slaguru666andClaude Opus 5
4cfacd47fe
I asked for this on a false premise of my own: I reported that adding a creature shifted a shared random stream and perturbed every other creature's recorded number. That is not true and the code never did it. measure() builds its own mulberry32 from the seed on every call, and check-lethality calls it once per creature, so a creature's numbers do not depend on its neighbours or its position. Measured rather than argued: inserting a creature ahead of the barghest changes 0 of 47 existing entries. The file's own claim — "the only thing that can move the number is a change to the rules or to the creature" — was accurate all along, and my last commit message says otherwise. It is wrong. The real cause, found by replaying each commit against the baseline as committed at4b71859:4b71859baseline recorded 0 of 46 differ322389bbestiary 0 of 46 differddc4f99hit locations reach combat 26 of 46 differ <-- herea90c4f3..e5dc9b526 of 46 differddc4f99routed every ordinary blow through the hit location table. That is the largest change the combat system has had and it moved 26 of 46 creatures, which is correct and expected. What is not correct is that nobody noticed for four commits: each creature moved by one or two points, the guard allowed six, and it reported OK while describing a game nobody was playing. So the tolerance goes. It exists for sampling noise and there is no sampling noise here — same party, same seed, same counts, and two recordings of unchanged code are byte-identical. Anything that moves is a real change, which is the entire point of the file. `rounds` is now compared too; it was recorded and then never read, so a creature could take a round longer to kill forever without a word. Because exactness only means something if the measurement is exact, the guard now proves it instead of assuming it: one creature measured twice must come back identical, and it says so plainly if a future change reaches for Math.random. Negative-tested. A 2% change to locationMaxHp now trips 8 creatures at +1.5 and +0.5 points of wipe rate — every one of which the old tolerance would have passed. Breaking determinism is caught and named. Also fixes update-readme, which advertised 8 guards while the build ran 9: check-anatomy was added without touching the list, which is precisely what the comment above that list already warned had happened once. The list is no longer trusted — it is checked against the `check` script in package.json, and refuses to write a README advertising a different set than the build runs. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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 eight 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 | 47 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 eight 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
check-lethality.mjs guard: no creature may quietly change what it does to a party
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 eight guards before it writes anything:
check-rules: OK — 107 rules, 34 files scanned, 3 aliases + 46 constant sets checked, 381 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, 1016 keys, no leaf/branch collisions
check-templates: OK — 19 templates compile
check-behaviour: OK — 75 behavioural tests
check-scenarios: OK — 10 scenario files, 78 mechanic tags, every skill named resolves against 62 catalogue entries
check-creatures: OK — 102 actor specs across 8 sources, every characteristic, skill, kit key, talent, species and style resolves, no duplicate keys
check-anatomy: OK — 5 body plans, 36 locations, d20 complete in both modes, every location drawn, every kind handled and destructible, 20 plan changes carried 432 wounds with their severity intact, 1 flyer(s) with a survivable landing
check-lethality: OK — 47 creatures, every one fighting exactly as recorded against the frozen party