docs(link): protocol 6 part b -- leases, participation, and what the walk found

Six files. `v6.md` gains sections 7-10: one version with two halves, the lease
plane, the participation ledger, and 11b's verification.

Three corrections to what the plan and the design of record assumed.

Phase 11b is FIVE repos, not four, and in the opposite direction from 11a's
correction: a lease's ledger row had no reconcile path anywhere, because the step
that made it names `core.lease` and that is core's own action. `website` joins.

EVENTS.md's §D frames the 258 `Config.Get` call sites as splitting into two
patterns. Measured on 57.4: of the 158 non-Bridge sites in `Scripts/`, roughly
eight are read live. The allowlist is not a curated subset of a large pool, it is
nearly the whole of what exists. And `Config.Set` has exactly one caller in the
entire tree, so on a stock shard a GM cannot drift a configuration lease even
deliberately -- which is why proving `drifted` needed a scaffolding verb.

§G's "participation attribution is now the largest piece of new UO work" closes,
and the live-config-lease row goes to built-with-one-key.

§10.1 records the defect the phase's own deferral found in 11a's shipped code:
`bridge.busy` answered 200 instead of 425 because the frame carried two `kind`
fields and parsers take the last. Unreachable in 11a by construction; produced on
the first collision here.

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
2026-09-04 19:32:11 -05:00
parent 1521c5af7e
commit eabaf2635f
6 changed files with 546 additions and 23 deletions

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@@ -69,6 +69,12 @@ Pin the version you built against and compare it to the header (or `/health.prot
**v2 (Protocol 2.0)** added the account-provisioning surface (§6.x: `POST /accounts/create`, `DELETE /link/{account}`) and the `account.*` events. Outbound event kinds are **additive** — a v1 client that ignores unknown kinds keeps working against the live feed — but the new *endpoints* require a v2 sidecar. If you send `X-UOLink-Version: 1`, calls to the new endpoints are refused with the 409 above.
**v6 (Protocol 6)** is the first bump that adds a **promise** rather than data: a command carrying
an `idempotencyKey` is executed at most once (see *Retrying a command safely* in §6). It also adds
`champ.boss.killed`, and the **event plane** — leases and the run-scoped participation ledger, six
endpoints, all of them gated on the shard by `Bridge.EventsEnabled` and answering **403** when an
operator has not switched it on. See [`v6.md`](v6.md).
**v3 (Protocol 3.0)** adds `world.ruleset`, `points.board` and `vendor.listing` /
`vendor.listing.remove`, with the `GET /ruleset`, `/points` and `/market` reads that serve them from
the sidecar's store. Same shape as the v2 bump: the event kinds are additive, so a v2 client that
@@ -970,6 +976,89 @@ human just pressed a button for and can see the result of.
The DELETE forms (`/towncrier/{id}`, `/news/{id}`) take no key: their idempotency is inherent — the
second removal of an entry is a no-op the shard is already happy to perform.
### The event plane — leases (Protocol 6)
**Off by default.** Every endpoint below answers **403** unless the operator has set
`Bridge.EventsEnabled` on the shard. That is deliberately not the admin write plane's switch:
enabling admin writes is consenting to staff moderation from a screen a human is looking at, and
enabling this is consenting to your world being changed and watched on a schedule, unattended.
A **lease** is a live configuration value held at a new setting for a bounded time. The shard
restores the baseline when the deadline passes **whether or not you are ever heard from again** —
so the worst case is a world back at baseline early, never one stuck changed indefinitely.
```json
GET /lease
→ 200 { "kind":"lease.list.ok", "leases":[
{ "key":"PlayerCaps.SkillCap", "label":"Starting skill cap", "type":"float",
"min":1000, "max":1500, "default":"1000", "current":"1000", "held":false } ] }
POST /lease
{ "key":"PlayerCaps.SkillCap", "value":"1200", "holdMs":600000,
"untilMs":1788567000000, "runId":"77", "idempotencyKey":"…" }
→ 200 { "kind":"lease.ok", "baseline":"1000", "applied":"1200", "untilMs":1788567000000 }
POST /lease/release
{ "key":"PlayerCaps.SkillCap", "expected":"1200", "baseline":"1000" }
→ 200 { "kind":"lease.ok", "released":true, "current":"1000" }
```
Five things a caller needs:
- **The catalog is an allowlist and it is short.** A shard advertises only keys it has verified take
effect. Most of ServUO's configuration is cached at type initialisation, where a lease would apply
cleanly and do nothing — the worst failure this feature has — so `lease.list` is the authority and
"any config key" is not offered.
