@@ -0,0 +1,53 @@
+---
+"@objectstack/spec": patch
+---
+
+fix(spec): unknown-key suggestions no longer point authors at keys the schema rejects (#5013)
+
+An `aliases` table on an authoring schema is a **claim about that schema**, in
+two halves: that the key it is filed under is one the shape *rejects* (an alias
+is consulted only from the `unrecognized_keys` path, so a key the shape declares
+can never reach it), and that the key it prescribes is one the shape *accepts*.
+Nothing checked either half, and both were false on `main`.
+
+Writing `filter` on a report produced:
+
+```
+Unrecognized key(s) on this report: `filter`. … Did you mean `filter` -> `filters`?
+```
+
+and taking that advice produced a **second** rejection — `ReportSchema` declares
+neither `filter` nor `filters`, only `runtimeFilter` — this time with no
+suggestion at all. That is the exact failure the unknown-key strictness work
+exists to remove, shipped by its own fix, and it is worst for AI authors whose
+only signal is whether the parse complained.
+
+**What changed** — no authorable key was added or removed, so nothing that
+parsed before stops parsing; only the guidance an author gets when a key is
+rejected:
+
+- `ReportSchema` — `filter`, `filters`, `where` and `criteria` now all name
+  `runtimeFilter`, matching `JoinedReportBlockSchema`'s table verbatim so a
+  report and its sub-reports correct the author identically.
+- `EmailTemplateDefinitionSchema` — `html`/`content` name `bodyHtml`, `text`
+  names `bodyText`, and `from`/`sender` name `fromOverride`. All five previously
+  named `body` / `fromAddress`, neither of which the schema declares.
+- `SkillSchema` — `trigger` no longer renames onto `triggers` (never a key).
+  It now carries a prescription instead, because the correct answer is a split:
+  routing intent belongs in `triggerConditions`, natural-language intent in
+  `description` / `instructions`. A rename would have landed a phrase in an
+  array-of-conditions slot and been rejected on the value instead of the key.
+- Six entries filed under keys their own schema already declares — and which
+  therefore could never run — are gone: `columns` and `chart` on `ReportSchema`,
+  `measures` and `filter` on `DatasetSchema`, `body` on `ActionSchema`.
+
+**What keeps it true** — `strictObject` now records each shape it builds, and
+`alias-integrity.test.ts` judges every one of the 235 authoring surfaces in the
+package against the runtime `.shape` it makes claims about. Reading the runtime
+shape rather than the source is what makes it work: shapes spread
+(`...MetadataProtectionFields`), ten alias tables are assembled rather than
+written as literals, and two different schemas share the surface string
+`'this field group'` — a source-literal reader is wrong or blind on all three.
+An alias pointing at a **tombstone** is caught too, which the suggester's own
+`knownKeys` filter cannot do, since the alias table is consulted before that
+fallback runs.
@@ -67,8 +67,27 @@ export const SkillSchema = lazySchema(() => strictObject({
   surface: 'this skill',
   history:
     'Until #4001 closed this shape these were dropped silently — the item still registered, minus whatever the key was meant to configure.',
-  aliases: { prompt: 'instructions', content: 'instructions', body: 'instructions', trigger: 'triggers', tool: 'tools' },
+  aliases: { prompt: 'instructions', content: 'instructions', body: 'instructions', tool: 'tools' },
   guidance: {
+    // #5013 — `trigger` used to be an ALIAS pointing at `triggers`, a key this
+    // schema has never declared: the author was told to write it, wrote it, and
+    // was rejected a second time with no suggestion left to give.
+    //
+    // It is not repointed at `triggerConditions`, because a rename is the wrong
+    // instrument here. The prescription the `triggerPhrases` tombstone below
+    // carries is a SPLIT — routing intent goes to `triggerConditions`, natural
+    // language to `description` / `instructions` — so an author who wrote
+    // `trigger: 'create a case'` and took a rename would land a phrase in an
+    // array-of-conditions slot and be rejected on the value instead of the key.
+    // That is ledger finding 7 exactly: this campaign's own fix signposting the
+    // way back into the failure mode it exists to kill.
+    trigger:
+      '`trigger` is not a skill key, and skills have never been activated by a phrase. '
+      + 'Activation is `triggerConditions` (an AND of context field/operator/value) intersected '
+      + "with the agent's `skills[]` allowlist, plus explicit /skill-name pinning. If you meant a "
+      + 'programmatic condition, write `triggerConditions: [{ field: …, operator: …, value: … }]`; '
+      + 'if you meant natural-language intent for the LLM to route on, that belongs in '
+      + '`description` / `instructions`, which are the strings actually put in front of the model.',
     permissions:
       '`permissions` is not a skill key — skill invocation was never permission-gated, '
       + 'so this was stripped in silence and the author believed they had a gate. Gate at '