Two heroes. One dungeon. Only one remembers.

Both heroes are steered by the same Jers engine through the same API, one question per room: “Which exit should the hero take?”. The left hero calls it without memory: every call starts from zero, the way stateless decision APIs work. The right hero names a subject, so Jers remembers what happened to it.

API calls 0 · spent $0.00000 · last decision –
∅

Stateless hero

Sends state + questions. No subject, no memory: the same room gives the same answer, run after run.

Runs 0Deaths 0Treasures 0
Waiting for the first move.
Nothing to teach here: a stateless call cannot carry what happened last time.
J

Jers hero, with memory

Also sends "subject": "dungeon-hero". After a death the game writes one line to that memory, and Jers recalls it the next time the hero stands in that room.

Runs 0Deaths 0Treasures 0
Waiting for the first move.

What Jers remembers about dungeon-hero

    Nothing yet. The hero has not died, and nobody has taught it anything.

    The API calls, as sent

    Stateless hero: last POST /v1/systemone

    No call yet.

    Jers hero: last POST /v1/systemone (subject and memory highlighted)

    No call yet.

    How it works

    1. In each room the game sends the room's text and one choice question to the Jers API. The engine answers with a probability for each exit. Nothing is scripted: the hero walks where the answer points.
    2. The traps are baited: a golden glow, a golden handle, gold coins. On its own the engine walks into them. Without memory it gives the old bridge 94%, so the stateless hero takes it and dies there every run.
    3. When the Jers hero dies, the game writes one line to its memory, for example The hero died in the Stone Hall. Next time there, the hero goes along a dark muddy path…. On the next run Jers recalls the line about the room the hero stands in and reads it first.
    4. The white marks on the Jers hero's bars show what the same call answers without memory ("compare": true). Teach a line and the hero uses it at once. Forget it and the hero is back to its first guess.

    Live numbers from the Jers engine (jers-english) on this machine. Measured on 2026-09-23: without memory, old bridge 94%, red door 75%, gold coins 83%. With the line for the room: muddy path 70%, green door 81%, plain stair 64%. Recall uses min_share: 0.5, so only the lines about the current room are read; with every line read, lines about other rooms could pull the Coin Hall answer back to the coins. A line that names the trap instead of the way pulls the hero toward the trap: with Never walk along the corridor with the gold coins. in its memory the hero took the coins at 94%, against 83% with no memory at all. Jers warns when such a line is written.