OpenCode for GenOffice

Cross-platform tool that points an installed GenOffice at OpenCode Zen or Go models via an OpenAI chat-completions compatible endpoint, using your own API key.

Works on Windows, Linux, and macOS. Requires only Node.js >= 18 — no other dependencies (the asar reader/writer is built in).

What it does

GenOffice has no OPENAI_BASE_URL-style env var. Its built-in custom provider already appends /chat/completions to any baseUrl and sends Authorization: Bearer <key>, but the ai:get-settings IPC handler force-resets the provider to genspark.

This tool:

1. Backs up app.asar (and ai-settings.json if present) into <install>/resources/backups/ with a timestamp.
2. Extracts app.asar, removes the settings.provider = "genspark"; line(s) from out/main/index.js, injects a config-driven User-Agent hook into the custom provider's request headers, injects a reasoning_content passthrough in openAiMessages (required by thinking-mode models), repacks, and replaces the installed asar.
3. Writes/merges ai-settings.json in the GenOffice user-data dir selecting the custom provider with your key, model, and base URL.
4. restore puts everything back from the backup.

Verified on the real v0.7.x bundle: the patched out/main/index.js is byte-identical to the original except the removed force-reset lines, and the repacked asar is readable by standard asar tooling. The app's Electron fuses have asar-integrity validation disabled, so the patched asar loads normally.

Installation

Important

GenOffice must already be installed — this tool patches the installed app, it does not install GenOffice itself.

Requires Node.js >= 18 — no other dependencies (the asar reader/writer is built in).

# Clone the repo and enter it
git clone --depth 1 https://github.com/sekedus/opencode-for-genoffice.git
cd opencode-for-genoffice

# Option 1: run directly from the repo (no install needed)
node patch-genoffice.mjs <command> [options]

# Option 2 (optional): install globally, adds the `ocfgo` command
npm install -g .

Usage

node patch-genoffice.mjs <command> [options]

# or, if installed globally (Option 2):
ocfgo <command> [options]

Commands

Command	Description
patch	Apply the patch (default). Automatically backs up first.
restore	Restore the original app.asar from the latest backup.
status	Show install location, patch state, and available backups.

Options

Option	Description
--provider <zen|go>	Endpoint provider (default: zen). zen = pay-per-use, go = subscription.
--api-key <key>	OpenCode API key, Zen or Go (required for patch)
--model <model>	Model id (default: big-pickle for zen, deepseek-v4-pro for go)
--base-url <url>	Base URL, no trailing slash (default: https://opencode.ai/zen/v1 for zen, https://opencode.ai/zen/go/v1 for go)
--ua <ua>	User-Agent header sent to the AI endpoint (default: opencode-for-genoffice/<version> from package.json)
--install-dir <dir>	GenOffice install dir (auto-detected if omitted)
--user-data <dir>	GenOffice user-data dir (auto-detected if omitted)
--backup-dir <dir>	Backup dir (default: <install>/resources/backups)
--dry-run	Show what would be done without changing anything
--yes, -y	Skip confirmation prompts
--help, -h	Show help

Examples

# Patch with defaults (big-pickle, Zen)
node patch-genoffice.mjs patch --api-key sk-xxxx

# Patch against OpenCode Go (subscription)
node patch-genoffice.mjs patch --api-key sk-xxxx --provider go

# Patch with a free model
node patch-genoffice.mjs patch --api-key sk-xxxx --model deepseek-v4-flash-free

# Patch with a custom User-Agent header
node patch-genoffice.mjs patch --api-key sk-xxxx --ua "opencode-for-genoffice/1.0.0"

# Go provider with a specific model
node patch-genoffice.mjs patch --api-key sk-xxxx --provider go --model glm-5.1

# Dry run first (no changes)
node patch-genoffice.mjs patch --api-key sk-xxxx --dry-run

# Check state
node patch-genoffice.mjs status

# Undo
node patch-genoffice.mjs restore

Note

If you installed globally (Option 2), the same commands work with ocfgo instead of node patch-genoffice.mjs.

Install locations (auto-detected)

OS	Install dir	User-data dir
Windows	%LOCALAPPDATA%\Programs\GenOffice	%APPDATA%\GenOffice
macOS	/Applications/GenOffice.app/Contents/Resources	~/Library/Application Support/GenOffice
Linux	/opt/GenOffice, /usr/lib/genoffice, ~/.local/share/GenOffice, snap/flatpak paths	~/.config/GenOffice

If auto-detection fails (e.g. a custom install path), pass --install-dir and --user-data explicitly. On Linux, if the install dir is root-owned, run with sudo.

Models

Both providers serve OpenAI-compatible models via /chat/completions with Authorization: Bearer <key>. The same API key works for Zen and Go — they are part of the same platform (Zen is pay-per-use, Go is a fixed subscription).

