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. The profiles, paths and decisions shown are a demo home; the pools are a real working set. 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

| Skill | What Jev decides | Measured | |---|---|---| | Model routing | Which model is good enough for this turn, from every model you can call | ~0.4 s per turn | | Memory | Which retrieved passages are worth reading, and which contain hidden instructions | 60 passages per request, up to 480 per call; an injection screen runs locally even when Jev is down | | Handoffs | Nothing, by default. We measured it: a handoff written from Jev's keep / summarize / drop digest recalled less than one written from the plain transcript. What ships is the whole dialogue, 1,200 words and a way back to the old session | 58.7% recall alone, 75.0% with one search, against 37.5% and 68.3% before (scorecard) | | Choosing turns | Which turns to keep when a transcript must be cut to a fixed size | 71 turns in 0.95 s; beat choosing by recency 11 questions to 4 | | Skill selection | Which installed skill this turn needs, or none | 377 skills in ~2.8 s; acknowledgements answered locally for free | | Triage | How urgent a message is, what kind it is, and whether a person must see it | ~0.4 s per message, $0.00006 | | Computer use | The next GUI action, from a table of actions you already judged safe. --plan splits a multi-step command once, up front | ~0.5 s per decision | | Browser use | The next page action, same contract | ~0.4 s per step |

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

Python 3.9 or newer, no dependencies. Got it as a zip? Unzip it anywhere and run python3 install.py from that folder. Or point your agent at this repo and say "install Hermes Jev Skills": it will follow AGENTS.md.

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

Built for Hermes. The dashboard has its own notes in router-dashboard/README.md.

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//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.
• Choosing turns (jev compact-select, or handoffs with HANDOFF_JEV=1): the first and last 350 characters of each turn, redacted. Turns that look sensitive are skipped. A default handoff sends Jev nothing.
• 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
evals/             measurements you can rerun on your own sessions
docs/              integration notes and hard-won operational lessons

| Doc | Read it when | |---|---| | turning-a-jev-feature-on.md | Before you enable anything. Shadow mode, silent defaults, why a quiet log proves nothing, and bounding by the clock rather than the count. | | measuring-a-router.md | Replaying routing against your own traffic before you trust the savings. | | wiring-triage-into-a-live-pipeline.md | Adding classification to something already carrying real traffic. | | hermes-compaction.md | Handoffs on Hermes: what we measured, what ships, and the two search calls that make a handoff enough. | | response-caches.md | Before you put a response cache in front of an agent. Why it does little for a Jev loop, and the plan cache we built instead. | | evals/compaction | Measuring handoffs on your own sessions. |

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.