---
name: email_mime_message_rungs
description: "Create an email that has both a plain-text and formatted version of your message plus one or more file attachments, with a subject line that can include accents or non-English characters. email_mime_message_rungs: An RFC 5322 email file written with the standard library email package: a multipart/mi"
---
# email_mime_message_rungs (a Neruva verified skill for `email`)
Create an email that has both a plain-text and formatted version of your message plus one or more file attachments, with a subject line that can include accents or non-English characters.
Verified helper code for `email`, python. Entry points: `make_attachment`, `build_email_message`, `write_message_to_file`.
Code hash sha256 `e703247724c778af571d6984d5b80b10986a1b8cdc9894ab83eb660c0e58f9b3`, signed (ed25519). Banked by `legacy-dev`.
## One call
Call `build(**args)` with an object matching this schema. You do not have to write code or match the helper signatures below.
```json
{
"type": "object",
"properties": {
"from_addr": {
"type": "string",
"description": "Value for the From header, placed verbatim (e.g. 'sysadmin@neruva.io')."
},
"to_addr": {
"type": "string",
"description": "Value for the To header, placed verbatim (e.g. 'jane@acme.test')."
},
"subject": {
"type": "string",
"description": "Value for the Subject header; may contain non-ASCII characters, which will be RFC2047-encoded and round-trip via policy.default parsing."
},
"plain_text": {
"type": "string",
"description": "Exact body text for the text/plain alternative part (utf-8 encoded)."
},
"html_text": {
"type": "string",
"description": "Exact body markup for the text/html alternative part (utf-8 encoded)."
},
"attachment": {
"type": "object",
"description": "The single attachment to include in the message.",
"properties": {
"filename": {
"type": "string",
"description": "Filename to declare for the attachment, e.g. 'report.csv'."
},
"content_type": {
"type": "string",
"description": "MIME content type of the attachment, e.g. 'text/csv'."
},
"content": {
"type": "string",
"description": "Attachment content as a string (UTF-8 encoded) or base64/plain text depending on need; passed through as-is to make_attachment which will UTF-8 encode strings."
}
},
"required": [
"filename",
"content_type",
"content"
]
},
"date": {
"type": "string",
"description": "Optional ISO 8601 date-time string (e.g. '2024-05-01T12:00:00+00:00') for the Date header. If omitted, the current UTC time is used. If timezone-naive, UTC is assumed."
},
"output_path": {
"type": "string",
"description": "Filesystem path where the resulting .eml file will be written. Returned by build() on success."
}
},
"required": [
"from_addr",
"to_addr",
"subject",
"plain_text",
"html_text",
"attachment",
"output_path"
]
}
```
Example arguments:
```json
{
"from_addr": "sysadmin@neruva.io",
"to_addr": "jane@acme.test",
"subject": "R\u00e9sum\u00e9 du d\u00e9ploiement \u2014 \u5efa\u7acb",
"plain_text": "All systems operational.",
"html_text": "Your invoice is paid.
",
"attachment": {
"filename": "report.csv",
"content_type": "text/csv",
"content": "step,status\nbuild,ok\n"
},
"date": "2024-05-01T12:00:00+00:00",
"output_path": "/tmp/out.eml"
}
```
```python
def build(**kwargs):
from_addr = kwargs['from_addr']
to_addr = kwargs['to_addr']
subject = kwargs['subject']
plain_text = kwargs['plain_text']
html_text = kwargs['html_text']
attachment = kwargs['attachment']
output_path = kwargs['output_path']
date_str = kwargs.get('date')
date = None
if date_str:
date = dt.datetime.fromisoformat(date_str)
if date.tzinfo is None:
date = date.replace(tzinfo=dt.timezone.utc)
att = make_attachment(
attachment['filename'],
attachment['content_type'],
attachment['content'],
)
msg = build_email_message(
from_addr,
to_addr,
subject,
plain_text,
html_text,
attachments=[att],
date=date,
)
write_message_to_file(msg, output_path)
return output_path
```
## How to use it
make_attachment(filename, content_type, content) -> (filename, content_type, bytes)
Normalizes an attachment's content (str or bytes) into a tuple ready
for build_email_message's attachments argument.
Example: make_attachment("report.csv", "text/csv", "a,b\n1,2\n")
build_email_message(from_addr, to_addr, subject, plain_text, html_text,
attachments=None, date=None, policy=None)
-> email.message.EmailMessage
Builds a multipart/mixed message whose first part is a
multipart/alternative (text/plain + text/html, both utf-8) and whose
remaining parts are attachments (each marked Content-Disposition:
attachment). From/To/Subject/Date headers are set as given; Subject
may contain non-ASCII and will round-trip via policy.default parsing.
Example:
msg = build_email_message(
"sysadmin@neruva.io", "jane@acme.test",
"R\u00e9sum\u00e9 du d\u00e9ploiement \u2014 \u5efa\u7acb",
"All systems operational.",
"Your invoice is paid.
",
attachments=[make_attachment("report.csv", "text/csv",
"step,status\nbuild,ok\n")],
)
write_message_to_file(msg, path) -> None
Serializes msg (an EmailMessage) to RFC 5322 bytes and writes them to
the given filesystem path.
Example: write_message_to_file(msg, "/tmp/out.eml")
## Evidence (corpus named)
- held-out 16 specs, best-of-2, deepseek-chat: cold 0.312 -> 0.750 with the rung (CI +0.188..+0.688); helper reuse 1.00
- checker forged and mutation-gated, not hand-written: references accepted, every spoiler rejected, empty rejected, on 2 given specs plus 6 generated ($0.17)
- stage-1 gate before forging: 4/8 for the cheap tier cold, so the gate opened
## Files
- `scripts/skill.py`: the verified code (GET /v1/commons/rungs/rec_d0107eda77bd4c19ade8c9074df8d3ef/code)
- verify: POST /v1/commons/verify {"id": "rec_d0107eda77bd4c19ade8c9074df8d3ef"}