Zen (--provider zen, default)

Pay-per-use; includes free models. Chat-completions ids:

• Free: big-pickle, deepseek-v4-flash-free, mimo-v2.5-free, hy3-free, laguna-s-2.1-free, nemotron-3-ultra-free, nemotron-3.5-lightning-free
• Paid: deepseek-v4-pro, deepseek-v4-flash, minimax-m3, minimax-m2.7, minimax-m2.5, glm-5.2, glm-5.1, glm-5, kimi-k2.5, kimi-k2.6, kimi-k2.7-code, kimi-k3

Fetch the full list: https://opencode.ai/zen/v1/models

Go (--provider go)

Fixed subscription ($5 first month, then $10/month), open-source models only. Only the chat-completions models work with GenOffice's custom provider (MiniMax/Qwen on Go use the Anthropic /messages dialect and are not supported here). Chat-completions ids:

• deepseek-v4-pro, deepseek-v4-flash, glm-5.3, glm-5.2, glm-5.1, kimi-k3, kimi-k2.7-code, kimi-k2.6, mimo-v2.5, mimo-v2.5-pro, hy3

Fetch the full list: https://opencode.ai/zen/go/v1/models

How the patch works (technical)

• The code change in out/main/index.js inside resources/app.asar is:
  1. Remove settings.provider = "genspark"; (2 occurrences in v0.8.155: the active ai:get-settings handler and a dormant sheets variant).
  2. Inject a config-driven User-Agent hook into the custom provider's fetch headers in both request paths (the non-streaming chat call and the streaming turn the AI panel actually uses): ...(config2.userAgent ? { "User-Agent": config2.userAgent } : {}). The value is read from ai-settings.json, so --ua can be changed by re-running patch without touching the asar again.
  3. Register a webRequest.onBeforeSendHeaders handler that rewrites the User-Agent header for /chat/completions requests. This is required because GenOffice's AI requests can fall back to Chromium's net.fetch (when Node's fetch fails at the network layer, e.g. under VPN/proxy), and Chromium silently drops a User-Agent header set in fetch headers — it sends its own Electron UA instead. The handler reads the UA from ai-settings.json at request time.
  4. Inject a reasoning_content passthrough in openAiMessages: assistant history turns now include ...(m.reasoning_content ? { reasoning_content: m.reasoning_content } : {}). Thinking-mode providers (DeepSeek, Qwen, Kimi, GLM) require the previous assistant's reasoning_content to be echoed back on follow-up requests that carry tool calls, or they reject the turn with HTTP 400 ("The reasoning_content in the thinking mode must be passed back to the API"). The renderer bundles capture streaming reasoning_content into history; this injection forwards it when the patched renderer is present.
• resolveAiSettings() already honors a stored provider/providers, so once the force-reset is gone, provider: "custom" from ai-settings.json is used.
• The custom provider builds POST {baseUrl}/chat/completions with Authorization: Bearer <apiKey> — exactly the OpenCode Zen shape.
• ai-settings.json is merged: existing providers are preserved, custom is set/overwritten, and provider is set to custom. userAgent defaults to opencode-for-genoffice/<version> (from package.json); pass --ua to override it.
• Re-running patch on an already-patched install skips all asar work (the original backup stays the restore point) and only rewrites ai-settings.json. If the asar is patched but missing the User-Agent or reasoning-echo support (e.g. patched by an older version), it is re-patched to add it without creating a new backup.

Updating GenOffice

GenOffice updates replace the installed app files, which overwrites the patched app.asar — the patch must be re-applied after every update. Your data (the user-data dir with ai-settings.json) is preserved by the update, so your provider, key, model, and base URL carry over. This applies the same way on Windows, Linux, and macOS (see the install locations table above for the per-OS paths).

What you need to update

Component	Needed?	Why
Installed app	Yes	This is what runs. Update it (auto-update or new installer), then re-patch.
User-data dir	No	Preserved automatically by the update. ai-settings.json survives.

Steps

1. Close GenOffice — the tool refuses to run while the app is open.

2. Update the app — let it auto-update, or install the new version over the existing one (same install dir).

3. Re-run the patch with your usual flags:

   ocfgo patch --api-key sk-xxxx

   The tool detects the fresh (unpatched) asar, backs it up, and re-applies the patch. Your ai-settings.json is merged/rewritten automatically.

4. Restart GenOffice and verify the AI panel works.

Caveats

• Old backups become stale. After an update, re-running patch creates a new backup of the new original asar, so restore stays correct for the new version.
• Version drift. If a new version changes the bundle (renamed functions, moved code), the patch anchors may not match. The tool warns instead of silently breaking ("Could not find...", "unsupported version"). In that case, extract the new app.asar and update the anchors in patch-genoffice.mjs — this is the only scenario where the source code matters.
• Auto-update is the main hazard — it can silently replace app.asar at any time. Consider disabling the updater or scripting the re-patch.

Notes & caveats

• Close GenOffice before patching/restoring. The tool refuses to run while the app is running (file locks on Windows).
• Auto-updates overwrite app.asar. After a GenOffice update, re-run the patch (see Updating GenOffice).
• restore uses the latest backup. Backups are timestamped and kept in <install>/resources/backups/ (plus a manifest.json history).
• The app is not digitally signed and has asar-integrity validation disabled, so the patched asar loads without issue.
• This is an unofficial modification. Verify the OpenCode Zen terms of service and your API key before use.

License

This project is licensed under the GPL-3.0 License - see the LICENSE file for details.