FreeRouter — Smart LLM Router for OpenClaw

Stop overpaying for AI. Every message to your AI assistant costs money — a simple "hello" shouldn't cost the same as "prove the Riemann hypothesis." FreeRouter automatically routes each request to the right model based on complexity.

The Problem

• 🔥 Wasted money — Running Claude Opus ($15/$75 per 1M tokens) for every message, even "what's 2+2?"
• 🤷 No control — Can't switch models mid-conversation without editing config files and restarting
• 📊 Blind routing — Your AI shows "freerouter/auto" instead of telling you which model actually answered
• 🧠 No adaptive thinking — OpenClaw's built-in thinking levels (/think low, /think high) are just prompt hints. Anthropic deprecated manual thinking for Opus 4.6 — it now requires the native thinking: { type: "adaptive" } API parameter, which OpenClaw doesn't send
• 🔧 Complex setup — Existing routers need separate servers, Docker, complex infra

The Solution

FreeRouter is an OpenClaw plugin that:

• Classifies every request in <1ms using a 14-dimension weighted scorer (no LLM needed for classification)
• Routes to the cheapest model that can handle it — Kimi for "hello", Opus for architecture design
• Sends native adaptive thinking — Automatically passes thinking: { type: "adaptive" } to Anthropic's API for Opus 4.6, and thinking: { type: "enabled", budget_tokens: N } for Sonnet. No prompt hacks — real API-level thinking control that OpenClaw doesn't support natively
• Reports the real model name — You see anthropic/claude-opus-4-6, not freerouter/auto
• Lets you override anytime — Just say "use opus" in plain English

Install

openclaw plugins install openclaw-freerouter

Then run the setup wizard:

openclaw freerouter setup

Or configure manually — see Configuration below.

Switch Models Anytime

The killer feature: switch models using natural language, slash commands, or session locks.

Just Say It (Natural Language)

No slash commands needed. Just talk:

What you say	What happens
use opus	Switches to Claude Opus for this message
switch to sonnet	Switches to Claude Sonnet
try kimi	Switches to Kimi
let's use opus	Switches to Opus
please use sonnet	Switches to Sonnet
can you use haiku	Switches to Haiku
use opus: explain quantum computing	Uses Opus for this specific prompt
use opus, what is 2+2?	Same — model + prompt in one message
go back to auto	Return to automatic routing

Lock a Model for the Whole Session

When you know the task is important and you want Opus (or any model) for everything:

What you say	What happens
use opus for this session	🔒 Locks ALL messages to Opus
switch to sonnet from now on	🔒 Locks to Sonnet
stick with opus	🔒 Locks to Opus
keep using sonnet	🔒 Locks to Sonnet
/lock opus	🔒 Same thing, slash command
/unlock	🔓 Back to auto-routing
/lock status	Shows current lock state

Session locks expire after 4 hours of inactivity.

When FreeRouter Isn't Sure

If your request is ambiguous, FreeRouter asks before switching:

You: "opus please" FreeRouter: 🤔 Did you want to switch to anthropic/claude-opus-4-6? Reply yes or no. You: "yes" FreeRouter: ✅ Confirmed!

This prevents accidental switches when you're just talking about a model.

Slash Commands (Power Users)

Command	Effect
/opus What is 2+2?	Per-prompt: Opus for this message only
/sonnet Write a poem	Per-prompt: Sonnet
/kimi Quick answer	Per-prompt: Kimi
/haiku Translate this	Per-prompt: Haiku
/simple What is 2+2?	Per-prompt: use SIMPLE tier model
/max Prove this theorem	Per-prompt: use REASONING tier model
[opus] Deep analysis	Bracket syntax (same as /opus)

Supported Model Aliases

Alias	Model
opus, opus-4, opus-4.6	anthropic/claude-opus-4-6
sonnet, sonnet-4, sonnet-4.5	anthropic/claude-sonnet-4-5
sonnet-4.6	anthropic/claude-sonnet-4-6
haiku, haiku-4, haiku-4.5	anthropic/claude-haiku-4-5
kimi, kimi-k2, k2.5	kimi-coding/kimi-for-coding

Adaptive Thinking (Native API-Level)

This is a key reason FreeRouter exists.

The problem: OpenClaw's built-in /think low|medium|high commands are prompt-level hints — they add text like "think harder" to your prompt. This is unreliable and doesn't use Anthropic's actual thinking API. Worse, Anthropic deprecated manual thinking (type: "enabled") for Opus 4.6 — it now only supports type: "adaptive", where the model decides how much to think based on the task.

