@@ -0,0 +1,12 @@
+---
+'@objectstack/service-automation': patch
+'@objectstack/mcp': patch
+---
+
+fix(service-automation,mcp): a time-relative flow's conditions are typed against the object its sweep scans, at registration and in the `validate_expression` advice
+
+Clause-②: no
+Metadata-protocol: none
+
+- **`@objectstack/service-automation`**: the registration pass's advisory schema check (the logged `unknown field` / typo / type-mismatch warnings) typed a time-relative flow's conditions against the start node's `config.objectName`, while the run binds a row of `config.timeRelative.object`. A flow stored with a start naming another object kept a warning on a field that is right for the scanned object and none on a field that fails at run time; a start naming no `objectName` got no schema check at all. The pass now reads the object off the flow's trigger binding, the same answer the run uses: `timeRelative.object` when it is a string, `config.objectName` only otherwise. Every other flow is typed as before. The warnings stay logged, never thrown.
+- **`@objectstack/mcp`**: `validate_expression`'s description, its `sweepObject` input text and the SKILL.md line no longer advise passing a `sweepObject` other than `objectName` as a supported shape. They say to pass the scanned object as `objectName`, and that a start whose `objectName` names another object is refused at publish (`flow-time-relative-object-mismatch`). The tool's inputs and verdicts are unchanged.
@@ -1099,12 +1099,13 @@ export function registerObjectTools(
           'build-time errors (bare field refs, unknown fields, unknown functions) and advisory warnings ' +
           '(text/boolean fields misused in arithmetic, an error at a `validation` site, worded for the rule\'s ' +
           '`severity`, and at a `flow_condition` of a record-triggered or time-relative flow, where it fails the run; ' +
-          'a warning on any other flow, a time-relative sweep of another object included; date-equality pitfalls), plus the fields and stdlib ' +
+          'a warning on any other flow; date-equality pitfalls), plus the fields and stdlib ' +
           'functions in scope so you can self-correct. `site` says where the expression will live: a `formula` ' +
           'field, a `validation`/predicate, or a `flow_condition` (fields are bound bare in flow conditions). ' +
-          'Pass the rule\'s `severity` (validation) or the flow\'s `triggerKind` (flow_condition), and a time-relative ' +
-          'flow\'s `sweepObject` when it sweeps another object than objectName, so the verdict is the one the publish ' +
-          'gate gives that rule or flow.',
+          'Pass the rule\'s `severity` (validation) or the flow\'s `triggerKind` (flow_condition), so the verdict is ' +
+          'the one the publish gate gives that rule or flow. A time-relative flow\'s conditions read a row of the object ' +
+          'its sweep scans (`timeRelative.object`): pass that object as objectName. A start whose objectName names ' +
+          'another object is refused at publish (`flow-time-relative-object-mismatch`).',
         inputSchema: strictToolInput(
           {
             surface: 'this validate_expression call',
@@ -1145,10 +1146,11 @@ export function registerObjectTools(
               .string()
               .optional()
               .describe(
-                'site flow_condition with triggerKind time_relative only: the flow\'s `timeRelative.object`, whose rows ' +
-                'the sweep hands each run as its record. objectName is the object the conditions are typed against: the ' +
-                'start node\'s objectName, else the swept object itself. When sweepObject is another object, a type ' +
-                'mismatch is a warning, not an error: the run\'s record is a row of sweepObject. Default: objectName.',
+                'site flow_condition with triggerKind time_relative only: the flow\'s `timeRelative.object`, the object ' +
+                'the sweep scans and whose rows it hands each run as its record. Its conditions are typed against that ' +
+                'object, so it is objectName too. A start whose objectName names another object is refused at publish ' +
+                '(`flow-time-relative-object-mismatch`); passed with another objectName, the verdict is the gate\'s ' +
+                'advisory one for such a flow, a type mismatch warning. Default: objectName.',
               ),
           },
         ),
 
@@ -275,8 +275,10 @@ create/update payload.
   \`flow_condition\` | \`template\` (default \`formula\`). Pass the rule's
   \`severity\` or the flow's \`triggerKind\` (\`record_change\` by default) to
   get the verdict the publish gate gives that rule or flow; for a
-  \`time_relative\` flow that sweeps another object than \`objectName\`, also
-  pass its \`timeRelative.object\` as \`sweepObject\` (then a mismatch warns).
+  \`time_relative\` flow, pass the object its sweep scans (\`timeRelative.object\`)
+  as \`objectName\`: its conditions read rows of that object, and a start whose
+  \`objectName\` names another object is refused at publish
+  (\`flow-time-relative-object-mismatch\`). \`sweepObject\` names that same object.
 - **query_records({ objectName, where?, fields?, limit?, offset?, orderBy? })** —
   read records. \`where\` is a field→value match, e.g. \`{ "status": "open" }\`.
   Results are page-capped; use \`limit\`/\`offset\` to page.
 
