Backends¶

clinvk supports multiple AI CLI backends, each with unique strengths and characteristics.

Supported Backends¶

Claude Code - Anthropic's AI coding assistant with deep reasoning capabilities
Codex CLI - OpenAI's code-focused CLI tool optimized for code generation
Gemini CLI - Google's Gemini AI with broad knowledge and capabilities

Backend Comparison¶

Feature	Claude Code	Codex CLI	Gemini CLI
Binary	`claude`	`codex`	`gemini`
Default Model	Backend default (or config override)	Backend default (or config override)	Backend default (or config override)
Session Resume	`--resume`	`codex exec resume`	`--resume`
Strengths	Complex reasoning, safety	Code generation	Broad knowledge

Backend Detection¶

clinvk automatically detects available backends by checking for their binaries in your PATH:

clinvk config show

Output includes backend availability summary:

Default Backend: claude

Backends:
  claude:
    model: claude-opus-4-5-20251101
  codex:
    model: o3
  gemini:
    model: gemini-2.5-pro

Available backends:
  claude: available
  codex: not installed
  gemini: available

Selecting Backends¶

Via CLI¶

clinvk --backend claude "prompt"
clinvk -b codex "prompt"
clinvk -b gemini "prompt"

Via Configuration¶

Set a default backend in ~/.clinvk/config.yaml:

default_backend: claude

Via Environment Variable¶

export CLINVK_BACKEND=codex
clinvk "prompt"  # Uses codex

Backend-Specific Options¶

Each backend supports the unified options, plus its own specific flags:

Unified Options¶

These work across all backends:

Option	Description
`model`	Model to use
`approval_mode`	Approval behavior
`sandbox_mode`	File access permissions
`max_turns`	Maximum agentic turns
`max_tokens`	Maximum response tokens

Backend-Specific Flags¶

Pass additional flags via extra_flags in config:

backends:
  claude:
    extra_flags: ["--add-dir", "./docs"]
  codex:
    extra_flags: ["--quiet"]
  gemini:
    extra_flags: ["--sandbox"]

Choosing a Backend¶

Use Claude Code when¶

Working on complex, multi-step tasks
Needing thorough code review and analysis
Safety and accuracy are paramount

Use Codex CLI when¶

Generating boilerplate code
Writing tests
Quick code transformations

Use Gemini CLI when¶

Needing broad knowledge context
Working with documentation
General explanations

Tips¶

Try Multiple Backends

Use clinvk compare --all-backends to see how different backends approach the same problem.

Match Backend to Task

Different backends excel at different tasks. Experiment to find the best fit for your workflow.

Configure Defaults

Set backend-specific models and options in your config file for a personalized experience.