Add Codex CLI support; xAI response improvements

demos/llm_routing/codex_router/README.md

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+# Codex Router - Multi-Model Access with Intelligent Routing
+
+Plano extends Codex CLI to access multiple LLM providers through a single interface. This gives you:
+
+1. **Access to Models**: Connect to OpenAI, Anthropic, xAI, Gemini, and local models via Ollama
+2. **Intelligent Routing via Preferences for Coding Tasks**: Configure which models handle specific development tasks:
+   - Code generation and implementation
+   - Code understanding and analysis
+   - Debugging and optimization
+   - Architecture and system design
+
+Uses a [1.5B preference-aligned router LLM](https://arxiv.org/abs/2506.16655) to automatically select the best model based on your request type.
+
+## Benefits
+
+- **Single Interface**: Access multiple LLM providers through the same Codex CLI
+- **Task-Aware Routing**: Requests are analyzed and routed to models based on task type (code generation vs code understanding)
+- **Provider Flexibility**: Add or remove providers without changing your workflow
+- **Routing Transparency**: See which model handles each request and why
+
+## Quick Start
+
+### Prerequisites
+
+```bash
+# Install Codex CLI
+npm install -g @openai/codex
+
+# Install Plano CLI
+pip install planoai
+```
+
+### Step 1: Open the Demo
+
+```bash
+git clone https://github.com/katanemo/arch.git
+cd arch/demos/llm_routing/codex_router
+```
+
+### Step 2: Set API Keys
+
+```bash
+export OPENAI_API_KEY="your-openai-key-here"
+export ANTHROPIC_API_KEY="your-anthropic-key-here"
+export XAI_API_KEY="your-xai-key-here"
+export GEMINI_API_KEY="your-gemini-key-here"
+```
+
+### Step 3: Start Plano
+
+```bash
+planoai up
+# or: uvx planoai up
+```
+
+### Step 4: Launch Codex Through Plano
+
+```bash
+planoai cli-agent codex
+# or: uvx planoai cli-agent codex
+```
+
+By default, `planoai cli-agent codex` starts Codex with `gpt-5.3-codex`. With this demo config:
+
+- `code understanding` prompts are routed to `gpt-5-2025-08-07`
+- `code generation` prompts are routed to `gpt-5.3-codex`
+
+## Monitor Routing Decisions
+
+In a second terminal:
+
+```bash
+sh pretty_model_resolution.sh
+```
+
+This shows each request model and the final model selected by Plano's router.
+
+## Configuration Highlights
+
+`config.yaml` demonstrates:
+
+- OpenAI default model for Codex sessions (`gpt-5.3-codex`)
+- Routing preference override for code understanding (`gpt-5-2025-08-07`)
+- Additional providers (Anthropic, xAI, Gemini, Ollama local) to show cross-provider routing support
+
+## Optional Overrides
+
+Set a different Codex session model:
+
+```bash
+planoai cli-agent codex --settings='{"CODEX_MODEL":"gpt-5-2025-08-07"}'
+```

demos/llm_routing/codex_router/config.yaml

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+version: v0.3.0
+
+listeners:
+  - type: model
+    name: model_listener
+    port: 12000
+
+model_providers:
+  # OpenAI models used by Codex defaults and preference routing
+  - model: openai/gpt-5.3-codex
+    default: true
+    access_key: $OPENAI_API_KEY
+    routing_preferences:
+      - name: code generation
+        description: generating new code snippets, functions, or boilerplate based on user prompts or requirements
+
+  - model: xai/grok-4-1-fast-non-reasoning
+    access_key: $GROK_API_KEY
+    routing_preferences:
+      - name: project understanding
+        description: understand repository structure, codebase, and code files, readmes, and other documentation
+
+  # Additional providers (optional): Codex can route to any configured model
+  # - model: anthropic/claude-sonnet-4-5
+  #   access_key: $ANTHROPIC_API_KEY
+
+  # - model: xai/grok-4-1-fast-non-reasoning
+  #   access_key: $GROK_API_KEY
+
+  - model: ollama/llama3.1
+    base_url: http://localhost:11434
+
+model_aliases:
+  arch.codex.default:
+    target: gpt-5.3-codex
+
+tracing:
+  random_sampling: 100

demos/llm_routing/codex_router/pretty_model_resolution.sh

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+#!/usr/bin/env bash
+# Pretty-print Plano MODEL_RESOLUTION lines from docker logs
+# - hides Arch-Router
+# - prints timestamp
+# - colors MODEL_RESOLUTION red
+# - colors req_model cyan
+# - colors resolved_model magenta
+# - removes provider and streaming
+
+docker logs -f plano 2>&1 \
+| awk '
+/MODEL_RESOLUTION:/ && $0 !~ /Arch-Router/ {
+  # extract timestamp between first [ and ]
+  ts=""
+  if (match($0, /\[[0-9-]+ [0-9:.]+\]/)) {
+    ts=substr($0, RSTART+1, RLENGTH-2)
+  }
+
+  # split out after MODEL_RESOLUTION:
+  n = split($0, parts, /MODEL_RESOLUTION: */)
+  line = parts[2]
+
+  # remove provider and streaming fields
+  sub(/ *provider='\''[^'\'']+'\''/, "", line)
+  sub(/ *streaming=(true|false)/, "", line)
+
+  # highlight fields
+  gsub(/req_model='\''[^'\'']+'\''/, "\033[36m&\033[0m", line)
+  gsub(/resolved_model='\''[^'\'']+'\''/, "\033[35m&\033[0m", line)
+
+  # print timestamp + MODEL_RESOLUTION
+  printf "\033[90m[%s]\033[0m \033[31mMODEL_RESOLUTION\033[0m: %s\n", ts, line
+}'