Agents that run on Jev instead of screenshots: Browser Use, Playwright and Stagehand builds, each with the speed and cost its author reported.
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Ricker
@0xRicker
Jev Engineering turns a static agent workflow into a graph that can rewrite itself while running.
the video is basically the problem at scale:
hundreds of routes
→ thousands of crossings
→ different agents
→ different tools
→ different confidence levels
Jev Engineering doesn’t control every step.
it controls the crossings.
when two paths compete:
→ score both
→ kill the weak route
→ reroute the task
so instead of one fixed chain, you get a live braid:
state
→ decision → parallel paths → crossings → Jev → next state
that’s the point of Jev Engineering:
more parallel execution without letting the system lose the objective.
the agents create the paths.
Jev decides which paths survive.
full breakdown below ↓
Jev is the semantic if in your agent loop.
LLM writes. Jev (TypeSafe System One) answers typed questions on the same state (Noul, Choice, Score) with calibrated probs. Your code branches.
Pull the cheap decisions out of the LLM. Early access: console.typesafe.ai
Laya fine-tuned into the decision head of a browser agent.
Ccklxx
100% (54/54)
David K 🎹
@DavidKPiano
I mixed Jev + an espresso (state) machine.
Turns out, Jev's a pretty good barista ☕
Introducing Jevspresso: XState determines what's possible, Jev decides the next move. Order in plain language, or break stuff and watch Jev cope.
Try it: jevspresso.dev
I built a data analyst agent with Jev as the review layer!
Qwen handles the main agent work, Jev acts as the review layer, and Vercel eve runs the agent loop, tool execution, and human approval flow.
The agent takes a plain-English question about the data, inspects the database schema, writes the SQL, runs the query, and explains the result.
The interesting part is what happens around that main loop.
Qwen is responsible for generating the SQL and the final answer, while Jev reviews the parts where semantic judgment is actually useful. Anything that can be checked reliably with code stays deterministic.
Jev reviews the agent at three points:
- Before the agent starts, it checks whether the user's question is clear enough to answer from the available data.
- After Qwen generates the SQL, it checks whether the query actually represents what the user asked.
- After the query runs, it checks whether the final explanation is grounded in the returned rows.
For example, we tested it with:
“Who is our best customer?”
The question sounds simple, but “best” could mean highest revenue, most purchases, highest average order value, or something else.
Instead of letting Qwen silently choose a metric, Jev flagged the question as ambiguous and asked for clarification.
The same separation applies to SQL execution.
Qwen can propose a query, but it cannot decide whether that query is safe to run. The tool accepts only a single read-only `SELECT`, SQLite runs in read-only mode, results are capped at 200 rows, and queries without a `WHERE` clause can require human approval before execution.
Those checks do not need another model call.
But a query can be completely safe and still answer the wrong question.
A deterministic rule can verify that the SQL is read-only. It cannot reliably judge whether a query for “revenue last month” accidentally calculates revenue across all time.
That is where Jev comes in.
It reviews the proposed SQL against the original question and schema before execution. After the rows come back and Qwen writes the explanation, Jev reviews that answer again to check whether the claims are actually supported by the returned data.
The project uses a local SQLite sales database, Qwen through the Vercel AI Gateway, Gradio for the interface, and only two database tools: "inspect_schema" and "run_sql".
No single model is responsible for everything. Qwen generates, Jev reviews, deterministic code controls execution, and Vercel eve manages the agent loop and approval flow.
GitHub Repo: https://github.com/Sumanth077/Hands-On-AI-Engineering/tree/main/ai_agents/nl_data_analyst_agent
100% open source.
2 AI colleagues just booked us a demo off someone's random post online
Ava and Owen are the two agents running our prospecting in @Parall_HQ.
they live in our @Parall_HQ workspace like everyone else on the sales team, and @typesafeai Jev makes the quick judgement calls for them
> Jev reads every post, Ava wakes up only for the ones that fit us
> Jev rates every account, Ava only works the best ones
> Owen writes the email, our human AE approves
> Jev sorts the replies, Owen only chases the interested ones
you don’t need to hand them leads. jevable makes it possible for proactive agents to own a job at 86% less cost than agents that check in every 30 min