are truncated (200 lines / 20K chars max)
• Tool calls have timeouts (30 seconds default)

Available Tools

The model assumes these tools are available and uses them directly:

File Tools

• read_file(path) - Read file contents at a given path. Large files are truncated (200 lines / 20K chars). Has 30s timeout. Restricted to project root.
• list_directory(path, pattern) - List files in path matching a glob pattern. Supports recursive patterns:
  • * - files in directory only
  • **/* - ALL files recursively (use this to discover nested structures)
  • **/*.py - all Python files recursively
  • src/**/*.js - all JS files under src/ Excludes hidden files and common ignored directories. Returns up to 100 files. Has 30s timeout.
• file_info(path) - Get file metadata (size, type, modified time) for a given path. Has 30s timeout.

Code Navigation Tools (New in v0.6.0)

• search_code(pattern, file_path, ignore_case) - AST-aware code search. Unlike simple grep, shows intelligent context around matches (function/class boundaries). Supports Python, JavaScript, TypeScript, Go, Rust, Ruby, Java, C/C++.
• list_definitions(file_path) - Extract class/function definitions from a source file. Shows signatures and docstrings without full implementation code. Great for understanding file structure quickly.

Git Tools

• git_diff(staged, file_path) - Show code changes. Use staged=True for staged changes. Optionally provide a file_path. Output is truncated.
• git_status() - Check repo status. Output is truncated.
• git_changed_files(staged, include_untracked) - List changed files. Use staged=True for staged files, include_untracked=True to include untracked files. Output is truncated.
• git_log(count) - View commit history. count specifies number of commits (max 50). Output is truncated.

All tools return human-readable output or error messages on failure.

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