litellm/tests/test_litellm/router_strategy
shin-bot-litellm 1be30f5129
feat(router): Add complexity-based auto routing strategy (#21789)
* feat(router): Add complexity-based auto routing strategy

Adds a rule-based routing strategy that classifies requests by complexity
and routes them to appropriate models - with zero API calls and sub-millisecond
latency.

## Features

- **Zero external API calls** - all scoring is local
- **Sub-millisecond latency** - typically <1ms per classification
- **Weighted multi-dimensional scoring** across 7 dimensions:
  - Token count (short=simple, long=complex)
  - Code presence (code keywords → complex)
  - Reasoning markers ("step by step" → reasoning tier)
  - Technical terms (domain complexity)
  - Simple indicators ("what is" → simple, negative weight)
  - Multi-step patterns (numbered steps)
  - Question complexity (multiple questions)
- **Configurable tier boundaries** and model mappings
- **Reasoning override** - 2+ reasoning markers force REASONING tier

## Usage

```yaml
model_list:
  - model_name: smart-router
    litellm_params:
      model: auto_router/complexity_router
      complexity_router_config:
        tiers:
          SIMPLE: gpt-4o-mini
          MEDIUM: gpt-4o
          COMPLEX: claude-sonnet-4
          REASONING: o1-preview
```

Inspired by ClawRouter: https://github.com/BlockRunAI/ClawRouter

## Files Added

- litellm/router_strategy/complexity_router/complexity_router.py - Main router class
- litellm/router_strategy/complexity_router/config.py - Configuration and defaults
- litellm/router_strategy/complexity_router/__init__.py - Package exports
- litellm/router_strategy/complexity_router/README.md - Documentation
- tests/test_litellm/router_strategy/test_complexity_router.py - Test suite (37 tests)

## Files Modified

- litellm/router.py - Integration with pre_routing_hook
- litellm/types/router.py - New config params

* feat(router): Add complexity-based auto routing strategy

Adds a new rule-based routing strategy that classifies requests by complexity
and routes them to appropriate models - without any external API calls.

## Features
- Weighted scoring across 7 dimensions: token count, code presence, reasoning
  markers, technical terms, simple indicators, multi-step patterns, questions
- Maps to 4 tiers: SIMPLE, MEDIUM, COMPLEX, REASONING
- Each tier configurable to a different model
- Zero API calls, <1ms latency
- Inspired by ClawRouter

## Configuration
```yaml
model_list:
  - model_name: smart_router
    litellm_params:
      model: auto_router/complexity_router
      complexity_router_config:
        tiers:
          SIMPLE: gemini-2.0-flash
          MEDIUM: gpt-4o-mini
          COMPLEX: claude-sonnet-4
          REASONING: claude-opus-4
```

## Use Cases
- Cost optimization: route simple queries to cheaper models
- Quality optimization: route complex queries to capable models
- Zero configuration: works out of the box with sensible defaults

* feat(router): Add complexity-based auto routing strategy

Adds a new rule-based routing strategy that classifies requests by complexity
and routes them to appropriate models - without any external API calls.

- Weighted scoring across 7 dimensions: token count, code presence, reasoning
  markers, technical terms, simple indicators, multi-step patterns, questions
- Maps to 4 tiers: SIMPLE, MEDIUM, COMPLEX, REASONING
- Each tier configurable to a different model
- Zero API calls, <1ms latency
- Inspired by ClawRouter

```yaml
model_list:
  - model_name: smart_router
    litellm_params:
      model: auto_router/complexity_router
      complexity_router_config:
        tiers:
          SIMPLE: gemini-2.0-flash
          MEDIUM: gpt-4o-mini
          COMPLEX: claude-sonnet-4
          REASONING: claude-opus-4
```

- Cost optimization: route simple queries to cheaper models
- Quality optimization: route complex queries to capable models
- Zero configuration: works out of the box with sensible defaults

* feat: add enterprise presets for complexity router

Adds preset configurations for different cloud providers:
- bedrock: AWS Bedrock (Claude models)
- vertex: Google Vertex AI (Gemini models)
- azure: Azure OpenAI (GPT + o1)
- standard: Direct API (OpenAI + Anthropic)
- cost_optimized: Maximum savings (Gemini Flash + cheaper models)

Usage:
```yaml
complexity_router_config:
  preset: bedrock  # or vertex, azure, standard, cost_optimized
```

* feat(ui): update auto router submit handler for complexity router

- Handle complexity_router model type in submit handler
- Generate correct litellm_params for complexity router:
  - model: auto_router/complexity_router
  - complexity_router_config: { tiers: { SIMPLE, MEDIUM, COMPLEX, REASONING } }
- Keep existing semantic router handling intact
- Add success notification with router type name

* docs: update PR description with UI changes

* chore: remove preset feature, keep simple tier config

* fix: exclude complexity_router from auto_router check

The _is_auto_router_deployment() was matching all auto_router/* models,
causing complexity_router to fail initialization. Now it explicitly
excludes auto_router/complexity_router which has its own handler.

