Typing Lens

Typing Lens is a private typing coach for macOS. It is built for developers and writers who are interested in improving their typing accuracy and performance.

The product:

• real typing should inform practice;
• raw typing should not be stored;
• speed only matters when accuracy and correction cost hold;
• practice only counts when it transfers to text that was not just drilled.

The public browser demo is live at https://typing-lens.pages.dev/. The Mac app is the full product: it builds a local profile from aggregate evidence and uses that profile to prescribe short, targeted practice.

See docs/dogfood.md, docs/architecture.md, and docs/roadmap.md for the current cohort and distribution gates.

Privacy Model

Stored locally:

• short pattern keys such as supported bigrams/trigrams or coarse metric keys;
• aggregate timing summaries, rates, sample sizes, confidence, and fact IDs;
• bounded numeric history for trends and practice summaries.

Never stored:

• Raw typed passages or replayable keystroke streams;
• Prompt text, passage text, or typed attempts from practice;
• Clipboard contents, URLs, window titles, or document titles;
• Bridge payload logs or AI prompts containing raw typing.

The app excludes sensitive app categories before aggregation, respects Secure Event Input, has a visible paused/recording state, and can export or purge the local SQLite database.

Requirements

• macOS 14+
• US-QWERTY primary layout for capture-oriented use
• Xcode with Swift 6
• Node.js 22+
• pnpm 10

This repo uses SwiftPM and pnpm workspaces. There is no tracked .xcodeproj.

Build The Mac App

Install dependencies:

pnpm install

Create one stable local code-signing identity. This matters because macOS TCC binds Input Monitoring grants to the app's code signature. Ad-hoc signing gives each rebuild a new identity, so capture can silently fail even when System Settings still appears to grant permission.

One local setup path:

1. Open Keychain Access.
2. Choose Certificate Assistant -> Create a Certificate.
3. Name it TypingLens Dev.
4. Set Identity Type to Self-Signed Root.
5. Set Certificate Type to Code Signing.
6. Add it to your shell:

export TYPING_LENS_CODESIGN_IDENTITY="TypingLens Dev"

Build and launch:

# Builds the web coach, builds the Swift app, assembles `build/Typing Lens.app`,
# signs it with your identity, quits any running copy, and opens the new bundle.
scripts/build-mac-app.sh --launch

# Reset Input Monitoring, rebuild, and relaunch if capture stops after a signing change:
scripts/build-mac-app.sh --reset-input-monitoring --launch

# Remove local app data:
tccutil reset ListenEvent dev.typin.TypingLens
rm -rf "build/Typing Lens.app" ~/Library/Application\ Support/TypingLens

# For non-capture work only, ad-hoc signing is available behind an explicit opt-in:
TYPING_LENS_ALLOW_ADHOC_TCC=1 scripts/build-mac-app.sh

Run Checks

Full local validation:

pnpm validate

Package examples:

swift test --package-path swift/Packages/Store
swift test --package-path apps/mac
pnpm -F @typing-lens/site test
pnpm -F @typing-lens/web-coach test

Swift package tests do not need Input Monitoring. Only a launched .app build needs a signing identity and macOS permission.

Licenses

• apps/mac/ and swift/: AGPL-3.0-or-later
• packages/: MIT

See LICENSE for scope and full license texts.