`EVENTS.md` §H told a module the revert contract accepts a `detail` on its
envelope. `classify()` reads `ok`, `retry`, `error`, `await`, `holdFor`,
`resources` and `participants` — and has never read a `detail`. So a module
that answered one was writing into nothing.
`module-uo` believed it, twice, since Phase 12b:
* `uo.item.grant` answers `{ granted, missed, why }`
* `uo.world.save` answers `{ started: true }`
The grant is the one that matters. A grant reaches the players a run's
participation ledger holds, and **which of them missed out is knowable only to
the module and reported nowhere else** — so an operator saw a step marked
`done` and never learned four of twelve got nothing.
Found writing the integration kit's chapter 5 (`Integration-kit#10`), whose
template made the same mistake on §H's authority.
## What this adds
`detail` becomes a real, optional member of the two SUCCESS envelopes, beside
`resources` and `participants` — on both, because `await: 'human'` is a success
and a cue's confirm finishes the step without a second dispatch, so that is the
only moment its module could ever have said anything.
**Core never interprets it.** `safeDetail()` bounds it and nothing else reads a
key out of it, here or in the runner or in the browser. That is the point: a
module knows things about its own verb core cannot compute, and it had no other
way to say them.
* objects only — the column is JSON and the console renders keys, so a bare
string has nothing to render under, and core inventing a key would be core
interpreting it after all;
* 4KB of serialised JSON, dropped rather than truncated, because half a JSON
object is not a JSON object;
* unserialisable (circular, a throwing `toJSON`) is dropped — reaching the
runner would make the log INSERT throw, inside the one write documented
never to;
* re-parsed rather than passed through, so core holds no live reference into
a module's object;
* **anything wrong with it is dropped and logged, never a failure.** A step
that did what it was asked must not be re-run because its module's
commentary was malformed: that is a world write repeated for a log line.
The runner writes it as a `step.detail` run-log row, its own kind rather than a
field on `resource.recorded` — the grant that forced this ledgers nothing
(`reversible: 'none'`) and reports no participants, so it would have had
nowhere to ride.
## The renderer, which is half the fix
`describeLogLine`'s default returns a kind WORD, so a `step.detail` row falling
through would have rendered as the literal string "step.detail" — the channel
existing and showing nothing, exactly the failure being fixed. It gets a case
that renders whatever keys the module put there, generically: a switch on known
keys would be the browser learning one module's vocabulary.
uo.item.grant — granted: 8, missed: 4, why: bank full, offline
uo.world.save — started: true
**`module-uo` needs no change**: the code it already shipped starts working.
MODULE_API stays 1.10.0, amended in place — it is still on `edge`. Zero-line
route manifest diff; no route added. 2057 server tests, 400 client tests.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016wDDVXWMDz82WqE1i969r4
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