# Docfill P0 CLI Design

## Goal

Make the MVP safe enough for a digital employee to call repeatedly from scripts.

## CLI Contract

```bash
docfill run --config task.json --var date=2026-06-18
docfill run -c task.json --var date=2026-06-18 --var department=营销部
```

Exit codes:

- `0`: success.
- `1`: task execution or validation failed.
- `2`: CLI usage error.

Output:

- Success writes a short generated-file summary to stdout.
- Errors write one clear line to stderr with the `docfill:` prefix.

Reserved for later:

- `docfill validate`.
- `--json`.

## P0 Behavior

- Resolve relative paths in config from the config file directory.
- Support config vars and repeated CLI vars.
- CLI vars override config vars.
- Per-row data overrides vars during template rendering.
- Generated `_row` is always the 1-based row number.
- Support SQLite `params` for `?` query placeholders.
- Support Excel `header_row`, 1-based, default `1`.
- Do not overwrite existing output files unless `output.overwrite` is `true`.
- Sanitize placeholder values only when rendering output file paths.
- Fail if any template placeholder is missing from the current row context.
- Fail if any `{{field}}` remains after rendering.

## Config Shape

```json
{
  "vars": {
    "date": "2026-06-18"
  },
  "data": {
    "type": "sqlite",
    "path": "./data.db",
    "query": "select name, done from daily where date = ?",
    "params": ["{{date}}"]
  },
  "template": {
    "path": "./template.docx"
  },
  "output": {
    "path": "./out/report_{{date}}_{{name}}_{{_row}}.docx",
    "overwrite": false
  }
}
```