OpenCode English Prompt Polisher

OpenCode plugin that checks each user prompt and writes a polished English proposal when the prompt is not English or needs English cleanup.

The checker uses OpenCode's configured model/auth by creating a temporary OpenCode session. Proposal mode runs the check asynchronously; rewrite mode waits for it before OpenCode continues.

Features

• Uses only OpenCode for prompt checking.
• Proposes English versions for non-English prompts.
• Polishes grammatically incorrect or unclear English prompts.
• Writes proposals to ~/opencode-english-prompt-polisher.md by default.
• Optionally creates one Notion database entry per proposal.
• Skips its own internal checker prompts to avoid recursion.
• Deletes temporary checker sessions by default.

Reusable Core

Reusable prompt-polishing logic lives in the english-prompt-polisher package. This package keeps only the OpenCode adapter: hook wiring, message dedupe, mode dispatch, rewrite mutation, background scheduling, temporary checker sessions, OpenCode logging, and OpenCode-specific checker options.

OpenCode-specific hook, session, and logging code lives directly under src/.

Install From npm

This repository depends on the npm package english-prompt-polisher for reusable prompt-polishing logic.

Add the plugin to your OpenCode config:

{
	"$schema": "https://opencode.ai/config.json",
	"plugin": [
		[
			"opencode-english-prompt-polisher",
			{
				"mode": "proposal",
				"outputFile": "~/opencode-english-prompt-polisher.md",
				"checker": {
					"agent": "general",
					"model": "current",
					"deleteSession": true,
				},
				"notion": {
					"enabled": true,
					"token": "{env:ENGLISH_PROMPT_POLISHER_NOTION_TOKEN}",
					"databaseId": "{env:ENGLISH_PROMPT_POLISHER_NOTION_DATABASE_ID}",
				},
			},
		],
	],
}

Restart OpenCode after changing config. OpenCode loads plugins only at startup.

Options

| Option | Default | Description | | ----------------------- | --------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- | | mode | proposal | Use proposal to write suggestions in the background, or rewrite to replace the user prompt before OpenCode sends it to the model. | | outputFile | ~/opencode-english-prompt-polisher.md | Markdown file that receives proposals. | | maxChars | 4000 | Maximum prompt characters sent to the checker. In rewrite mode, longer prompts are left unchanged. | | includeOriginal | true | Include the original prompt in the Markdown output. | | checker.agent | general | OpenCode agent used for the temporary checker session. | | checker.model | current | Use the current message model, or set provider/model. | | checker.deleteSession | true | Delete temporary checker sessions after each check. | | notion.enabled | false | Create Notion database entries. | | notion.token | unset | Notion integration token. | | notion.databaseId | unset | Direct Notion database ID. | | notion.titleProperty | auto-detect | Notion title property name. |

Rewrite Mode

Set mode to rewrite when OpenCode should receive the polished prompt instead of the original user text:

{
	"$schema": "https://opencode.ai/config.json",
	"plugin": [
		[
			"opencode-english-prompt-polisher",
			{
				"mode": "rewrite",
				"checker": {
					"agent": "general",
					"model": "current",
				},
			},
		],
	],
}

Rewrite mode waits for the checker before OpenCode continues. If the checker fails or decides no rewrite is needed, the original prompt is left unchanged.

Notion Setup

1. Create a Notion integration and copy its token.
2. Share the target database with the integration.
3. Export the values before starting OpenCode:

export ENGLISH_PROMPT_POLISHER_NOTION_TOKEN="secret_..."
export ENGLISH_PROMPT_POLISHER_NOTION_DATABASE_ID="..."

4. Reference the values from the plugin config with OpenCode env expansion:

"notion": {
  "enabled": true,
  "token": "{env:ENGLISH_PROMPT_POLISHER_NOTION_TOKEN}",
  "databaseId": "{env:ENGLISH_PROMPT_POLISHER_NOTION_DATABASE_ID}"
}

The database must have a title property. These optional properties are filled only when they exist with matching Notion types:

• Detected Language: rich text
• Conversation ID: rich text
• Created At: date

The full reason, original prompt, and proposed English prompt are stored in the Notion page body.

Output Example

## 2026-06-13T12:00:00.000Z

- Conversation ID: ses_123
- Message ID: msg_456
- Detected Language: Russian
- Reason: Prompt is written in Russian and should be translated to English.

### Original Prompt

```text
Создай плагин для OpenCode
```

### Proposed English Prompt

```text
Create a plugin for OpenCode.
```

Notes

• In proposal mode, the original user prompt is not modified or blocked.
• In rewrite mode, the user prompt is modified in place before OpenCode sends it to the model.
• Proposal output is written as supporting output for the user to review only in proposal mode.
• If the checker or Notion write fails, the plugin logs a warning and lets the original prompt continue.
• Prompt checking runs in the background only in proposal mode, so proposals can appear after OpenCode has already started responding.
• Because every prompt requires an extra OpenCode model call, this plugin can increase token usage.