Configuration

ThinkThen sends each question and its text to a model service, which answers it and bills your account. You choose the service, the model and the key with options on each command or with THINKTHEN_ environment variables.

What you have	What to set
A TypeSafe account, or no account yet	THINKTHEN_API_KEY. This is the default.
An OpenAI account	OPENAI_API_KEY and THINKTHEN_BACKEND=openai
A gateway or a model server of your own	THINKTHEN_URL for System One or OPENAI_BASE_URL for OpenAI, plus the model and key it expects

An option on the command line wins over its variable. --backend openai on one command, for example, uses OpenAI for that command only.

Jev on System One, the default

ThinkThen asks Jev, model jev-1.13.0, through TypeSafe's System One service at https://api.typesafe.ai/v1. You need a TypeSafe account, and each call counts against it.

1. Sign in to the TypeSafe console.
2. Create a key on its keys page.
3. Set the key in your shell:

export THINKTHEN_API_KEY='your key'

ThinkThen reads this key from THINKTHEN_API_KEY and from no other variable.

To check which service and model answered, ask for the details with --json and keep the source:

echo 'Please refund my order.' |
  thinkthen decide --json \
    'Does the customer request a refund?' |
  jq -c '.source | {backend, model}'

Output

{"backend":"systemone","model":"jev-1.13.0"}
Copy

There is no config file.

OpenAI

The openai backend calls OpenAI's decisions API at https://api.openai.com/v1. Its default model is gpt-6-luna. Each call counts against your OpenAI account.

1. Create a key on your OpenAI account's API keys page.
2. Set the key, and choose OpenAI for every command in this shell:

export OPENAI_API_KEY='your key'
export THINKTHEN_BACKEND=openai

To use OpenAI for one command only, leave out THINKTHEN_BACKEND and add --backend openai to that command. To use another OpenAI model, set THINKTHEN_MODEL or add --model NAME.

Your own server

--url sends the same requests to another address, such as a gateway or a model you host. --model names the model that server should use. The server must speak the API of the backend you point at it:

Backend	Request it sends	Key it sends
systemone	POST URL/systemone	THINKTHEN_API_KEY
openai	POST URL/decisions	OPENAI_API_KEY

Each request is JSON, with the key as a bearer token in the authorization header. ThinkThen doesn't call a chat or completions endpoint.

To point System One at your server for every command in this shell:

export THINKTHEN_API_KEY='your server key'
export THINKTHEN_URL=https://models.example.com/v1
export THINKTHEN_MODEL=my-model

Three rules apply to the address:

• It must use HTTPS, or plain HTTP to localhost, 127.0.0.1 or [::1]. Any other http:// address stops with usage.url before a request is sent.
• THINKTHEN_URL sets only the System One address, taking precedence over THINKTHEN_BASE_URL. OpenAI reads OPENAI_BASE_URL. An explicit --url or SDK Settings.url overrides the address for the chosen backend, including when THINKTHEN_BACKEND chooses it.
• If your server's certificate comes from your own certificate authority, set THINKTHEN_CA_FILE to that authority's PEM file. ThinkThen trusts it as well as your system's certificates.

The source in --json names the backend and model, so the check above shows the route each answer took.

Every model setting

Option	Variable	Default
--backend NAME	THINKTHEN_BACKEND	systemone
--model MODEL	THINKTHEN_MODEL	jev-1.13.0, or gpt-6-luna for openai
--url URL	THINKTHEN_URL (System One), OPENAI_BASE_URL (OpenAI)	The backend's own address
none	THINKTHEN_API_KEY	The System One key
none	OPENAI_API_KEY	The OpenAI key
none	THINKTHEN_CA_FILE	Your system's certificates only

THINKTHEN_MODEL applies only to commands. In an SDK, set the model on your client; without an explicit model setting, it uses the chosen backend's default model.

Keys come only from these variables. Keep them in your shell or a secret manager, never in a script or a toolbox file. If the key is missing or blank, ThinkThen stops with usage.key-missing and exit code 2 before it sends anything; Troubleshooting lists that error and the others.

A bar you tuned on one model belongs to that model. If you change the model, check your bars again on your own messages.

Options lists every other setting.