Developer Guide

Current features only: Page-aware AI explanations; iCloud JSON page cache (inf6.pagecache); YAML library viewer (read-only).
Requires OpenAI API key: inf6’s AI explanations need your OpenAI API key. It is stored locally (User Defaults). Get one at platform.openai.com/api-keys.
Fix “Invalid redeclaration of seedInitialDirectory” if you see that build error.
Add/replace iOS & iPadOS App Icons with the required sizes and Contents.json.
Understand JSON vs YAML (what is saved where).

Setup (OpenAI API Key)

Required: An OpenAI API key is mandatory to use AI explanations. / OpenAI の API キーが必須です。

Create/Sign in to OpenAI: Visit platform.openai.com/api-keys and generate a new secret key.
Enter your key in inf6: In the app, open the gear icon → OpenAI API Key, paste the key, then Save.
Test: Open any PDF page and run “Create Explanation”. If the key is missing/invalid, the app shows an error.

Billing & Privacy: Usage is billed by OpenAI per token. Your key stays on‑device (User Defaults). Only your prompts and minimal context are sent to the API.

Overview

inf6 helps you read technical texts and create page-aware AI explanations. Explanations and notes are stored as iCloud JSON (inf6.pagecache), and a read-only YAML viewer lets you browse existing YAML libraries on iPhone and Mac. AI features require your OpenAI API key (see Setup).

Main Features

Page-aware AI Explanations NEW

Create explanations grounded in on-page text (JP/EN). Cancel / retry supported.

iCloud Page Cache (JSON)

Notes and explanations are saved as inf6.pagecache in your iCloud container. Use the same Apple ID to keep devices in sync.

YAML Library Viewer (Read-only)

Browse YAML files stored in iCloud. Great for keeping a structured knowledge library alongside your notes.

Comfortable Reading UI

Zoom HUD, thumbnail sidebar, split view, and detail-pane font scaling for long reading sessions.

Fix: “Invalid redeclaration of `seedInitialDirectory`”

Search in BookLibraryView.swift for seedInitialDirectory and keep only one set of these helpers (macOS & iOS):

// MARK: - Seed initial directory for file/folder pickers
#if os(macOS)
@inline(__always)
private func seedInitialDirectory(_ panel: NSOpenPanel) {
    if let u = BookLibraryView.lastPDFFolderURL() {
        panel.directoryURL = u
    }
}
#endif

#if canImport(UIKit)
@inline(__always)
private func seedInitialDirectory(_ picker: UIDocumentPickerViewController) {
    if let u = BookLibraryView.lastPDFFolderURL() {
        picker.directoryURL = u
    }
}
#endif

Remove duplicate wrappers DocumentFilePickerWrapper / DocumentFolderPickerWrapper if they exist twice.
Remove duplicate “bookmark helpers” blocks (lastPDFFolderURL / rememberPDFFolder) if duplicated.
Clean build (Shift+Cmd+K) and build again.

App Icons (iOS & iPadOS)

Add AppIcon.appiconset inside Assets.xcassets with these required sizes:

iPhone: 20@2x, 20@3x, 29@2x, 29@3x, 40@2x, 40@3x, 60@2x, 60@3x
iPad: 20@1x, 20@2x, 29@1x, 29@2x, 40@1x, 40@2x, 76@1x, 76@2x, 83.5@2x
Marketing: 1024×1024 (no alpha)

Sample Contents.json

{
  "images":[
    {"idiom":"iphone","size":"20x20","scale":"2x","filename":"icon_iphone_20x20@2x.png"},
    {"idiom":"iphone","size":"20x20","scale":"3x","filename":"icon_iphone_20x20@3x.png"},
    {"idiom":"iphone","size":"29x29","scale":"2x","filename":"icon_iphone_29x29@2x.png"},
    {"idiom":"iphone","size":"29x29","scale":"3x","filename":"icon_iphone_29x29@3x.png"},
    {"idiom":"iphone","size":"40x40","scale":"2x","filename":"icon_iphone_40x40@2x.png"},
    {"idiom":"iphone","size":"40x40","scale":"3x","filename":"icon_iphone_40x40@3x.png"},
    {"idiom":"iphone","size":"60x60","scale":"2x","filename":"icon_iphone_60x60@2x.png"},
    {"idiom":"iphone","size":"60x60","scale":"3x","filename":"icon_iphone_60x60@3x.png"},

    {"idiom":"ipad","size":"20x20","scale":"1x","filename":"icon_ipad_20x20@1x.png"},
    {"idiom":"ipad","size":"20x20","scale":"2x","filename":"icon_ipad_20x20@2x.png"},
    {"idiom":"ipad","size":"29x29","scale":"1x","filename":"icon_ipad_29x29@1x.png"},
    {"idiom":"ipad","size":"29x29","scale":"2x","filename":"icon_ipad_29x29@2x.png"},
    {"idiom":"ipad","size":"40x40","scale":"1x","filename":"icon_ipad_40x40@1x.png"},
    {"idiom":"ipad","size":"40x40","scale":"2x","filename":"icon_ipad_40x40@2x.png"},
    {"idiom":"ipad","size":"76x76","scale":"1x","filename":"icon_ipad_76x76@1x.png"},
    {"idiom":"ipad","size":"76x76","scale":"2x","filename":"icon_ipad_76x76@2x.png"},
    {"idiom":"ipad","size":"83.5x83.5","scale":"2x","filename":"icon_ipad_83_5x83_5@2x.png"},

    {"idiom":"ios-marketing","size":"1024x1024","scale":"1x","filename":"icon_marketing_1024x1024.png"}
  ],
  "info":{"version":1,"author":"xcode"}
}

After replacing the icon set, select it in Targets → General → App Icons and Clean Build Folder.

Data Format (JSON & YAML)

Page explanations & notes: saved as iCloud JSON (inf6.pagecache).
YAML Library: viewer only (read-only) at present. Editing UI is not included.

iCloud Sync

Start on iPhone, continue on Mac — your page cache and YAML files stay in step.
OpenAI key & privacy: AI features require your OpenAI API key. The key is stored locally (User Defaults). You control when requests are sent.

Requires iCloud Drive enabled on both devices. Network conditions may affect sync timing.

Screens

Contact

Support / bug reports: support@inf6.com

See Support page for setup (iCloud Drive, permissions) and FAQs.

Download

The app will be available on the App Store for iPhone and Mac (via Mac build). The link will be posted here after review.