* fix(complexity_router): Address Greptile review feedback

Fixes 5 issues flagged in code review:

1. **Mutable singleton mutation bug** - Now always creates a new
   ComplexityRouterConfig instance instead of reusing DEFAULT_COMPLEXITY_CONFIG
   singleton, preventing cross-instance config pollution.

2. **Substring matching false positives** - Added word boundaries (spaces)
   to short keywords like 'ok', 'try', 'api', 'git', 'node', 'java', 'vue'
   to prevent matching within longer words (e.g., 'capital' matching 'api').

3. **Redundant message extraction** - Simplified to single reverse loop that
   extracts both last user message and last system prompt efficiently.

4. **Unused imports** - Removed unused DEFAULT_CREATIVE_KEYWORDS and
   DEFAULT_MULTI_STEP_PATTERNS imports.

5. **Missing async_pre_routing_hook tests** - Added comprehensive tests for:
   - Multi-turn conversations
   - List-type content handling
   - No user message case
   - Empty string content
   - Message preservation
   - Singleton mutation prevention

* fix(complexity_router): Address Greptile review feedback

- Use word boundary matching for short keywords (<5 chars) to avoid
  false positives (e.g., 'api' matching 'capital', 'git' matching 'digital')
- Remove 'ok' from simple keywords (too many false positives)
- Add tests for keyword false positive prevention
- Fix test expectations for edge cases (empty string content, list content)

Addresses: 2/5 Greptile score feedback on PR #21789

* docs(auto_routing): Add complexity router documentation

- Add Complexity Router section to auto_routing.md
- Include comparison table with semantic auto router
- Add Python SDK and Proxy Server configuration examples
- Document all configuration options (tier boundaries, token thresholds, dimension weights)
- Explain how complexity scoring works

* feat(complexity_router): Add eval suite + tune scoring parameters

Added comprehensive evaluation suite with 29 test cases covering:
- SIMPLE tier: greetings, definitions, factual questions
- MEDIUM tier: technical explanations, comparisons, debugging
- COMPLEX tier: architecture design, complex coding
- REASONING tier: explicit reasoning requests
- Regression tests: substring false positive prevention

Tuned scoring parameters based on eval results:
- Lowered tier boundaries (0.15/0.35/0.60) for better tier distribution
- Increased code/technical weights (0.30/0.25) for complex prompts
- Reduced simple indicator weight (0.05) to avoid over-penalizing
- Fixed 'hey'/'hi' keywords to require leading space

Eval results: 29/29 passed (100%)

* fix(complexity_router): Address Greptile review round 2

1. **Empty user message handling** - Changed from falsy check to None check
   to properly distinguish 'no user message' from 'empty string message'

2. **ReDoS prevention** - Changed 'first.*then' to 'first.*?then' (non-greedy)
   to prevent regex backtracking on pathological inputs

3. **Documentation sync** - Updated README.md to match actual config values:
   - Tier boundaries: 0.15/0.35/0.60 (not 0.25/0.50/0.75)
   - Dimension weights: tokenCount=0.10, codePresence=0.30, technicalTerms=0.25,
     simpleIndicators=0.05, multiStepPatterns=0.03, questionComplexity=0.02

4. **Missing UI component** - Added ComplexityRouterConfig.tsx with:
   - Tier-to-model dropdown selectors
   - Descriptions and examples for each tier
   - How classification works explanation

5. **Inline import comment** - Added explanation for why ComplexityRouter
   import is inline (matches AutoRouter pattern, avoids circular imports)

* docs(auto_routing): fix dimension weights and tier boundaries to match config.py defaults

* fix(complexity_router): skip empty string content in async_pre_routing_hook

* fix(router): remove or {} masking None complexity_router_config

* fix(config): remove unused DEFAULT_MULTI_STEP_PATTERNS and DEFAULT_CREATIVE_KEYWORDS exports

* fix(complexity_router): use word boundary matching for all single-word keywords, avoid double-scanning reasoning keywords

* fix(router): clarify circular import comment for ComplexityRouter

* docs(README): fix token thresholds to match config.py defaults

* test(complexity_router): add false positive tests for error/class/merge keyword matching

* fix(complexity_router): align .get() fallbacks with config.py defaults, document system prompt scoring

* fix(config): deduplicate keywords across code and technical lists

---------

Co-authored-by: OpenClaw Assistant <assistant@openclaw.ai>
Co-authored-by: Ishaan Jaffer <ishaanjaffer0324@gmail.com>
2026-02-21 13:23:37 -08:00
..
test_auto_router.py fix mapped test 2025-07-25 07:24:42 -07:00
test_base_routing_strategy.py Simplify experimental multi-instance rate limiter - more accurate (#11424) 2025-06-07 11:10:55 -07:00
test_budget_limiter_hotpath.py fix(router): remove repeated provider parsing in budget limiter hot path (#21043) 2026-02-12 20:05:55 -08:00
test_complexity_router.py feat(router): Add complexity-based auto routing strategy (#21789) 2026-02-21 13:23:37 -08:00
test_router_tag_routing.py feat(tag-routing): support toggling tag matching between ANY and ALL (#18776) 2026-01-08 23:39:03 +05:30