# Docfill MVP Design

## Goal

Build the smallest local Go command-line tool that a digital employee can call to fill Word or Excel templates from Excel or SQLite data.

## MVP Scope

- Input data: `.xlsx` table or SQLite query result.
- Template files: `.docx` or `.xlsx`.
- Placeholder syntax: `{{column_name}}`.
- Output: one generated file per input row.
- Invocation: `docfill run --config task.json`.

## Explicit Non-Goals

- No web UI.
- No permission system.
- No workflow engine.
- No template designer.
- No direct business-system integration.
- No AI guessing of fields.
- No complex Word layout manipulation.

## Config Shape

```json
{
  "data": {
    "type": "excel",
    "path": "./data.xlsx",
    "sheet": "Sheet1"
  },
  "template": {
    "path": "./template.docx"
  },
  "output": {
    "path": "./out/report_{{name}}_{{_row}}.docx"
  }
}
```

For SQLite, `data` uses `type: "sqlite"` and `query`.

## Constraints

- Keep the implementation boring and inspectable.
- Infer template behavior from file extension.
- Treat Excel first row or SQL column names as placeholder keys.
- If a Word placeholder is split across Word XML runs, MVP may not replace it; users should type placeholders as plain contiguous text.