TypeSafe System One API for Elixir

An Elixir client for TypeSafe's System One API, the API behind Jev. It is unofficial and not published by TypeSafe. Its behaviour follows the official Python SDK:

• the same environment variables and defaults
• the same retry policy
• the same error classes

System One models don't generate text. You send some state and a map of typed questions, and get back one typed answer per question, with probabilities your code acts on.

client = TypeSafe.new()   # reads TYPESAFE_API_KEY

{:ok, response} =
  TypeSafe.system_one(client, %{ticket: "I was charged twice. Please fix this ASAP."}, %{
    billing: TypeSafe.noul("Is this ticket about billing?"),
    tone: TypeSafe.choice("What is the customer's tone?", [:calm, :frustrated, :angry]),
    urgency: TypeSafe.score("How urgent is this ticket?", ["Can wait", "This week", "Today"])
  })

response.answers
#=> %{
#     billing: %TypeSafe.NoulAnswer{noul: 0.99},
#     tone: %TypeSafe.ChoiceAnswer{
#       choice: :frustrated,
#       probabilities: %{calm: 0.0, frustrated: 0.86, angry: 0.14},
#       confidence: 0.78
#     },
#     urgency: %TypeSafe.ScoreAnswer{
#       score: 1.99,
#       legend: %{0 => "Can wait", 1 => "This week", 2 => "Today"},
#       probabilities: %{0 => 0.0, 1 => 0.0, 2 => 1.0},
#       confidence: 0.99
#     }
#   }

response.model   #=> "jev-1.13.0"
response.usage   #=> %{input_tokens: 367, output_tokens: 75}

That is a real response from jev-1.13.0.

Installation

def deps do
  [{:typesafe_ex, "~> 0.1"}]
end

It depends on req, jason and telemetry.

Questions and answers

Builder	Asks	Answer struct
TypeSafe.noul/2	whether a condition holds	NoulAnswer: noul, the probability of yes
TypeSafe.choice/2	which one of a defined set	ChoiceAnswer: choice, probabilities, confidence
TypeSafe.score/2	how far along ordered levels	ScoreAnswer: score, legend, probabilities, confidence

A few details keep answers easy to use from Elixir:

• Answers use the question's keys. Answers come back under the ids the questions used, so atom ids allow response.answers.team.
• Choice options keep their type and order. An atom option comes back as the atom. Options are sent in the order you gave, since the order is part of what the model reads.
• Score keys are integers. Level indexes in legend and probabilities are integers, not the strings on the wire.
• Helpers:
  • ChoiceAnswer.ranked/1 gives options by probability, useful for a "did you mean" prompt.
  • ScoreAnswer.normalized/1 scales the score to 0..1.
  • ScoreAnswer.level/1 gives the most probable level.
  • NoulAnswer.yes?/2 compares the probability to a threshold.

TypeSafe.choice("Which team should own this ticket?",
  billing: "Charges, invoices, refunds",
  technical: "Bugs, outages, integrations",
  unclear: "The ticket does not say enough to tell"
)

TypeSafe.noul("If the user wants to change the lights, do they want them on?",
  true: "Lights on or brighter",
  false: "Lights off or dimmer"
)

Instructions and descriptions can be maps or lists when structure makes a question clearer. A raw map (%{"type" => ..., ...}) is sent as given, and its answer comes back raw. That covers question types this client predates.

Code owns the decision

Ask independent questions together: they share one read of the state and run in parallel. Then let ordinary code apply the policy.

%{team: team, security: security} = response.answers

cond do
  TypeSafe.NoulAnswer.yes?(security) -> {:route, :security}
  team.choice == :unclear or team.confidence < 0.5 -> {:route, :human}
  true -> {:route, team.choice}
end

confidence measures how concentrated the distribution is. It is not the probability that the answer is right. Tune thresholds on your own data, and pin a versioned model such as "jev-1.13.0" once you have. jev-latest moves when a new release ships.

For many items, run one call per item concurrently:

tickets
|> Task.async_stream(&TypeSafe.system_one(client, %{ticket: &1}, questions), max_concurrency: 8)
|> Enum.map(fn {:ok, result} -> result end)

Configuration

Option to new/1	Environment variable	Default
:api_key	TYPESAFE_API_KEY	none
:base_url	TYPESAFE_BASE_URL	https://api.typesafe.ai
:model	TYPESAFE_DEFAULT_MODEL	jev-latest
:timeout		10_000 ms per response
:retry		see below
:headers		extra request headers
:req_options		merged into the Req request last

A missing key doesn't stop new/1, so an app can boot without one. Calls then return {:error, %TypeSafe.Error{reason: :no_api_key}} without making a request. TypeSafe.configured?/1 tells you which case you are in.

system_one/4 can override :model, :timeout, :retry and :headers per call. It also takes :extra_body for top-level fields the API adds later.

Errors and retries

Failures return {:error, %TypeSafe.Error{}}, and system_one!/4 raises the same struct. Each error has a reason, the HTTP status, the server's message, and the x-typesafe-request-id as request_id.

reason	When
:no_api_key	no key configured; no request made
:bad_request, :authentication, :permission_denied, :not_found	400, 401, 403, 404
:unprocessable_entity	422; the message lists each field, as path: problem
:rate_limited, :overloaded, :server_error, :http_error	429, 529, other 5xx, anything else
:timeout, :connection	no response
:invalid_response	a 2xx missing a required field; the message names it

Retries follow the official SDKs:

• What is retried: up to 2 retries on 408, 429 and every 5xx, and on timeouts and failed connections.
• Backoff: from 500 ms, doubling to 5 s, with 25% jitter.
• Server waits: retry-after-ms and retry-after are honoured.
• Budget: 30 s per call, including waits. A retry whose wait would pass the budget is not attempted.
• Retry count: each retry sends x-typesafe-retry-count.

Configure it with retry: [max_retries: 5, budget: 60_000], or turn it off with retry: false, on the client or per call. See TypeSafe.Retry for the options.

Telemetry

Every request runs in a :telemetry.span/3 named [:typesafe, :request].

• Metadata: method, path and model.
• On stop: result (:ok or :error), request_id, and, on error, reason and status.

Testing an app that uses it

Point the client at Req.Test:

# config/test.exs
config :my_app, :typesafe, req_options: [plug: {Req.Test, MyApp.TypeSafe}]

# in a test
Req.Test.stub(MyApp.TypeSafe, fn conn ->
  Req.Test.json(conn, %{
    "model" => "jev-1.13.0",
    "answers" => %{"billing" => %{"type" => "noul", "noul" => 0.97}},
    "usage" => %{"input_tokens" => 100, "output_tokens" => 10}
  })
end)

Developing

mix test                                         # unit tests, no network
TYPESAFE_API_KEY=... mix test --include integration   # also calls the live API

TypeSafe docs: index · primitives · confidence · HTTP API

License

MIT. See LICENSE.