- **`holdMs` is what the shard honours; `untilMs` is for display.** Send both. An absolute deadline
is measured against two clocks, and a shard whose clock runs fast would restore your lease the
moment it took it.
- **Values cross as text, whatever `type` says.** `"1200"`, not `1200`. Comparison is done on parsed
values at the other end; the text is so a compare-and-set is comparing what you sent.
- **`released` can answer `lease.drifted` at 200.** That means somebody moved the value while you
held it, the shard **did not overwrite them**, and `current` is what is there now. It is not an
error: the mechanism did its job, and only a human can decide what should happen next.
- **`held` means the shard still has a record of the lease, not that the value is still overridden.**
A lease whose deadline has fired stays listed with `expired: true` until you release it, so a
reconcile in that window does not read a working backstop as a lost resource. A shard restart, by
contrast, reverts every lease and clears the record — `held: false` is how you learn that.
### The event plane — participation (Protocol 6)
A run-scoped tally of who took part: presence in a declared area, plus kill credit inside it, keyed
by **character serial**. The shard computes a score and you store it; the components ride along so
you can explain it.
```json
POST /participation
{ "runId":"99", "map":"Felucca", "x":1496, "y":1628, "radius":40, "holdMs":3600000 }
→ 200 { "kind":"participation.ok", "runId":"99", "members":0, "closed":false }
POST /participation/99/snapshot
{ "idempotencyKey":"…" }
→ 200 { "kind":"participation.snapshot.ok", "runId":"99", "members":2, "killWeight":5,
"participants":[ { "serial":"0xCB20", "name":"Jarvis", "acct":"seed_001", "webId":"17",
"seconds":3600, "minutes":"60.00", "kills":3, "score":"75.0000",
"firstMs":1788550182074, "lastMs":1788553782074 } ] }
POST /participation/99/close
→ 200 { "kind":"participation.ok", "closed":true, "known":true, "members":2 }
```
- **The area is a point and a radius, not a region name.** The most specific region containing an
event is routinely anonymous on a UO map — an active champion spawn registers a nameless region
over its own area — so a region-named venue would be undeclarable for exactly the places events
happen.
- **`snapshot` is a POST for a read**, because it carries your `idempotencyKey`. On a well-attended
run the shard walks its members across game ticks rather than in one call, so a repeat arriving
mid-walk is answered **425**. Come back.
- **The tally is persisted in the world save**, so it survives a restart mid-event. `close` on a run
the shard has forgotten answers `known: false` at 200 rather than an error: nothing is being
counted for it either way.
- **`refused`** on a snapshot is the number of members the shard's cap turned away. A truncated tally
says so rather than quietly being short.
- **`webId`** is present only where the character's game account is linked to a website user. Most
characters carry none; treat its absence as ordinary.
### Help-page (support) queue
Read the open queue, respond to a player, or close a page. Staff-facing — gate behind your own
@@ -1165,7 +1254,8 @@ sidecar defines no audiences. Deciding who may see what is the consuming site's
| 200 | OK |
| 400 | Bad request (malformed body, invalid parameter, or a shard `*.error` that isn't a not-found) |
| 401 | Missing or invalid auth token |
| 404 | Not found (unknown account / character / id, or a not-linked account) |
| 403 | Refused by the operator — the admin write plane, or the event plane (`Bridge.EventsEnabled`), is switched off on the shard |
| 404 | Not found (unknown account / character / id, a not-linked account, an unoffered lease key, or a run the shard is not counting) |
| 409 | Conflict — protocol version mismatch, or an account name already taken on `POST /accounts/create` |
| 425 | Too Early — a command with this `idempotencyKey` is still in flight on the shard (Protocol 6). Nothing ran; retry |
| 429 | Too many requests — the shard's per-IP account cap was hit on `POST /accounts/create` |

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@@ -317,6 +317,41 @@ kind including ones a later protocol adds. A command with no key behaves exactly
One new outbound kind comes with it, **`bridge.busy`**: a repeat arrived while the original is still
in flight, nothing ran, come back.
