Calto

Model selection for Claude Code

The right Claude model.Without breaking your flow.

Calto helps Claude Code choose a model for the task, while you keep coding.

Get started See how it works

Works with your existing Claude Code setup. Claude usage is billed by your provider as usual.

calto claudeIllustration

  1. Rename a variable across one file

    Haiku

    Small, well-scoped edit

  2. Write tests for the auth module

    Sonnet

    Moderate multi-file work

  3. Plan a storage-layer migration

    Opus

    Open-ended design reasoning

  4. Follow-up fix in the same thread

    Sonnet

    Kept — switching would drop the warm cache

waiting for next task
Illustrative example — not real activity, decisions or benchmarks.

How it works

Measured choices, not guesswork.

Task-based selection

When you hand Claude Code a task, Calto measures how demanding it looks and suggests the model that fits — lighter models for small, well-defined edits; stronger ones for open-ended reasoning.

Cache-aware switching

Changing models mid-conversation means rebuilding context. Calto only switches when the change is likely worth it, and stays put when your current session is already warm.

You stay in charge

Pick a model yourself any time and Calto steps aside. It suggests a fit — it doesn't promise a particular result.

Built for people who'd rather be coding.

  1. 01

    Stop switching models by hand

    No more pausing to decide whether a task deserves a bigger model. Keep typing; Calto makes the call.

  2. 02

    Selection that follows the task

    A quick rename and an architecture plan are different jobs. Calto looks at what you asked and picks accordingly.

  3. 03

    Decisions you can see

    Every choice comes with a short reason, so you always know which model handled what — and why.

  4. 04

    Your setup, unchanged

    Calto runs alongside the Claude Code you already use. No new editor, no new workflow to learn.

Get going

A few commands, then back to work.

Install the CLI, sign in once with a Calto key, and start Claude Code through Calto. Calto is currently a private evaluation — invite only, no payment involved.

Installation guide Read the docs
Install preview
# 1. Install the provided local package file (replace the path):
npm install -g "/path/to/calto-cli-VERSION.tgz"

# 2. Point the CLI at the Calto API (origin supplied by your evaluation contact):
export CALTO_API_ORIGIN=https://calto-api.onrender.com

# 3. Sign in with your Calto API key (hidden prompt):
calto auth login

# 4. Check your setup, then start Claude Code through Calto:
calto doctor
calto claude

Preview — local evaluation package; not on a public registry.