Catcher

Catching the field

The skill for building catcher.json pieces. On the left, Jev is the fielder guarding the outfield: balls pop up at random spots and fall, and every tick Jev reads the glove's position and the next ball's landing spot and slides the glove to catch it. A catch needs the glove under the ball when it lands within reach of the landing spot; otherwise the ball drops.

The difficulty falls to two dials:

• fallTicks — how many ticks a ball takes to come down. This is the main dial. Fewer ticks means the ball drops faster, leaving Jev less time to cross the field — so at low fallTicks Jev physically can't get there in time and the drops pile up.
• gloveReach — how close the glove must be to the landing spot to make the catch (the reach radius). Tighter reach means Jev has to be precise, not just near.

Crank fallTicks down (or shrink gloveReach) and Jev's glove can't keep up and it leaks balls; the honest physical slew limit is the difficulty, not random noise. This is the general recipe for this harness: make the ball fall too fast to chase, and Jev's misses read as Jev's limit.

Craft

• Curate a catching mood. Default fallTicks ~`10(reach1.6) is crisp and frequently clean. Drop fallTicksto7and Jev leaks; to5or below it's a rain of drops. RaisefallTicksto13+` for a leisurely, near-perfect session.
• Tension by reach. A tight gloveReach (0.5, say) makes Jev read the landing spot exactly — it starts to miss when the ball comes in hot. A wide one is forgiving.
• Write a distinct style line. "Read the sound off the bat and burst to the spot" plays very differently from "glide, don't sprint — always keep some glide in reserve." Jev will visibly field differently.

Do NOT just ship the template. Every catcher.json you publish should be its own session with a deliberate, testable difficulty.

Validate with node "$JEV_DSH/toolchain/check.mjs". The real test is the fielding: does Jev catch the full session at a calm fall, and leak when you speed the falls up — or does it never leak (dull) or leak even on a slow pop (bad)? Either extreme is a finding to report, not a bug to mask.

Rules

• Keep catcher.json valid JSON always. A bad edit freezes the session on the last good state. You can change fallTicks/gloveReach/fieldWidth/balls live — the viewer rebuilds the field for the new profile.
• Keep title, description and style truthful — and never present this as real baseball, real stats, or real coaching.
• The catcher viewer writes .harness/verdict.json itself (caught, dropped, whether the session was clean). Do not edit it.
• This is a demo. The field, the pop flies and the timing are made up — never present this as a real game or real fielding advice.

Definition of done

• A valid catcher.json that parses and passes toolchain/check.mjs.
• A real fielding loop: Jev reads the landing spot, slides to it, catches the slow ones, and leaks them once the falls are too fast.
• The fall and reach actually shape the session — report it if Jev never drops, or drops no matter what.