### The event plane, and the Bridge's first persisted state (Protocol 6)
```jsonc
{"kind":"lease.apply","key":"PlayerCaps.SkillCap","value":"1200","holdMs":600000,"runId":"77"}
{"kind":"participation.open","runId":"99","map":"Felucca","x":1496,"y":1628,"radius":40}
```
Six commands behind one new gate, `Bridge.EventsEnabled`, default off and deliberately not the admin
write plane's switch. Two facts about ServUO shaped both halves and are worth recording here rather
than only in the spec.
**`Server/Config.cs` is a real runtime store, and almost nothing reads it live.** `Config.Set`
mutates the in-memory entry table and `Config.Load()` is guarded by `_Initialized`, so a Set survives
every later Get — but of the **158** non-Bridge `Config.Get` call sites in `Scripts/`, roughly
**eight** are read at the call site. The rest are cached at type initialisation, where a lease
applies cleanly and does nothing at all. That is why the lease catalog is a verified allowlist and
never "any config key".
Two consequences, both deliberate: **nothing calls `Config.Save()`**, so a lease never reaches disk
and a shard restart is a free restore; and **`Config.Set` has exactly one caller in the whole tree**
(`Server/ScriptCompiler.cs`), so on a stock shard no GM can drift a configuration lease even
deliberately — the compare-and-set is still required for Phase 12's object-property leases, and
proving it needs the scaffolding driver.
**The participation ledger is the first thing this plugin has ever persisted.** A run spans hours and
a restart mid-event is ordinary, so an in-memory tally would silently regress every attendee's score.
`Server.Persistence` plus `EventSink.WorldSave` writes `Saves/Bridge/Participation.bin` beside the
world save — no persistence *item*, so no world object and nothing for a GM to delete by accident.
The hooks attach in `Configure()`, because `EventSink.WorldLoad` fires inside `World.Load()` and
`Initialize()` is too late.
**And the first handler that defers.** `participation.snapshot` walks a large run's members across
Core ticks rather than in one inbound call, which makes it the first handler to complete after
`OnInboundLine` returned — and therefore the first that can actually produce `bridge.busy`.
### `server.hello` is per-connection, not per-boot
The sidecar restarts independently of the shard, so anything it needs up front must be re-sent on **every** connect. An earlier draft emitted `server.started` once at `EventSink.ServerStarted`; a sidecar that came up second never received it and had no idea which shard it was attached to.

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@@ -1,7 +1,7 @@
# Protocol 6 — A guarantee, and the kind that pays for it
**Status:** In review on `edge`. Part **a** of two: see §7 for what protocol 6 gains in 11b before it cuts over.
**Date:** 2026-09-04
**Status:** In review on `edge`. **Both halves, 11a and 11b, as one protocol version** — see §7.
**Date:** 2026-09-04 (11a), amended 2026-09-05 (11b)
**Codebase:** ServUO 57.4, `<servuo>`, net48 / x64, Expansion **EJ**.
**Companion to** [`PLAN.md`](PLAN.md) (1.0 read/event plane), [`PROTOCOL_2.md`](PROTOCOL_2.md) (2.0 provisioning + world-state streams), [`v3.md`](v3.md) (3.0 shard content + the visibility framework), [`v4.md`](v4.md) (4.0 guild membership), [`v5.md`](v5.md) (5.0 decay schedule, vendor fees, login result), [`INTEGRATION.md`](INTEGRATION.md) (website API).
**Driven by** [`../website/EVENTS.md`](../website/EVENTS.md) and [`../website/EVENTS_PLAN.md`](../website/EVENTS_PLAN.md) Phase 11.
@@ -175,6 +175,25 @@ means here specifically: **the sidecar makes no idempotency promise of its own.*
does not cache, and does not know what a key means. The guarantee is the shard's, end to end, which
is the only place it can be — the shard is where the world write happens.
11b adds six routes and no new machinery. `event_call` is `admin_call` without the required
`actor`: an event verb's author is a **run**, which the body carries as `runId`, and demanding a
human name for something no human is doing would have the runner inventing one.
| Route | Command | Note |
|---|---|---|
| `GET /lease` | `lease.list` | The whole catalog with current values. One read serves both `read()` and `inForce()` on the website's side |
| `POST /lease` | `lease.apply` | |
| `POST /lease/release` | `lease.release` | A drifted answer is a **200** — see §8.3 |
| `POST /participation` | `participation.open` | |
| `POST /participation/:runId/snapshot` | `participation.snapshot` | **A POST for a read**, because it carries the caller's `idempotencyKey` and can be refused as a repeat in flight. A read that can legitimately answer 425 is not a GET |
| `POST /participation/:runId/close` | `participation.close` | |
`respond_event` is the fourth responder, and it exists for two mappings the generic one gets wrong:
a drifted lease is a 200 rather than a reason-sniffed 400, and the event plane being **switched off**
is a 403 rather than a 400 — `Bridge.EventsEnabled` is an operator's deliberate refusal, and telling
the website it sent a bad request would send an administrator hunting a bug in a step that is
written correctly.
