Your agent doesn’t need a bigger model.

It needs faster decisions.

Jev + Hermes: routing, memory, skill picking, GUI clicks. ~0.4s, fractions of a cent.

https://t.co/KoXuXvIvLF

kerpopule/hermes-jev-skills

Source: https://github.com/kerpopule/hermes-jev-skills

Hermes Jev Skills

Give your agent a fast, cheap second brain for the small decisions.

Your agent burns frontier-model tokens on things that are not thinking: which model should answer this turn, which of 377 skills to load, which retrieved passages matter, which turns survive a summary, which button comes next. Those are decisions, not prose. Hand them to something that costs a fraction of a cent and answers in about 0.4 seconds, and let the expensive model do the writing.

That is what Jev is. It is TypeSafe’s decision model. It never writes text. You give it a state and typed questions (pick one, score this, yes or no) and it answers with a calibrated confidence. This repo wires that into an agent’s day.

jev dashboard with example data: one switch for Jev routing, every pool as a tier-by-work-kind grid, and each decision as it happens (tier, work kind, model, which pool it came from, confidence, latency).

What Jev decides, and what it costs

Eight skills ship as plain SKILL.md files, so they are not Hermes-only. The same folder works in Claude Code, Codex, or anything that reads a skill file.

Try it in two commands

git clone https://github.com/kerpopule/hermes-jev-skills ~/hermes-jev-skills && python3 ~/hermes-jev-skills/install.py

jev setup-key   # paste your key into the one-time page it opens, then run: jev doctor

The installer finds Hermes, Claude Code and Codex on the machine and installs for each one it finds. python3 install.py --check shows exactly what it would do without changing anything. --uninstall reverses it.

Not sure yet? Run jev models suggest --write to draft routing pools from price bands, then /jev routing shadow for a day. Shadow mode decides and logs without switching anything, so a day of decisions costs almost nothing and risks nothing. Turn it on when the log looks right.

On Hermes

Start in shadow mode. It is the honest way to see what Jev would do before it does anything.

/jev                         status
/jev routing shadow          decide and log, do not switch (start here)
/jev routing on              switch models per turn
/jev skills on               suggest the right skill per turn
/jev notice on               show "[Jev] hard · coding → kimi-k3 · confidence 0.92" on routed replies
/jev routing on all          make it the default for every profile (a profile's own setting still wins)

The agent gets five tools: jev_memory_filter, jev_compact_select, jev_choose_action, jev_supervise, jev_escalate.

The hermes-jev plugin uses only public plugin seams (pre_llm_call, the llm_request middleware, tools, a slash command), so hermes update does not break it and nothing in Hermes core is patched.

A plugin can swap the model, not the provider connection. On OpenRouter that still covers every vendor. If you run /model yourself, your choice wins.

Every model you have

jev models list              # everything this machine can call: price, context, vision, reasoning
jev models providers         # which providers you hold a key or login for
jev models suggest --write   # first-draft pools from price bands; then edit to taste

The catalog is models.dev, filtered to providers whose API-key name is set in your environment or Hermes .env, or that Hermes holds a login for. Only key names are read. Pools live in ~/.hermes/jev/routing.json (the default for every profile); ~/.hermes/profiles/<name>/jev/routing.json overrides it for one profile. Details in skills/jev-model-routing.

Your API key never touches the agent

jev setup-key opens a one-time page served only by your own computer. You paste your TypeSafe key there. It goes straight into the OS secret store (macOS Keychain, or secret-tool on Linux, or a 0600 file as a last resort) and, on a Hermes machine, into each profile’s .env. The agent that ran the command sees one line: stored, verified, yes or no. Never the key, not even a prefix.

The page lives on an unguessable one-time URL, refuses requests with a foreign Host header (DNS rebinding), sends no referrer, logs nothing, and shuts down after one use or ten minutes. On a headless box, run jev setup-key --tty yourself for a hidden prompt.

Do not paste your key into a chat. If you already did, make a new one.

What leaves your machine

Jev is a cloud API, so this is spelled out rather than implied:

• Routing: the user’s turn, redacted (emails, phones, tokens, long hex masked), capped at 3,000 characters. Never history, tool results, files or memory. Turns that look like they hold a secret, and any profile you list in private_profiles, send only coarse features: length, whether code is present, whether risk words appear.
• Memory: the query and up to 900 characters per passage, redacted. Your store’s ids, paths and sources are replaced with P0, P1… and never sent. A passage that looks like a credential is not sent at all.
• Compaction: up to 700 characters per turn, redacted. Turns that look sensitive are skipped.
• Skills: the turn, redacted, plus skill names and descriptions.
• Computer and browser use: the goal, short element labels, and your action descriptions. Never screenshots, page text or field values. A goal or label that looks sensitive is refused before sending.

Logs hold decisions only (tier, model, confidence, latency). Never prompt text.

Everything fails open

No key, timeout, rate limit, malformed reply, low confidence: routing keeps your current model, memory returns the original list, compaction drops nothing, skill selection suggests nothing, and computer use returns reobserve. A Jev outage costs you at most the time budget (2.5 s for routing) and never blocks a turn.

Safety rails that do not depend on Jev being right:

• Risk words (production, delete, migration, security, payment, legal…) never route to the cheapest tier.
• A large context never switches to a cheaper model mid-session.
• A transcript turn is only dropped on a confident answer.
• Jev can only ever return an action id you put in the table.

Layout

jevkit/            the library and the `jev` command (stdlib only)
skills/            eight SKILL.md skills, agent-agnostic
hermes/plugin/     the Hermes plugin
router-dashboard/  the model routing page (`jev dashboard`)
install.py         installer / uninstaller
tests/             offline tests, every Jev reply faked
docs/              integration notes and hard-won operational lessons

The tests are offline and every Jev reply is faked, so they are safe to run anywhere:

python3 -m unittest discover -s tests

License

MIT. Jev and TypeSafe are products of TypeSafe AI; this project is independent. The optional browser runner wraps browser-use/jev-ultrafast (MIT), which is not bundled.