What FreeRouter does: Sends the real thinking parameter directly to Anthropic's API:

Model	Thinking Mode	What's Sent
Claude Opus 4.6	Adaptive (always)	thinking: { type: "adaptive" }
Claude Sonnet 4.5	Enabled with budget	thinking: { type: "enabled", budget_tokens: 4096 }
Others (Kimi, Haiku)	Off	No thinking parameter

Why this matters:

• Adaptive thinking lets Opus 4.6 decide how much reasoning it needs — simple questions get quick answers, complex proofs get deep thinking chains
• You get the full benefit of Claude's extended thinking without managing budgets
• The X-FreeRouter-Thinking response header tells you exactly which thinking mode was used

Configure in your plugin config:

"thinking": {
  "adaptive": ["claude-opus-4-6"],           // Models that use adaptive (always-on)
  "enabled": {
    "models": ["claude-sonnet-4-5"],          // Models that get explicit thinking
    "budget": 4096                             // Token budget for thinking
  }
}

How Routing Works

1. You send a message → OpenClaw forwards to FreeRouter
2. FreeRouter's 14-dimension classifier scores the request in <1ms (0.035ms average)
3. Based on the score, it picks the best tier:

Tier	Default Model	Use Case	Cost
SIMPLE	Kimi K2.5	Quick lookups, translations, "hello"	$0.50/1M
MEDIUM	Claude Sonnet 4.5	Code, creative writing, moderate tasks	$3/$15/1M
COMPLEX	Claude Opus 4.6	Architecture, deep analysis	$15/$75/1M
REASONING	Claude Opus 4.6	Proofs, formal logic, step-by-step	$15/$75/1M

4. Forwards to the real provider API (Anthropic, Kimi, OpenAI, etc.)
5. Returns the response with the actual model name — not "freerouter/auto"

Scoring Dimensions

The classifier evaluates 14 weighted dimensions without calling any LLM:

• Token count, code presence, reasoning markers, technical terms
• Creative markers, simple indicators, multi-step patterns
• Question complexity, imperative verbs, constraints
• Output format, references, negation, domain specificity
• Agentic task indicators (multi-tool, multi-step workflows)

Supports multilingual classification: English, Chinese, Japanese, Russian, German, Vietnamese, Arabic, Korean, and more.

Configure

After install, add to your openclaw.json:

{
  // 1. Set FreeRouter as your default model
  "agents": {
    "defaults": {
      "model": {
        "primary": "freerouter/freerouter/auto",
        "fallbacks": ["anthropic/claude-opus-4-6"]
      }
    }
  },

  // 2. Add FreeRouter as a provider
  "providers": {
    "freerouter": {
      "baseUrl": "http://127.0.0.1:18801/v1",
      "api": "openai-completions"
    }
  },

  // 3. Plugin config
  "plugins": {
    "entries": {
      "openclaw-freerouter": {
        "enabled": true,
        "config": {
          "port": 18801,
          "host": "127.0.0.1",
          "tiers": {
            "SIMPLE":    { "primary": "kimi-coding/kimi-for-coding", "fallback": ["anthropic/claude-haiku-4-5"] },
            "MEDIUM":    { "primary": "anthropic/claude-sonnet-4-5", "fallback": ["anthropic/claude-opus-4-6"] },
            "COMPLEX":   { "primary": "anthropic/claude-opus-4-6", "fallback": [] },
            "REASONING": { "primary": "anthropic/claude-opus-4-6", "fallback": [] }
          },
          "thinking": {
            "adaptive": ["claude-opus-4-6"],
            "enabled": { "models": ["claude-sonnet-4-5"], "budget": 4096 }
          },
          "defaultTier": "MEDIUM"
        }
      }
    }
  }
}

Then restart: openclaw gateway restart

CLI Commands

Command	Description
openclaw freerouter status	Show config, tier mapping, and live stats
openclaw freerouter setup	Interactive setup wizard
openclaw freerouter test	Quick 5-query classification smoke test
openclaw freerouter doctor	Diagnose issues (port conflicts, missing config, etc.)
openclaw freerouter port <n>	Change the proxy port
openclaw freerouter reset	Show default config for recovery

Chat Commands

Command	Description
/freerouter	Show routing stats in chat
/freerouter-doctor	Quick health check

Port Conflicts

If port 18801 is in use, change it:

{ "plugins": { "entries": { "openclaw-freerouter": { "config": { "port": 18802 } } } } }

Set "port": 0 to disable the HTTP proxy entirely.

Troubleshooting

# Check if everything is working
openclaw freerouter doctor

# Quick classification test
openclaw freerouter test

# Reset to defaults
openclaw freerouter reset

Response Headers

Every proxied response includes metadata headers:

• X-FreeRouter-Model — Actual model used (e.g., anthropic/claude-opus-4-6)
• X-FreeRouter-Tier — Classification tier (SIMPLE/MEDIUM/COMPLEX/REASONING)
• X-FreeRouter-Thinking — Thinking mode (off/adaptive/enabled)
• X-FreeRouter-Reasoning — Why this model was chosen

API Endpoints

The HTTP proxy exposes:

• POST /v1/chat/completions — OpenAI-compatible chat endpoint
• GET /v1/models — List available models
• GET /health — Health check
• GET /stats — Routing statistics
• GET /sessions/locks — Active session locks
• DELETE /sessions/locks — Clear all session locks

Tests

npm test  # Runs all 212 tests

• test-freerouter.mjs — Classification, multilingual, edge cases, performance
• test-resilience.mjs — Fallback chains, bad configs, recovery, port conflicts
• test-overrides.mjs — Model overrides, session locks, natural language switching

License

MIT