### 3.1 Why 425 and not 409
409 is already the protocol-version gate's answer, and the two want **opposite dispositions** from a
@@ -206,6 +225,17 @@ ranked roll of who was strong enough to fell it. The kill is an event in the wor
is a performance record of named players that nobody consented to publish. A shard that wants a
public "who slew the champion" board lowers **one** field rule.
**11b's two frames are deliberately unmapped.** `lease.applied` and `lease.expired` are operational
records of the WEBSITE changing this shard's configuration — which key, from what to what, on whose
run, and whether the shard's own deadline had to put it back because nobody asked. Rule 2 fails an
unmapped kind closed to admin-only, which is where an audit trail of the site's own writes belongs;
mapping them would mean choosing a feature an operator could then widen, and there is no rung below
admin these belong on. Same reasoning as `account.login.result` in v5.
The participation ledger emits no stream frame at all. A tally is read on request, not broadcast:
a live feed of who is standing where would be a location tracker, and the ledger's whole justification
is that it answers one bounded question about one run.
**The trigger carries the count, never the names.** `uo.champ.boss_killed` exposes `damagerCount`
and a `damagerNote` sentence and no damager identity at all. A trigger variable is interpolated into
mail an operator may address to every subscriber, so a name reaching the trigger's data would undo
@@ -221,7 +251,8 @@ touching the visibility config at all.
| `servuo-plugins` | `BridgeIdempotency.cs` (new) · `BridgeBoot.OnInboundLine` gate · `BridgeLink.Emit` capture hook · `BridgeJson.RewriteStringField` / `WithTrueFlag` / `Damagers` · `BridgeChamps` boss-kill emitter · **`overlay.toml` `protocol = 6`, in the same PR as the emitters** |
| `link` | `PROTOCOL_VERSION` → 6 · `bridge.busy` → 425 in all three responders |
| `module-uo` | `uoLinkClient` ×3 writes carry the key · `uoEventActions` passes it and `uo.broadcast` becomes retryable · `shardVisibility` (kind + field rule) · `shardEngagement` mapper · `shardTriggers` + `engagementSeeds` for `uo.champ.boss_killed` |
| `docs` | this file · `INTEGRATION.md` · `PLAN.md` §5/§7 · `EVENTS.md` §A/§G · `EVENTS_PLAN.md` |
| `website` | **11b only.** `core.lease` gains a `reconcile()` and `registerEventLeases` gains an optional `inForce()` — see §8.4 |
| `docs` | this file · `INTEGRATION.md` · `PLAN.md` §5/§7 · `EVENTS.md` §A/§G · `EVENTS_PLAN.md` · `MODULE_API.md` (11b) |
| `installer` | **nothing.** See below |
| `runicgateway.com` | `platform.json.protocol` → 6 — deferred to the events cutover, because `checkFacts.mjs` fetches from `main` and setting it during the `edge` period turns that repo red immediately |
@@ -233,6 +264,11 @@ refuses a mismatch. The check is version-agnostic, so it needs no change for 6 e
none for 5. And `link` and `servuo-plugins` are on `edge` for this workstream, so nothing is
released or bundled until the events cutover in any case.
**`EVENTS_PLAN.md` was wrong about the repo count in the other direction too.** Phase 11 is four
repos for 11a and **five** for 11b: a lease's ledger row had no reconcile path anywhere, because the
step that made it names `core.lease`, and that is core's own action rather than a module's. There is
nowhere on that path a module could hang an answer, so core had to grow one. §8.4.
**The pin still has three declaration sites**`overlay.toml`, `PROTOCOL_VERSION`, and
`module-uo`'s `uo_link_config` default — and `module-uo`'s schema test asserts that they *agree*
rather than that they equal a literal. See v5 §5 for why that phrasing is load-bearing.
