@@ -26,13 +26,31 @@
  * dialect: a single-brace `{…}` token is refused, and the refusal names the
  * `{{ }}` spelling of each token or, for a token no hole can spell, where to
  * compute it. The contracts compose it (`NotifyConfigSchema`,
- * `ScreenConfigSchema`, `EndConfigSchema`), and `AutomationEngine.registerFlow`
- * and `objectstack validate` call it on every slot
+ * `HttpConfigSchema`, `ScreenConfigSchema`, `EndConfigSchema`), and
+ * `AutomationEngine.registerFlow` and the `validateStackExpressions` rule
+ * (`objectstack validate`, `objectstack compile`, the runtime publish gate of
+ * an `active` metadata save) call it on every slot
  * {@link flowNodeTextSlotSources} finds — ⛔ never a second reading of the
- * dialect anywhere. Those two doors then compile each slot's `{{ }}` holes
+ * dialect anywhere. Those doors then compile each slot's `{{ }}` holes
  * (`validateExpression('template', …)`), which the spec cannot do itself: the
  * template engine is a runtime.
  *
+ * ## Not at `FlowSchema.parse`, but for an `end` node (#23320)
+ *
+ * The flow parse runs this judge on one slot: a top-level `end` node's
+ * `message`, because `end` has no executor, so its contract, `EndConfigSchema`,
+ * has no door but the parse (`parseEndNodeConfig` in `flow.zod.ts`). On every
+ * other text slot the parse leaves the token to the doors above, as it leaves
+ * a value-slot token to the value-slot judge's: `flowNodeConfigRefusals`'
+ * value arm stands aside at the paths this judge refuses
+ * (`slotJudgeRefusedPaths`, #23260), and the parse calls no slot judge of its
+ * own. The reasons are measured once, for both judges, in
+ * `flow-value-slot-template.ts` ("The doors that run it"): a refusal at the
+ * parse would replace `registerFlow`'s located line and `objectstack
+ * validate`'s `expression-invalid` finding with the parse's issue list, and
+ * would fail the row in the stored pass (`os migrate meta --stored`), whose
+ * verdict a refusal after the parse leaves unmoved.
+ *
  * ## Refused, not converted (ADR-0087 D2)
  *
  * D2 lets a conversion rewrite only what maps LOSSLESSLY. Every token spelling
 
@@ -28,6 +28,48 @@
  * `AutomationEngine.registerFlow`, `objectstack validate` and the executors
  * call it — ⛔ never a second reading of the dialect anywhere.
  *
+ * ## The doors that run it — and why `FlowSchema.parse` is not one (#23320)
+ *
+ * The judge runs at every door that reports a flow's refusals per slot:
+ * `AutomationEngine.registerFlow`, after its parse; the `validateStackExpressions`
+ * rule (`expression-invalid` at `error`), which `objectstack validate`,
+ * `objectstack compile` and the runtime publish gate of an `active` metadata
+ * save run; and every run, through the node contracts that compose
+ * `FlowValueSlotSchema`. The flow parse does NOT run it: `FlowSchema.parse`,
+ * and so `defineStack`, `ObjectStackDefinitionSchema`, the `flow` metadata
+ * type's schema and an artifact's parse, accept a value-slot token. The parse
+ * parses the node contracts too (`flowNodeConfigRefusals`' value arm), and
+ * that arm stands aside at exactly the paths this judge refuses
+ * (`slotJudgeRefusedPaths`, #23260), so the parse leaves the token to the
+ * doors above, on purpose. Two measured reasons, taken by running this judge
+ * and the text-slot judge in `FlowSchema`'s refinement and reverting it:
+ *
+ *  - **The located refusal.** `registerFlow` parses first, and a parse
+ *    refusal reaches its caller as the parse's own issue list. A token
+ *    refused at the parse would replace `registerFlow`'s located line — the
+ *    node's id and type, the slot's label, the config path, the remedy and the
+ *    `source:` — at registration and in the boot's log, and `objectstack
+ *    validate` and `objectstack compile`, which parse the stack before their
+ *    rules run, would stop at the parse before the `expression-invalid`
+ *    finding. Every pin of either located refusal went red.
+ *  - **The stored pass.** The parse is also the stored-flow canonicalization
+ *    (`AutomationEngine.canonicalizeStoredFlow`) that `os migrate meta
+ *    --stored` runs on each flow row, and a parse refusal reports the row
+ *    `failed`, which flips `storedMigrationClean`: a non-zero exit that no run
+ *    of the command can clear, because no conversion rewrites the token (the
+ *    next section). A refusal after the parse is listed instead, as a TODO
+ *    under the step-18 D3 entry `flow-value-slot-template-dialect-refused`
+ *    (`conversions/refused-shapes.ts`), and the verdict does not move. The
+ *    pin that a braced filter operand parses and is listed went red.
+ *
+ * What this leaves: a stack built by `defineStack` and handed to none of those
+ * doors — `os dev` and `os serve` load it and boot — reaches `registerFlow` at
+ * boot, which refuses the flow with its located line and does not register it.
+ * The judge can join the parse once `registerFlow` reports a parse refusal as
+ * located as its own and the stored pass lists a slot the parse refuses
+ * rather than failing its row; the contract arm's exemption then keeps each
+ * token reported once.
+ *
  * ## Refused, not converted (ADR-0087 D2)
  *
  * D2 lets a conversion rewrite only what maps LOSSLESSLY. Every token spelling
 
@@ -1503,7 +1503,10 @@ export const FlowSchema = lazySchema(() => strictObject(
   //    value carrying a `{token}` included since #23260 (`get_record`
   //    `limit: '{x}'`), never a region slot, a ledger predicate or value slot,
   //    a value or text slot whose own judge refuses its token, or `http`'s
-  //    run-resolved `signingSecret`. A KEY its
+  //    run-resolved `signingSecret`. (#23320) This parse runs neither slot
+  //    judge itself, but for an `end` node's `message` through its contract:
+  //    the doors that do, and the measured reasons the parse is not one, are
+  //    in `flow-value-slot-template.ts` ("The doors that run it"). A KEY its
   //    contract does not declare is refused too (#21982), for every builtin
   //    `builtinNodeConfigKeysJudged` names (every one, `try_catch` included
   //    since #22343), a body-less legacy `loop` included. The one plugin node contract the spec declares, `approval`