Ruby functions that answer questions about text

Any Enumerable goes in. Read the answer from Call#value.

Install

Channel
`gem install thinkthen`

Set THINKTHEN_API_KEY in the environment.

A first call

require "thinkthen"

question = "Which line gives the refund deadline?"
policy = [
  "Returns need the original receipt.",
  "Refunds are issued within 30 days of purchase.",
  "Shipping is free on orders over $50.",
  "Gift cards cannot be exchanged for cash."
]
refund_deadline = ThinkThen.find(question, policy).value
raise unless refund_deadline.unit == policy[1]

question = "Which labels fit this message?"
labels = ["praise", "bug", "billing"]
message =
  "Love the new dashboard, but export crashes the app,\n" \
  "and I was charged twice.\n"
fitting_labels = ThinkThen.tag(
  question, message, labels:
).value
raise unless fitting_labels == ["praise", "bug", "billing"]

Not sure comes back as nil. Branch on it and send those cases to a person. Each function page shows its Ruby call.

Run facts

Call#facts counts this call.

Errors

Every failure raises a ThinkThen::Error. Its subclass names the kind: UsageError, BackendError, LocalError, DeadlineError, DefectError or CancelledError.

Settings and recording

Engine.new takes each setting as a keyword and reads the environment for the rest. record: writes a recording to a folder. replay: answers from that recording with no connection. The Settings page lists every setting.

Jev, Liquid d1 and Ollama from Ruby

Ruby reads its backend from the environment. Set THINKTHEN_BACKEND to the name below. Set the backend's key variable in the shell, and the same sample asks that backend.

Backend	Name	Key variable
TypeSafe Jev	`typesafe`	`TYPESAFE_API_KEY`
Liquid d1	`liquid`	`LIQUIDAI_API_KEY`, then `LIQUID_API_KEY`
Ollama	`ollama`	`OLLAMA_API_KEY`. A local address needs no key.

Ask TypeSafe Jev.

export THINKTHEN_BACKEND=typesafe
export TYPESAFE_API_KEY=...

Ask Liquid d1.

export THINKTHEN_BACKEND=liquid
export LIQUIDAI_API_KEY=...

Ask Ollama. This block names a second port, 11535, as the site's runs do. On the default port, leave THINKTHEN_BASE_URL out.

export THINKTHEN_BACKEND=ollama
export THINKTHEN_BASE_URL=http://localhost:11535/v1

require "thinkthen"

question = "Does the customer ask for a refund?"
broken = "Please refund my order. It arrived broken."
thanks = "Thanks for the quick help yesterday!"
broken_is_refund = ThinkThen.decide(question, broken).value
thanks_is_refund = ThinkThen.decide(question, thanks).value
raise unless broken_is_refund == true
raise unless thanks_is_refund == false

The configuration file's backend names a default backend for every run. The Configuration page shows the file.

OpenAI Decisions API from Ruby

OpenAI announced its Decisions API on 2026-09-29 in its DevDay 2026 recap. OpenAI has published no address, schema or price, so ThinkThen cannot call it. The OpenAI Decisions API page says what ThinkThen knows.

What is different in Ruby

Any Enumerable crosses to the engine once.

On GitHub: github.com/botassembly/thinkthen