@@ -308,24 +344,285 @@ a consumer reading `region: ""` cannot tell "nowhere in particular" from "the sh
---
## 7. What 11b adds to protocol 6
## 7. One version, two halves
Phase 11 is split. **This document covers 11a**; 11b adds lease deadlines and the run-scoped
participation ledger to the *same* protocol version, amended in place rather than bumped to 7 —
6 will not have landed on `main` until the events cutover, and the org lead's 2026-09-03 rule is that
a protocol owes a bump once it has shipped and is amended in place before that.
Phase 11 is split. 11a bumped `PROTOCOL_VERSION` to 6; **11b amends 6 in place** rather than bumping
to 7 — 6 will not have landed on `main` until the events cutover, and the org lead's 2026-09-03 rule
is that a protocol owes a bump once it has shipped and is amended in place before that.
Which means: **an overlay and a sidecar both declaring `6` are only interchangeable within one side
of the 11b merge.** That is tolerable exactly because nothing is released from `edge` — the bundle
CI never sees either half until the cutover, by which time 6 means one thing. It would not be
tolerable on `main`, and this paragraph exists so nobody discovers that the hard way.
What 11b will add here:
Sections 8 and 9 are 11b. Everything above is 11a except where a section says otherwise.
- `lease.apply` / `lease.release` / `lease.list`, with a deadline the shard honours **without being
asked again** and a compare-and-set restore that reports `drifted` rather than overwriting a GM's
deliberate change.
- `participation.open` / `participation.snapshot` / `participation.close`, keyed by character serial
to match `module-uo`'s existing `memberKey`, and **persisted in the world save** — the Bridge's
first persisted state, so a tally survives a restart mid-event.
- The first handlers that **defer**, and therefore the first that can actually answer `bridge.busy`.
---
## 8. The lease plane (11b)
> An event does not edit the world. It holds a lease, and baseline is what is true when no lease is
> held.
>
> — `EVENTS.md`, *Leases: the primitive underneath everything*
Three commands, one new configuration gate, and two properties that are the whole reason the
framing is worth having.
### 8.1 `Bridge.EventsEnabled`, and why it is not `AdminWriteEnabled`
**Its own switch, default off** (org lead, 2026-09-04). Enabling the admin plane is an operator
consenting to staff moderation driven from the website — a human pressing kick or ban on a screen
they are looking at. A lease and a participation ledger are the website changing and watching the
world on a **schedule**, unattended, at four in the morning. Those are different consents and one
switch cannot honestly express both; an operator who wanted the first and got the second would be
right to be angry.
### 8.2 The commands
```json
{"kind":"lease.apply","reqId":"r-7","key":"PlayerCaps.SkillCap","value":"1200",
"holdMs":600000,"untilMs":1788567000000,"runId":"77","idempotencyKey":"…"}
```
| Command | Answers | |
|---|---|---|
| `lease.list` | `lease.list.ok` | Every allowlisted key: `current`, `default`, `min`/`max`, and where held, `baseline` / `applied` / `untilMs` / `runId` / `expired` |
| `lease.apply` | `lease.ok` | `baseline`, `applied`, `untilMs` |
| `lease.release` | `lease.ok` or `lease.drifted` | Compare-and-set |
Three shapes are worth stating because the obvious alternative is subtly wrong in each.
**`holdMs` is authoritative and `untilMs` is for display.** An absolute deadline computed on the
website and honoured on the shard is a deadline measured against **two clocks**, and a shard running
ten minutes fast would restore a ten-minute lease the instant it took it. A duration is immune. The
absolute time still crosses, because a console that can say when the hold ends in terms the
operator's own clock agrees with is worth one field.
**Values cross as TEXT, whatever the lease's declared type**, and comparison is done on the parsed
values. JSON would otherwise decide for us: `1200` and `1200.0` are one number to a parser and two
different strings to a compare-and-set, and a drift check that compared formatted numbers would
report drift on a value nobody had touched — refusing to restore, leaving the world changed, and
blaming an innocent operator.
**A lease held longer than the shard's ceiling is REFUSED, never clamped.** A clamp would quietly
give the website a shorter lease than it believes it has, and the website is the half that schedules
the restore; the two would then disagree about when the world comes back. `Bridge.LeaseMaxDurationSec`
is the shard's independent bound rather than a mirror of core's — it exists for the case where the
website is wrong, and being loud about it is the entire value.
