slaguru666andClaude Opus 5 2c547efe72 simulate: a lethality harness that uses the real rules
THROUGH TRAIN publishes "MEASURED, 400 runs each" and a 24% wipe rate; the starter
publishes its own table. Nothing in this repository could produce either number, so both
were claims rather than results and neither could be re-checked after a rule moved.

The harness knows no rules of its own. Everything comes out of rules.mjs, because a
harness with its own copy of the combat loop measures a game nobody is playing and
drifts silently the first time a rule changes. Two things had to move for that to be
possible:

  applyDifficulty, resolveBands and gradeRoll -> rules.mjs. The whole of d100 resolution
  lived in ringbrp.mjs, which node cannot import. All three are pure, so they moved and
  the engine re-exports them; no caller changes. check-rules then refused them for having
  no spot-check, so they now have fifteen, covering the 1% floor, the 96-99 rule and
  00-always-fumbles. They had none in their entire life inside the engine.

  expandFromRegister -> tools/expand-spec.mjs. A roster agent is written as a job and a
  rank and carries no skills or kit; everything it can do is derived at build time by a
  function locked inside build-packs.mjs, which cannot be imported because importing it
  runs the build. A simulated agent expanded by a second copy of that logic is not the
  agent that gets packed. Moved verbatim; both sides import one copy.

Deterministic throughout: same creature, party and seed, same numbers, which is what
lets a published table be verified rather than remembered.

What it finds: for the Act Three standoff the seed barely matters (0.5-2.8% wipe across
five seeds, eight rounds throughout) and party composition dominates everything. Four
support agents against the six miners wipe 92.8% of the time; swap in the heavy and the
warden and it is 0.3%. The published 24% is not a property of the encounter, and no
single figure can be.

Models Reaction re-rolled each round, banding, graded defences, the stacking defence
penalty, damage by band, major wounds and the dying clock. Does NOT yet model hit
locations, bleeding, panic, cover, range bands or fire modes, all of which make a losing
fight worse. Read the output as a floor, never a ceiling.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-30 21:10:05 +01:00
2026-08-30 21:08:36 +01:00
2026-08-30 21:08:22 +01:00

THE CUSTODIANS

A Basic Roleplaying game of crossings, as a Foundry VTT system.

A drab British government agency deals with crossings. Reality keeps a record of what belongs where, and it can be made to get it wrong. Agents are civil servants: they carry warrant cards and cordon tape, they file in triplicate, and the thing that makes them dangerous is that they know how the record works.

The tone is bureaucratic horror. Most cases close with an arrangement rather than a fight, and the supernatural is a filing error somebody committed on purpose.


Installing

In Foundry: Game Systems → Install System → Manifest URL

https://gitea.timevans.uk/slaguru666/RingBRP/raw/branch/main/system.json

Or by hand: clone this repository into your Foundry data directory as Data/systems/ringbrp, then restart Foundry.

git clone https://gitea.timevans.uk/slaguru666/RingBRP.git ringbrp

Requires Foundry v13+ (verified against v14.364). No modules are required. Dice So Nice works if you have it, using your own dice — the system ships no dice skins and does not touch anybody's dice settings.

Deploying to a remote Foundry server

The built compendia in packs/ are committed on purpose, so a remote server needs nothing but the files:

cd /path/to/foundrydata/Data/systems
git clone https://gitea.timevans.uk/slaguru666/RingBRP.git ringbrp
# restart Foundry

node_modules/ is not committed. You only need it if you intend to rebuild the packs or regenerate art on that machine:

npm install          # pulls classic-level, used to write the LevelDB packs
npm run build        # rebuilds packs/ from tools/content.mjs
npm run check        # the five guards; the build refuses to run if they fail

To update a deployed server: git pull and restart Foundry. If the pull touches packs/, Foundry must be stopped first — LevelDB will not tolerate its files changing underneath a running server.


What is in the box

Postings 25, each with a key characteristic, trained skills, talents and its own kit
Trades 10 ordinary jobs the department recruits from, plus induction
Catalogue 236 items — 123 gear, 62 weapons, 32 armour, 19 vehicles
Skills / talents 62 skills, 19 talents
Bestiary 21 statblocks across folklore, horror and the far side
Eras modern, antique, future, anomalous — the agency is old and never abolishes anything
Icons 292, all generated from tools/icons.mjs; no external art
Starter scenario BLACK PLATFORM, a six-player action starter, importable as a single Adventure
Compendia pregens, NPCs, skills, weapons, armour, gear, vehicles, powers, tables, rules, the starter
Rules journal 13 pages, generated from rules.mjs so the book cannot drift from the code

The rules, in brief

d100 roll-under, banding into critical / special / success / failure / fumble. 96–99 always fail, 00 always fumbles, and every skill has a 1% floor.

