Jev on OpenRouter: model IDs and the Decisions API

Create an OpenRouter key and call one of the Jev model IDs. OpenRouter's guide says there is no separate TypeSafe account or waitlist, and usage is billed to your OpenRouter account. You pay per input token at the price on the Jev model page, and output tokens are free. The guide gives no dollar figure of its own, so read the model page for today's price.

A request has a model, a state and a questions object. Each question is a choice (pick one option), a score (a position on an ordered scale), a noul (a yes or no probability) or a box (a rectangle around something in an image). Answers come back with probabilities and a confidence value.

• All five ways to call Jev

Use typesafe/jev-1.14 for the newest version, typesafe/jev-1.13 if you need the older one, and the alias ~typesafe/jev-latest if you want to follow TypeSafe's newest release. The alias moves when a new version ships, so pin a version ID if you tune thresholds against it. Box questions work only on typesafe/jev-1.14 and the latest alias.

The Decisions API, POST https://openrouter.ai/api/alpha/decisions, is OpenRouter's own interface for decision models, with its own TypeScript, Python and Go SDKs. The System One endpoint, POST https://openrouter.ai/api/v1/systemone, speaks TypeSafe's format, so TypeSafe's own SDKs work if you change the base URL and use your OpenRouter key.

The guide never labels the Decisions API alpha or beta, but its path contains "alpha", and it calls image input and Box early features whose format, answers and limits can change between releases. Treat both as moving parts.

The Jev Router, typesafe/jev-router, is a model ID that picks a model and a reasoning effort for each request. Jev judges the task and its difficulty, weighs the benefit of a stronger model against the estimated cost and your preferences, and the chosen model writes the reply. You can pick a cost tier, low, medium or high, and list models to prefer or exclude. It works with Chat Completions, Responses and Messages, and the response reports which model served it.

OpenRouter gives no price for the router itself, and says cost tiers are routing preferences, not a price cap. The estimated costs in its routing details are estimates, not final bills. It runs only in the global data region and cannot be combined with another router in one request.

OpenRouter's Jev guide links five. Two have figures worth knowing, both OpenRouter's own and not independently checked:

• Auto-approve coding-agent permission prompts. A hook for Claude Code, Codex, Cursor and OpenCode sends safe-looking shell commands to Jev and approves them at a score of 0.9 or more, with a fixed risk list checked first. It measured about $0.0000168 per request.
• Cut LLM cost with a Jev-verified cascade. A cheap model drafts an answer from retrieved excerpts, Jev checks that the excerpts support it, and a stronger model runs only if the check fails, with an acceptance confidence of 0.8. On 50 questions it reports zero wrong answers at $0.012, against two wrong answers at $0.175 when the stronger model answered everything. The page says the cost is about 7% of the stronger model's, and warns that results varied by two answers between runs and that thresholds should be re-checked on your own data.
• Also listed: gating agent tool calls, classifying and tagging text at scale, and classifying Reddit and YouTube comments.

• Jev in Claude Code
• Jev in OpenCode

The limits OpenRouter lists:

• Box on Jev 1.13. It returns a 400 error. Use the 1.14 ID or the latest alias.
• Images and long inputs run in long-context mode. OpenRouter says it is slower and less accurate than the normal mode. TypeSafe labels image and Box features as not ready for production.
• Box has no "not found" answer. Ask a noul question in the same request to check whether the target exists.
• The state format is not settled on the page. Its Box example sends a list with a text part and an image part, while the text describes an object. Check the Decisions API reference before relying on a plain string.