### 8.3 The two mechanisms, and one thing a stock shard cannot do
**The deadline lives on the shard.** A lease arms a timer, and when it passes the shard restores
baseline **whether or not the website is ever heard from again**. Core drives the normal restore;
this is the backstop. It inverts the naive design, where restoration depends on core dispatching a
cleanup step and therefore fails *open* if core dies mid-event. A lease fails *safe*, and the worst
case is a world back at baseline early rather than one stuck changed indefinitely. The shard emits
`lease.expired` so the website learns what happened without being asked.
**Restore is compare-and-set, never a blind write.** If the current value is not what the event
applied, somebody moved it deliberately: answer `lease.drifted` with the current value, leave the
world alone, and let an operator decide. A **200**, not a 409 — the shard did exactly what it was
asked, and 409 is the version gate's with the opposite disposition. Blindly restoring would silently
revert a staff member's change, which is the one failure that would make operators distrust the
whole feature.
> **`Config.Set` has exactly ONE caller in the whole of ServUO 57.4** — `Server/ScriptCompiler.cs`,
> for `Compiler.Dynamic`. There is no in-game command, no gump and no console verb that writes a
> config key.
So on a stock shard a GM **cannot drift a configuration lease even deliberately**. The mechanism is
still correct and still required — Phase 12's object-property leases are trivially driftable, and a
shard with custom scripts may well write config at runtime — but proving it needs the `configset`
verb in `tools/scaffolding/BridgeRigDriver.cs`, which exists for exactly that reason.
**A lease is memory-only, and that is a decision.** `Config.Set` mutates the in-memory entry table;
`Config.Load()` is guarded by `_Initialized` and so runs once at boot, which is what makes a Set
survive every later Get. **Nothing ever calls `Config.Save()`**, so a shard restart is a *free*
restore — the strongest fail-safe available, at no cost. It is also why `lease.list` reports an empty
hand after a restart, which is precisely what lets the website's reconcile notice the lease is gone.
A pleasant consequence of `Config.Entry.Set`: restoring the baseline restores the entry's original
default marker too, because the entry compares against the value it was loaded with. Restoring a key
that was `@`-defaulted in a cfg file leaves it `@`-defaulted.
### 8.4 The reconcile hole, and `inForce()`
**A lease's ledger row had no reconcile path at all, and nothing failed to say so.** `cleanup.js`
resolves a resource to the action of the step that made it, and for a lease that action is
`core.lease` — a **core** action, on a path a module cannot register anything on. So every `override`
row came back `unanswered` for the life of the run, and a lease the shard had quietly dropped stayed
in the ledger as live until teardown went looking for a baseline nobody was holding.
11b closes it in two pieces, both in `website`:
- `core.lease` gains a `reconcile()`.
- `registerEventLeases` gains an **optional `inForce()`** — *"does the game side still have any
record of this hold?"*
It is deliberately not `read()` plus a comparison. A value that differs from what the run applied is
**drift**, which teardown must deliver through `restore()` so the row lands `drifted` with the
current value beside it; a reconcile that inferred absence from a changed value would orphan the row
first and destroy that signal — telling the operator the lease vanished rather than that somebody
moved it. Only an explicit `{ ok: true, held: false }` takes a row out; a throw, a timeout, an
unrecognised shape and a lease with no `inForce()` all leave it alone.
`MODULE_API_VERSION` stays **1.10.0**, amended in place, by the same rule §7 states for the protocol.
### 8.5 The catalog is short, and shorter than `EVENTS.md` expected
§D describes the 258 `Config.Get` call sites as splitting into two patterns — cached at type
initialisation, where a lease applies cleanly and does **nothing**, and read live, where it takes
effect at once. Measured on 57.4 the split is not near even: of the **158** non-Bridge call sites in
`Scripts/`, roughly **eight** are live reads.
11b ships **one** key: `PlayerCaps.SkillCap`, read live inside `CharacterCreation.cs`'s per-character
path and divided by ten to give the per-skill cap. It is both live and observable, which is what
"proven" has to mean here — the failure the allowlist exists to prevent is a key that applies
cleanly and changes nothing at all. Phase 12 adds the rest, with the boot-time self-check that drops
a key from the advertised catalog if it does not take.
