DraftMachine — Gmail Mail Merge via CLI#

DraftMachine creates Gmail drafts from a CSV list + Markdown template. Drafts land in the user's Gmail Drafts folder for review before sending — nothing gets sent automatically.

Step 1 — Check installation#

bash

draftmachine --version

If the command is not found, install it:

bash

pip install draftmachine

Step 2 — Check Gmail credentials#

Two files must exist:

FilePurpose~/.draftmachine/client_secret.jsonOAuth app credential downloaded from Google Cloud Console~/.draftmachine/creds.jsonCached OAuth token (created automatically by draftmachine setup)

Check for them:

bash

ls ~/.draftmachine/

If client_secret.json is missing — walk the user through GCP setup#

Tell the user they need to do a one-time setup to connect DraftMachine to their Gmail:

1. Go to Google Cloud Console and create a project (or pick an existing one).

2. Navigate to APIs & Services → Enable APIs & Services and enable the Gmail API.

3. Go to APIs & Services → Credentials → Create Credentials → OAuth client ID.

4. Choose Desktop app as the application type.

5. Click Download JSON and save the file to ~/.draftmachine/client_secret.json.

   • You may need to mkdir ~/.draftmachine first.

6. Run draftmachine setup — this opens a browser window, asks for Gmail permission (draft-only scope), and saves the token.

If client_secret.json exists but creds.json is missing#

Run draftmachine setup to complete the OAuth consent flow.

If both files exist#

Credentials are ready — skip to Step 3.

Step 3 — Gather the recipient list and compose the template#

CSV file#

The CSV needs at minimum an email column (default column name: email). Any other columns become available as template variables. Ask the user what data they have. If they paste data in the conversation, write it to a .csv file.

Example:

csv

email,first_name,company
jane@example.com,Jane,Acme Corp
bob@example.com,Bob,

Markdown template#

The template is a .md file with a YAML frontmatter block for the subject line and a Markdown body using Jinja2 syntax. Ask the user what the email should say, then write the template.

markdown

---
subject: "Quick note for {{ first_name }}"
---
Hi {{ first_name }},

{% if company %}
I came across {{ company }} and thought you might find this useful.
{% endif %}

[Body of the message here]

Best,
[Sender name]

Tips for good templates:

• Use {{ variable }} to insert CSV column values.
• Wrap optional content in {% if variable %}...{% endif %} so missing values don't cause awkward blanks.
• The subject line supports Jinja2 too.
• Filters like {{ first_name | title }} and loops are supported.

Step 4 — Preview before creating drafts#

Always run --preview first. It renders the first row only to the terminal — no API calls, no drafts created. This is a fast sanity check for template errors and formatting.

bash

draftmachine send list.csv template.md --preview

If the rendered output looks right, proceed. If there are errors (undefined variables, broken conditionals, etc.), fix the template and re-preview.

Step 5 — Create the drafts#

Once the preview looks good:

bash

draftmachine send list.csv template.md

If the email address is in a column other than email, use --to-column:

bash

draftmachine send list.csv template.md --to-column work_email

DraftMachine uses a two-pass strategy: it renders all rows first (aborting early if any row has template errors), then creates all drafts via the Gmail API. This means it's all-or-nothing per run — no partial draft batches on template errors.

Step 6 — Report back#

After the command completes, tell the user:

• How many drafts were created.
• That the drafts are in their Gmail Drafts folder, ready to review and send.
• A reminder to check for any rows that were skipped (DraftMachine warns about empty/missing to addresses in the terminal output).

Error reference#

ErrorFixcommand not found: draftmachine``pip install draftmachine``No such file: client_secret.jsonComplete GCP + OAuth setup (Step 2)403 ForbiddenOAuth token lacks correct scope — re-run draftmachine setup``429 Too Many RequestsGmail API rate limit hit; DraftMachine retries 3× with backoff. If it persists, wait and re-runUndefinedError: '...' is undefinedCSV column name in template doesn't match actual column headerPartial drafts on 429No resume; re-run the full command after a short wait (may create duplicates — delete extra drafts)