Model Matchmaker: Local hook that cuts AI costs 50-70% and speeds up 60% of requests

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I built a local hook that solves a problem I kept seeing: using Opus for everything (git commits, file renames, etc.) when Haiku/Sonnet work identically at 75-90% less cost.

The Problem

After analyzing weeks of my own prompts:

  • ~60-70% were standard feature work Sonnet handles fine

  • Big chunks were pure git/formatting tasks Haiku handles identically

  • Only ~10-15% genuinely needed Opus

We all know we should switch models. But when you’re in flow, you don’t want to think about the dropdown.

What It Does

Model Matchmaker is a local hook that runs before each prompt:

  • Classifies the task via keyword matching (git ops, feature work, architecture)

  • Blocks if you’re overpaying (Opus for git commit → recommends Haiku)

  • Blocks if you’re underpowered (Sonnet for architecture → recommends Opus)

  • Lets everything else through

  • ! prefix bypasses it completely

Why Local + Why Not a Proxy

Local means:

  • No network calls, no proxy, no attack surface

  • No API costs for blocked requests

  • Fail-open: if it hangs (2-second timeout), Cursor proceeds normally

Compared to Cursor’s Auto mode:

  • Auto is server-side, doesn’t include Haiku or Opus, doesn’t show which model it picked

  • This is client-side, nudges in both directions (down when overpaying, up when underpowered)

Compared to OpenRouter/auto:

  • OpenRouter optimizes server-side routing (you still pay per token)

  • This blocks requests client-side (no API call = $0)

  • They’re complementary—you could use both

Results

Cost savings: 50-70% reduction (cloud API users)

Speed improvement: 60% of requests route to faster models (Haiku responds 3-5x faster than Opus)

Accuracy: 12/12 real test prompts classified correctly after tuning

The unexpected benefit: when simple tasks return in 3-5 seconds instead of 15-20, your entire workflow feels snappier.

Tech Stack

  • Pure bash + python3 (JSON parsing)

  • No dependencies (python3 pre-installed on macOS/Linux)

  • 3 files, 2-minute setup

  • Logs every decision to ~/.cursor/hooks/model-advisor.log (20-char prompt snippet only, for privacy)

Try It

GitHub: GitHub - coyvalyss1/model-matchmaker: Local hook for Cursor and Claude Code that routes prompts to the right model tier. Stop paying Opus prices to rename files. · GitHub

Would love feedback from other Cursor users—does your prompt breakdown look similar? Any patterns I’m missing?

5

UPDATE - Model Matchmaker v2 just shipped with hands-free model switching.

When you try to send on the wrong model, it now:

1. Switches to the recommended model automatically (keyboard automation)

2. Submits your message for you

3. Entire flow takes 3-4 seconds

No more manual switching. No extra Enter presses. Just blocks, switches, and sends.

Enable it:

```bash

# Grant Terminal accessibility permissions first

# System Settings > Privacy & Security > Accessibility > Add Terminal

~/.cursor/hooks/toggle-auto-switch.sh on

```

How it works:

- Uses Cursor’s built-in shortcuts (Cmd+/) + AppleScript

- Proxies through Terminal.app for macOS Accessibility permissions

- Terminal flashes briefly, then auto-closes

- Adapts to Cursor modes (Agent, Plan, Debug, Ask)

Security:

Auto-switch uses input whitelisting, rate limiting, atomic locking, frontmost verification, and scoped keyboard shortcuts to ensure it can only type one of three model names into Cursor’s dropdown—nothing more.

- 14 layers of defense (input validation, rate limiting, atomic locking, frontmost check, etc.)

- Emergency kill switch available

- Full audit logging

- macOS Accessibility permissions required (user-controlled)

- Complete transparency: see SECURITY.md for all details

Tested on hundreds of real prompts. Works reliably on macOS. Disable anytime with `~/.cursor/hooks/toggle-auto-switch.sh off`.

Repo: GitHub - coyvalyss1/model-matchmaker: Local hook for Cursor and Claude Code that routes prompts to the right model tier. Stop paying Opus prices to rename files. · GitHub