---
## 9. The participation ledger (11b)
§G rates participation attribution as the largest remaining piece of new UO work, and says why
nothing composed out of the existing streams stands in for it: `region.enter` plus `mob.killed` is
loosely composable and **not trustworthy enough to publish results on**. Nothing scopes a kill or an
arrival to a run, nothing separates a passer-by from an attendee, and nothing survives a relog.
| Command | Answers | |
|---|---|---|
| `participation.open` | `participation.ok` | `{ runId, map, x, y, radius, holdMs }` |
| `participation.snapshot` | `participation.snapshot.ok` | The tally, resolved to names and accounts |
| `participation.close` | `participation.ok` | Stops counting; the tally stays readable through the grace window |
**The area is a map, a point and a radius** (org lead, 2026-09-04). Not a region name: §6.1 above
established that the most specific region containing an event is routinely **anonymous**, so a
region-named area would be undeclarable for exactly the venues events use. Not a rectangle either —
an author picks the spot the event happens at, not two opposite corners of it.
**Members are keyed by character serial**, matching `module-uo`'s existing Teams `memberKey`, so one
module speaks one member vocabulary and a participant joins to a roster without a translation table.
A player who attends on two characters is two members, which is the answer Teams already gives.
**The shard computes the score and core stores an opaque number it never interprets.** *"A minute
present plus five a kill"* is a sentence about Ultima Online, and the sentence has to live on the
Ultima Online side of the seam. The components ride along in the frame anyway, because a results
table that can say "forty minutes and three kills" beside a number is one an operator can defend
when a player argues with it.
Two shapes that look like details and are not:
- **Presence accrues in SECONDS, not sample counts.** A count would have to be multiplied by the
sweep interval to mean anything, and the interval is a config key an operator may change halfway
through a five-hour run — silently rewriting the first half of the tally. The kill weight is frozen
per run at open for the same reason.
- **Kill credit goes to every damager standing in the area, not to the killer.** A last hit is a poor
description of who fought something: the player who held it for four minutes and died to it took
part more than the one who landed the blow that finished it. The area test is applied to the
**damager**, so someone shooting in from outside is not attending and someone who has since walked
away accrues nothing more. Entries are summed per damager for the reason `champ.boss.killed`'s
table is (§2.2): an expired-and-recreated entry leaves two.
### 9.1 The Bridge's first persisted state
Nothing in this bridge has ever persisted anything. A ledger has to: a run spans hours and a restart
mid-event is an ordinary Tuesday, and an in-memory tally would silently regress every attendee's
score to whatever they earned after the restart. The only ways to paper over that from the other side
are a high-water rule in core — which must stay game-agnostic and cannot have one — or a per-run
offset in the module, which is the same bug with more moving parts.
`Server.Persistence` plus `EventSink.WorldSave` writes `Saves/Bridge/Participation.bin` beside the
world save, rather than a persistence **item**: no world object, no serial, nothing for a GM to find
and delete by accident, and a wipe of custom items leaves the ledger intact. The save and load hooks
are attached **unconditionally**, before the enabled gate is consulted — an operator who switches the
plane off for an afternoon must not come back to a truncated file where a run's tally used to be.
Bounds, all `Bridge.*` keys: eight runs counted at once, 2000 members per run, a 300-tile ceiling on
the area, and a 24-hour grace window after a run closes. A member the cap turns away is **counted**
and the count rides on every snapshot: a truncated tally that says it is truncated is usable, and one
that does not is a leaderboard with people missing from it for no stated reason.
### 9.2 The first handler that defers
`participation.snapshot` resolves every member serial to a mobile and an account, so a well-attended
run is hundreds of world lookups in one inbound call — exactly the work the Core thread must not be
handed in one piece. Above `Bridge.ParticipationSnapshotChunk` members it walks in chunks across
ticks, using `BridgeIdempotency.Hold` / `Complete`.
That makes it the first handler in the bridge to complete **after** its inbound call returns, and
therefore the first that can genuinely answer `bridge.busy`. 11a built that door and had nothing to
walk through it.
---
## 10. Verification (11b)
Unit tests: **588** in `module-uo/server` (17 new), **42** in `module-uo/client`, **2003** in
`website/server` (5 new), **47** in the sidecar (4 new). `cargo fmt`, `cargo clippy -D warnings` and
`check:imports` clean; the C# compiles against the real ServUO 57.4 reference assemblies with the
shard stopped.