Reaction Lanes replace Strike Rank. Initiative is 3 × max(⌈DEX/3⌉, ⌈readiness/10⌉) less carried load, plus a d6, re-rolled every round — including the first, so the opening round is ordered like every other.

Coherence runs 10 → 0 and measures how well-filed an agent is in reality. It bands into Anchored / Loose / Adrift / Unmoored / Displaced, and spending it is how the supernatural works.

The Quiet Arts are deliberate misfilings, not spells. They cost Coherence, and they only ever arrive from a crossing that goes wrong.

Defences are graded. A defence stops a blow of its own quality or worse outright; against something better it only reduces it by as many steps as it was outclassed by. Only a critical stops a critical.

Access is a record. There is no hacking skill and nothing to break into — see below.

A weapon's fire mode is a decision. Slow weapons shoot better and then make you work; fast ones offer a second shot at the cost of both; rapid ones fire bursts; beams can be held on the target for damage instead of hits. A weapon that cannot fire a burst cannot be made to.

Sights and lamps apply themselves. A sight is graded by range band — a telescopic sight is a penalty inside ten metres — and a carried lamp buys the dark back to dim, never to daylight, and tells everyone where you are. Neither is a thing the player selects: both are facts about what is in the pack.


Borrowed Authority — the access subsystem

Deliberately not cyberpunk. Nobody jacks into anything.

What an agent has is a named credential belonging to somebody real, with a scope of things that person could plausibly do, a Trust that erodes as it is used, and red flags describing how the real owner behaves.

  • Inside its scope there is no roll. A facilities contractor opening a plant room is not intrusion, it is Tuesday. It costs 1 Trust and it works.
  • One tier beyond is a stretch — roll, at −20 for each red flag you break. The system is not testing whether you are clever. It is testing whether you are behaving like the person whose name is on the record.
  • Two tiers beyond is impossible at any skill. No percentage on any sheet gets a contractor issuing accounts.
  • A fumble burns the credential, and somebody real is going to be asked about it.

A credential is assembled, not found: up to three dossier items, each a separate scene using a different skill, at most one of them at a keyboard. Items make the credential better, never the roll easier.

AI is a posture on the target rather than an opponent — a gatekeeper raises what counts as routine, an analyst writes a new red flag every time you stretch, an asset stands in for a dossier item.

And you may spend Coherence to widen a scope, because reality can be made to remember that the person always held that duty. It works. It always works. Push a credential past what its Trust will carry and your file and theirs converge one step, and nothing in this game spends anything to converge them back.


Repository layout

ringbrp.mjs          the system: sheets, engine, hooks (~5,500 lines)
rules.mjs            THE SINGLE AUTHORITY for every rule formula
system.json          Foundry manifest
template.json        data model for every Actor and Item type
templates/           Handlebars sheets
styles/              one stylesheet
lang/en.json         all user-facing text
icons/  fonts/  art/     generated art
packs/               built LevelDB compendia (committed — see Deploying)
tools/
  content.mjs        the catalogue: skills, weapons, armour, gear, vehicles, NPCs
  build-packs.mjs    builds packs/ — runs the five guards first and refuses on failure
  make-icons.mjs     draws all 231 icons
  rules-text.mjs     generates the rules journal FROM rules.mjs
  mission.mjs        the case generator
  mission-tables.mjs its content tables
  check-rules.mjs    guard: no rule may be defined twice
  check-kits.mjs     guard: every posting's kit must exist and be usable
  check-lang.mjs     guard: no localisation key may be both a value and a branch
docs/REVIEW_LOG.md   the design and defect log, R-1 onward

The one rule this codebase enforces on itself

No rule formula may exist in more than one place. Everything lives in rules.mjs, and tools/check-rules.mjs fails the build if a formula is restated, if an alias stops being identity-equal to what it aliases, if a constant is re-declared as a literal, or if an exported rule has no spot-check. The packs used to be built under one set of numbers and played under another; this makes that impossible to ship.

The build runs all five guards before it writes anything:

check-rules: OK — 96 rules, 22 files scanned, 3 aliases + 46 constant sets checked, 306 formulas verified
check-kits: OK — 25 roles, 10 trades, 218 catalogue items, every kit key resolves, every posting can use what it carries, every loadout distinct
check-lang: OK — en.json, 995 keys, no leaf/branch collisions
check-behaviour: OK — 67 behavioural tests
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