Runtimes
AI Runner provides a single interface across AI coding tools. Pick your runtime once, and the same flags, shebangs, and scripts work identically. AI Runner handles the mapping.
Supported Runtimes
| Runtime | Flag | Default Model | Ecosystem | Install |
|---|
| Claude Code | --cc | claude-opus-4-6 | Anthropic | curl -fsSL https://claude.ai/install.sh | bash |
| Codex CLI | --codex | gpt-5.4 | OpenAI | npm install -g @openai/codex |
Selecting a Runtime
# Auto-detect (tries Claude Code first, falls back to Codex)
ai task.md
# Explicit selection
ai --cc task.md # Claude Code
ai --codex task.md # Codex CLI
# Save as default
ai --codex --set-default # Always use Codex
ai --clear-default # Reset to auto-detect
#!/usr/bin/env -S ai --codex --high
Analyze this codebase with OpenAI's flagship model.
Universal Flags
Most flags work identically with both runtimes. AI Runner maps them to each tool’s native equivalents:
| Category | Flags | Behavior |
|---|
| Model tiers | --opus/--high, --sonnet/--mid, --haiku/--low | Mapped to each runtime’s models |
| Custom model | --model <id> | Passed to runtime’s model flag |
| Effort | --effort <low|medium|high|max> | Controls reasoning depth |
| Local providers | --ollama, --lmstudio | Both runtimes support local models |
| Azure | --azure | Maps to each runtime’s Azure service |
| Permissions | --auto, --bypass, --skip | Mapped to each runtime’s equivalents |
| Resume | --resume | Resume previous conversation |
| Streaming | --live, --quiet | Real-time output with heartbeat |
| Defaults | --set-default, --clear-default | Persists tool + provider + model |
| Scripting | Shebangs, variables, pipes, stdin | Identical behavior |
Cross-Interpreter Model Tiers
The same tier flag selects each runtime’s equivalent model:
| Tier | Flag | Claude Code | Codex CLI |
|---|
| High | --opus / --high | claude-opus-4-6 | gpt-5.4 |
| Mid | --sonnet / --mid | claude-sonnet-4-6 | gpt-5.3-codex |
| Low | --haiku / --low | claude-haiku-4-5 | gpt-5.4-mini |
ai --high task.md # Claude Code: Opus 4.6
ai --codex --high task.md # Codex: gpt-5.4
Cross-Interpreter Effort Levels
Control how deeply the model reasons:
| AI Runner | Claude Code | Codex CLI |
|---|
--effort low | --effort low | -c model_reasoning_effort=low |
--effort medium | --effort medium | -c model_reasoning_effort=medium |
--effort high | --effort high | -c model_reasoning_effort=high |
--effort max | --effort max | -c model_reasoning_effort=xhigh |
ai --effort high task.md # Claude Code: deeper reasoning
ai --codex --effort max task.md # Codex: maximum reasoning (xhigh)
Cross-Interpreter Providers
| Flag | Claude Code | Codex CLI |
|---|
--ollama | Ollama (Anthropic-compat API) | Ollama (--oss) |
--lmstudio | LM Studio (Anthropic-compat) | LM Studio (--oss) |
--azure | Azure Foundry (Anthropic models) | Azure OpenAI (GPT models) |
--apikey | Anthropic API key | Force OpenAI API key (vs browser auth) |
--aws | AWS Bedrock | Not supported |
--vertex | Google Vertex AI | Not supported |
--vercel | Vercel AI Gateway | Not supported |
--pro | Claude Pro subscription | Not supported |
--profile | Not supported | Config.toml profile (OpenRouter, Mistral, etc.) |
--azure maps to different services per runtime: Azure Foundry (Anthropic) for Claude Code, Azure OpenAI (GPT) for Codex. The user writes the same flag; AI Runner handles the translation.
Cross-Interpreter Permissions
| AI Runner | Claude Code | Codex CLI | Safety Level |
|---|
| (default) | Ask for approval | Ask for approval | Manual |
--auto | AI classifier decides | Sandboxed auto | Smart auto |
--bypass | All auto, no classifier | Sandboxed auto | Permissive |
--skip | Zero safety checks | Zero safety + no sandbox | Nuclear |
--skip bypasses ALL safety on both runtimes. Only use with trusted scripts in trusted directories.
Runtime-Specific Features
Claude Code Only
These flags require Claude Code and will error with Codex:
--aws — AWS Bedrock--vertex — Google Vertex AI--vercel — Vercel AI Gateway--pro — Claude Pro subscription--team — Agent Teams--chrome — Browser automation
Codex CLI Only
--profile <name> — Select a named config profile from ~/.codex/config.toml
ai --codex --profile openrouter task.md
ai --codex --profile azure task.md
~/.codex/config.toml:
[model_providers.openrouter]
name = "OpenRouter"
base_url = "https://openrouter.ai/api/v1"
env_key = "OPENROUTER_API_KEY"
[model_providers.azure]
name = "Azure OpenAI"
base_url = "https://YOUR_RESOURCE.openai.azure.com/openai/v1"
env_key = "AZURE_OPENAI_API_KEY"
Authentication
Claude Code
Uses Anthropic authentication:
- Claude Pro/Max subscription (browser login)
- API key (
ANTHROPIC_API_KEY)
- Cloud provider credentials (AWS, GCP, Azure)
Codex CLI
Uses OpenAI authentication:
- Browser login (default): Run
codex login once, then Codex uses stored tokens
- API key: Set
OPENAI_API_KEY or CODEX_API_KEY in environment or ~/.ai-runner/secrets.sh
- Use
--apikey to force API key mode (for CI/CD)
# Browser auth (default — no env var needed)
ai --codex task.md
# Force API key auth
ai --codex --apikey task.md
Same Script, Both Runtimes
A script written for one runtime works on the other:
#!/usr/bin/env -S ai --high
Analyze the architecture of this codebase and summarize the key patterns.
./analyze.md # Uses default runtime
ai --cc ./analyze.md # Force Claude Code
ai --codex ./analyze.md # Force Codex CLI
Script Portability
Scripts are portable across runtimes. If a script includes interpreter-specific flags, running it on another runtime produces a warning but continues normally:
# Script with Claude Code-specific --chrome flag
#!/usr/bin/env -S ai --auto --chrome
Test the login flow in the browser.
ai --codex ./test-login.md
# [AI Runner] Warning: --chrome is not supported by Codex CLI, ignoring
# (script runs normally without browser automation)
--help output and caches them by version. Unsupported flags are warned and skipped. Flag+value pairs (like --max-turns 5) are skipped together.
This means you can write scripts that use the full power of one runtime and safely run them on another — they degrade gracefully instead of failing.