The rig: a real ServUO with a seeded world, the **release** Rust sidecar, and
`tools/scaffolding/BridgeRigDriver.cs` (`configset` / `configread` / `partprobe`) plus
`BridgeParticipationProbe.cs`.
| Claim | Evidence |
|---|---|
| a lease applies, and the change is visible through the shard's own reader | `lease.apply``{"baseline":"1000","applied":"1200"}`; an independent `Config.Get` from a different class, long after every type initialiser, read `1200` |
| **the shard restores baseline with nobody asking** | A 20-second lease, and then silence. `[Bridge] lease PlayerCaps.SkillCap: deadline passed, restored to 1000 without being asked`, and `lease.expired` on the feed with `restored: true` |
| an expired lease still yields a verdict to teardown | `lease.list` reported `held: true, expired: true, restored: true`; the later `lease.release` answered `alreadyRestored: true` rather than an error |
| **a mid-lease GM edit produces `drifted`, and the world is LEFT ALONE** | `configset PlayerCaps.SkillCap 1350` under a live lease → `lease.release` answered `{"kind":"lease.drifted","current":"1350"}` at **200**, and a read afterwards still showed `1350` |
| a restart reverts a config lease, and the catalog says so | After a restart: `held: false`, `current: "1000"` — which is what makes `inForce()` correct |
| kill credit is per damager, inside the area | Two seeded players damaging one creature at the venue: both credited `kills: 1`, `score: 5.0` |
| **the tally survives a shard restart mid-run** | `save`, `shutdown`, boot: `[Bridge] participation: 1 run(s) restored from the world save`, and the snapshot returned both members with identical `firstMs` |
| **the first live `bridge.busy`** | Two concurrent `POST /participation/:runId/snapshot` under one key, chunk size 1: the first answered 200 with the tally, the second **425** `{"kind":"bridge.busy","busyKind":"participation.snapshot"}` |
| a deferred key replays like any other | A third request under the same key answered `replayed: true` under its own `reqId` and the **first attempt's** `t` |
### 10.1 The defect the deferral found, in 11a's own code
`bridge.busy` came back **200**, not 425, the first time anything produced it.
`BridgeIdempotency.Busy` built its frame with `BridgeJson.Begin("bridge.busy")` — which writes
`"kind":"bridge.busy"` — and then appended a diagnostic `.Str("kind", prior.Kind)` naming the command
that was in flight. **The object carried two `kind` fields, and every JSON parser worth the name
takes the last.** The sidecar matched on `bridge.busy` to decide the 425, read
`participation.snapshot` instead, and answered an ordinary 200 with a body saying nothing had
happened — the single worst of the three possible answers, since a retry loop would treat it as
success.
It shipped in 11a and **could not be seen there**: with only synchronous handlers a repeat can never
arrive mid-flight, so the arm was unreachable on a live shard, and the sidecar test that covers the
mapping was — correctly — feeding it a frame built by hand. The first deferring handler produced it
on its first collision. Renamed to `busyKind`.
This is the argument for the phase's ordering, stated as a fact rather than a hope: 11a said
*"11b's leases are the first thing that can actually produce it, and proving it belongs in that
walk"*, and the walk found a real bug in shipped code.
### 10.2 What the rig could not drive: presence
The participation ledger counts two things and only one of them is reachable headlessly.
**Presence needs a connected client.** The sweep credits online players — `NetState != null` — which
is the correct test and not one a probe should loosen: a character parked in Britain and logged out
for eight hours did not attend anything, and a ledger that said otherwise would put people at the top
of a leaderboard for being AFK. There is no way to produce a NetState short of writing a client, and
ClassicUO cannot be driven from this machine.
**Kill credit needs none**, so the whole of the credit path — the damager filter, the per-damager
fold, the area test on the damager, the member cap — ran exactly as it would in a fight, and the
accrual, persistence, snapshot, chunking and replay paths were driven by it. The one line the walk
did not exercise is `member.Seconds += seconds`, and it is named here rather than left to be assumed.
### 10.3 Two rig traps
- **`Core.Kill` does not save the world.** The rig driver's `shutdown` verb is a clean shutdown, which
is the only kind that *emits* — and it emits `server.shutdown` without writing a save. The first
restart test therefore reloaded an **empty** `Participation.bin` and looked exactly like a
persistence bug. `save` then `shutdown` is the sequence; the file's length is the check.
- **A probe that means to produce two damagers must not kill with the first blow.** An opening 40
damage on a Mongbat (around thirty hit points) killed it where it stood, so the second damager never
landed a hit, `DamageEntries` held one name, and the ledger correctly credited one player. It read
as a plugin crediting only the killer. Scaled to the creature's `HitsMax`.