Jev (TypeSafe) judgment client

Overdeck can ask TypeSafe AI’s Jev model small, typed questions: yes/no, pick-one, or a score on a rubric. Jev is a judgment model, not a coding model. It answers questions about a piece of text and never generates text, so it cannot run an agent. It is optional and off by default.

What Jev is

Jev (“System One”) takes a state (text or JSON) and a set of named questions, and returns a calibrated answer for each one:

a Noul question returns a probability from 0 to 1 that the statement is true;
a Choice question returns a probability for each option;
a Score question returns an expected score on a rubric.

Answers typically come back in under half a second. Overdeck uses them for fuzzy judgments that are hard to do with keyword lists, such as “does this agent message end by asking a question?”.

Two routes

You can reach Jev through OpenCode Zen or directly through TypeSafe.

Route	`jev.base_url`	`jev.model`	Key
Zen route	`https://opencode.ai/zen`	`jev-1.13-free` (limited time) or `jev-1.13`	An OpenCode Zen API key
Direct route	unset (the SDK uses `https://api.typesafe.ai`)	a pinned version, for example `jev-1.13.0`	A key from console.typesafe.ai

The Zen route needs no new account if you already have an OpenCode Zen key. Both routes use the same key slot.

Configuration

Add a jev: block to ~/.overdeck/config.yaml:

jev:
  base_url: https://opencode.ai/zen   # omit for the direct route
  model: jev-1.13-free                # required; there is no default
  api_key_ref: TYPESAFE_API_KEY       # env var used when api_keys.typesafe is empty
  timeout_ms: 2000                    # per request, 1–30000

api_keys:
  typesafe: <your TypeSafe or OpenCode Zen key>

background_ai:
  cheap_mode: false
  features:
    jevTurnEndAssessment: true

You can also set the key in Settings → Background AI → TypeSafe API key (Jev). Overdeck looks for the key in this order:

api_keys.typesafe;
the environment variable named by jev.api_key_ref (default TYPESAFE_API_KEY).

There is no default model. With jev.model unset, every Jev feature reports model-not-configured and makes no request. Overdeck never falls back to the SDK’s own default model. Each Jev feature has its own toggle under background_ai.features, and all three are off by default:

jevTurnEndAssessment
jevAcceptanceCriteriaReview
jevMemoryRelevance

Low-cost mode (background_ai.cheap_mode, on by default) turns all of them off regardless of their toggles. With no jev: block, low-cost mode on, or a toggle off, Overdeck behaves exactly as it does without Jev: no request, no startup check, and no warning.

What is sent to TypeSafe

This release sends nothing: the client exists, but no feature calls it yet. When each feature ships, turning its toggle on sends the following data:

Toggle	What it sends (when that feature ships)
`jevTurnEndAssessment`	Sends an agent’s last message (trimmed to about 6,000 characters) and its role to TypeSafe to classify why the agent stopped.
`jevAcceptanceCriteriaReview`	Sends the id and text of every acceptance criterion in a plan to TypeSafe at plan finalize, for advisory warnings.
`jevMemoryRelevance`	Sends your prompt and up to 20 memory snippets (about 600 characters each) to TypeSafe to drop irrelevant memories before injection.

The same text appears under each toggle in Settings.

Privacy

On the direct route, requests go straight to TypeSafe AI. On the Zen route, they go to OpenCode Zen, which forwards them to TypeSafe. TypeSafe states that it does not train on customer data. Zero data retention is available only on TypeSafe’s enterprise plan. Overdeck never logs the API key or the request body. The client pins the SDK log level to warn, which also overrides a TYPESAFE_LOG_LEVEL=debug environment variable.

Cost

Jev costs

0.042 per million input tokens, and output is free. `jev-1.13-free` records

0. Every real request (not a repeat served from Overdeck’s in-process memo) appends one event to the cost ledger with the source background:<feature>, for example background:jevTurnEndAssessment. The 24-hour spend appears next to each toggle in Settings → Background AI.

​Jev (TypeSafe) judgment client

​What Jev is

​Two routes

​Configuration

​What is sent to TypeSafe

​Privacy

​Cost