fable-meat-proxy 0.1.0

A passthrough Anthropic client that routes Fable inference to a human over email (a 'meat proxy').

fable-meat-proxy 🥩

A drop-in replacement for the Anthropic Python client where Fable's inference is performed by a human.

Every real model passes straight through to the genuine anthropic.Anthropic client. But when you select Fable (model="claude-fable-5" — anything containing "fable"), the proxy instead emails the prompt to your American friend, blocks while polling Gmail for their reply, and returns that reply as a normal Anthropic Message. A meat proxy: the model is a person.

flowchart LR
    A[client.messages.create] --> B{model contains<br/>'fable'?}
    B -- no --> C[real anthropic.Anthropic] --> D[API response]
    B -- yes --> E[email prompt via Gmail API] --> F[friend pastes into Fable]
    F --> G[friend replies to email] --> H[poll thread, parse reply] --> I[Message]

Install

pip install -e .          # runtime
pip install -e '.[dev]'   # + pytest

Configure

Copy .env.example to .env and fill it in:

Variable	Purpose
FABLE_FRIEND_EMAIL	Required. Where Fable prompts are sent.
FABLE_GMAIL_CREDENTIALS	OAuth client secret (Desktop app) from Google Cloud.
FABLE_GMAIL_TOKEN	Where the minted OAuth token is cached.
FABLE_REPLY_TIMEOUT_BUSINESS_DAYS	Block this many business days for a reply (default 7, weekends skipped).
FABLE_REPLY_TIMEOUT_SECONDS	Optional raw-seconds override of the deadline (tests/demos).
FABLE_POLL_INTERVAL	Seconds between Gmail polls (default 120).
ANTHROPIC_API_KEY	Standard key for the real (non-Fable) passthrough.

One-time Gmail auth

1. In Google Cloud Console, enable the Gmail API and create an OAuth client ID of type Desktop app. Download it as credentials.json.

2. Run the OAuth flow once to mint token.json:

   fable-meat-auth
   

Least-privilege scopes are requested: gmail.send + gmail.readonly (send the prompt, read the reply thread — no modify/label/delete). The minted token.json holds a refresh token, so it's a secret: it's written 0600 and gitignored.

Use

from fable_meat_proxy import Anthropic

client = Anthropic()  # config + Gmail service resolved from the environment

# Real model: ordinary API call.
client.messages.create(
    model="claude-opus-4-8", max_tokens=1024,
    messages=[{"role": "user", "content": "hi"}],
)

# Fable: emails your friend, blocks until they reply, returns their answer.
msg = client.messages.create(
    model="claude-fable-5", max_tokens=1024,
    messages=[{"role": "user", "content": "Write a haiku about meat."}],
)
print(msg.content[0].text)  # whatever your friend pasted back

Async works the same way via AsyncAnthropic (blocking Gmail calls run in a thread, polling uses asyncio.sleep):

from fable_meat_proxy import AsyncAnthropic

client = AsyncAnthropic()
msg = await client.messages.create(model="claude-fable-5", max_tokens=1024, messages=[...])

Your friend receives a formatted email (system prompt + conversation), pastes it into Fable, and replies with Fable's output as the plain-text body. The text above the quoted original is taken as the answer.

How it works

• client.py — the wrapping Anthropic / AsyncAnthropic; routes on the model name, delegates everything else (.models, .beta, messages.count_tokens, …) to the real client. Fable routing applies to messages.create / messages.stream.
• meat.py — the human backend: format → send → block on reply → build a Message.
• gmail_transport.py — OAuth, send, and thread polling, with transient-error retries (HTTP 429/5xx and network errors) using exponential backoff.
• timing.py — business-day deadline arithmetic for the (slow, human) reply timeout.
• parsing.py — render the outgoing email; extract the reply (text/plain, with an HTML fallback) and strip quoted text.
• errors.py — FableMeatError, FableReplyTimeout (also a TimeoutError), FableConfigError.

Test

pytest

43 tests run offline — they mock the Gmail service and the real Anthropic client and cover routing, sync + async paths, reply parsing (plain/HTML/quote-stripping), polling, business-day deadlines, transient-error retries, streaming rejection, delegation, config, and Message construction. The Gmail OAuth round-trip itself needs your real credentials.

Logging uses the standard logging module under the fable_meat_proxy logger (no handlers are installed by the library — configure your own to see send/poll/reply events).

Caveats

• Latency is measured in human attention span. Calls block up to 7 business days by default. The process must stay alive for the duration — for long waits, run it under a durable worker rather than an interactive script.
• Streaming for Fable raises NotImplementedError (a human reply arrives all at once).
• Tool use and token accounting are not modeled for Fable (usage is reported as zero). Non-Fable models keep the full real SDK behaviour.