agentic-letters（Agent 信件）

AgenticLetters

Send physical letters anywhere in Germany via the agentic-letters.com API. Your PDF gets printed, put in an envelope, and mailed — one API call, one real letter.

When to use

• User wants to send a physical letter, cancellation, or legal notice
• User needs to mail a document (PDF) to a German address
• User says "send a letter", "Kündigung schicken", "Brief versenden" or something similar
• User wants to mail a DSGVO request, cancellation, complaint, or greeting card

Setup

mkdir -p ~/.openclaw/secrets
echo 'AGENTIC_LETTERS_API_KEY=al_your_api_key' > ~/.openclaw/secrets/agentic_letters.env

Getting an API key

AgenticLetters has no account system and no login. The flow is:

1. Go to https://agentic-letters.com/buy
2. Enter an email address and pick a credit package
3. Pay via Stripe (card)
4. The API key (starts with al_) is sent to that email immediately

The key is a Bearer token used in every request. If the user buys more credits later with the same email, the existing key gets topped up — no new key issued. If the user doesn't have a key yet, guide them to https://agentic-letters.com/buy.

Tool

{baseDir}/agentic_letters.py — a zero-dependency Python CLI (stdlib only).

Send a letter

1. Generate an A4 PDF (max 3 pages, max 10 MB, black & white print)
2. Run the tool:

python3 {baseDir}/agentic_letters.py send \
  --pdf letter.pdf \
  --name "Max Mustermann" \
  --street "Musterstraße 1" \
  --zip 10115 \
  --city Berlin \
  --label "Kündigung Fitnessstudio"

Optional flags:

• --type <type> — letter type (default: standard). New types will be added over time; the API rejects unknown types with a list of valid ones.
• --country <code> — country code (default: DE). Currently only Germany is supported.

Output (JSON to stdout):

{
  "id": "550e8400-e29b-41d4-a716",
  "status": "queued",
  "type": "standard",
  "label": "Kündigung Fitnessstudio",
  "created_at": "2026-02-24T19:00:00Z",
  "credits_remaining": 4
}

Check letter status

python3 {baseDir}/agentic_letters.py status <letter-id>

Status values: queued → printed → sent → returned

Check remaining credits

python3 {baseDir}/agentic_letters.py credits

List all letters

python3 {baseDir}/agentic_letters.py list

Local records

Every sent letter is tracked locally in {baseDir}/records/. Each file is named YYYY-MM-DD_<id-prefix>.json and contains:

{
  "id": "550e8400-...",
  "status": "queued",
  "type": "standard",
  "label": "Kündigung Fitnessstudio",
  "recipient": { "name": "Max Mustermann", "street": "Musterstraße 1", "zip": "10115", "city": "Berlin", "country": "DE" },
  "created_at": "2026-02-24T19:00:00Z",
  "credits_remaining": 4,
  "last_checked": null
}

Records are created automatically on send and updated on status. The date prefix lets agents quickly find recent letters without scanning old files. To check on pending letters, look at recent record files and call status for any that aren't sent yet.

Generating PDFs

If the user doesn't have a PDF ready, generate one:

• pandoc for markdown → PDF: echo "Dear Sir..." | pandoc -o letter.pdf
• wkhtmltopdf for HTML → PDF: wkhtmltopdf letter.html letter.pdf
• Python with fpdf2 or reportlab for programmatic generation

Always ensure A4 format (210 × 297 mm) with at least 15 mm margins.

Error handling

Errors go to stderr with a clear origin tag. The exit code is non-zero on failure.

Origins:

• [local] — problem before the request (missing file, no API key)
• [server] — the API rejected the request (includes error code, HTTP status, detail, and field)
• [network] — could not reach the API (DNS, timeout, connection refused)

Example server error:

[server] Invalid German postal code
  code: recipient_zip_invalid
  http_status: 400
  detail: Expected a 5-digit German PLZ (e.g. "10115"), got "123".
  field: recipient.zip

On success, JSON is printed to stdout. On failure, nothing goes to stdout.

Important constraints

• Germany only — recipient must have a German address
• Max 3 pages — longer PDFs are rejected by the server
• Max 10 MB — compress images if needed
• Black & white — images are printed in grayscale
• 1 credit = 1 letter — check credits before sending
• A4 format — ensure correct page size
• Do not validate the PDF locally — the server handles all PDF validation

Typical workflows

Kündigung (cancellation): Ask for: service name, customer number, recipient address. Generate a formal cancellation letter as PDF, send it.

DSGVO Auskunftsersuchen (data access request): Ask for: company name, address, user's full name. Generate a DSGVO Art. 15 request letter, send it.

Widerspruch (objection/appeal): Ask for: authority/company, reference number, reason. Generate a formal objection letter, send it.