@@ -9003,6 +9003,9 @@ export class AutomationEngine implements IAutomationService {
      * (unknown-field refs, likely bare-field typos, text/boolean fields misused
      * in arithmetic) as ADVISORY warnings (logged, never thrown). Flow conditions
      * bind the record's fields flat, so the schema pass uses `flattened` scope.
+     * The object they are typed against is the one the run binds: a
+     * time-relative flow's swept object, read off {@link deriveTriggerBinding}
+     * (#30396).
      * The fatal set is unchanged — a resolver can never break a flow that used to
      * register cleanly. `advisory: false` skips that pass: the stored pass
      * previews refusals ({@link registrationCheckRefusals}), and an advisory
@@ -9022,6 +9025,7 @@ export class AutomationEngine implements IAutomationService {
             logger: this.logger,
             objectSchemaResolver: this.objectSchemaResolver,
             valueEnvelopeRefusals: (...a) => this.valueEnvelopeRefusals(...a),
+            deriveTriggerBinding: (...a) => this.deriveTriggerBinding(...a),
         };
         return validateFlowExpressions.call(host, flowName, flow, { advisory });
     }
 
@@ -0,0 +1,84 @@
+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+import { describe, it, expect } from 'vitest';
+import { AutomationEngine } from './engine.js';
+
+/**
+ * The registration pass's advisory schema check (#1928) types a flow's
+ * conditions against ONE object. For a time-relative flow that object is the
+ * one the run binds — `config.timeRelative.object` when it is a string, the
+ * start node's `config.objectName` only otherwise (`deriveTriggerBinding`) —
+ * because the sweep launches each run with a row of THAT object as its record
+ * (#30396). A start whose `objectName` names another object is refused at
+ * publish (`flow-time-relative-object-mismatch`), but a flow stored before
+ * that rule still registers, so the advisory must point at the scanned object.
+ */
+function loggerCapturing(warns: string[]) {
+    const l: any = {
+        info: () => {}, error: () => {}, debug: () => {},
+        warn: (m: string) => warns.push(m),
+        child: () => l,
+    };
+    return l;
+}
+
+const SCHEMAS: Record<string, { fields: string[]; fieldTypes: Record<string, string> }> = {
+    // The start node's objectName in the two-object flow — NOT what the run binds.
+    crm_account: { fields: ['industry'], fieldTypes: { industry: 'text' } },
+    // The swept object: every run's record is one of its rows.
+    crm_contract: { fields: ['end_date', 'renewal_status'], fieldTypes: { end_date: 'date', renewal_status: 'select' } },
+};
+
+function timeRelativeFlow(condition: string, startObject: string | undefined) {
+    return {
+        name: 'renewal_alert', label: 'Renewal Alert', type: 'schedule',
+        nodes: [
+            {
+                id: 'start', type: 'start', label: 'Start',
+                config: {
+                    ...(startObject ? { objectName: startObject } : {}),
+                    timeRelative: { object: 'crm_contract', dateField: 'end_date', offsetDays: [30] },
+                    schedule: { type: 'cron', expression: '0 8 * * *' },
+                },
+            },
+            { id: 'check', type: 'decision', label: 'Check', config: { condition } },
+            { id: 'end', type: 'end', label: 'End' },
+        ],
+        edges: [
+            { id: 'e1', source: 'start', target: 'check' },
+            { id: 'e2', source: 'check', target: 'end' },
+        ],
+    };
+}
+
+function register(flow: unknown): string[] {
+    const warns: string[] = [];
+    const engine = new AutomationEngine(loggerCapturing(warns));
+    engine.setObjectSchemaResolver((name) => SCHEMAS[name]);
+    expect(() => engine.registerFlow('renewal_alert', flow as never)).not.toThrow();
+    return warns.filter((m) => /unknown field|did you mean|type mismatch/i.test(m));
+}
+
+describe('registration advisory: a time-relative flow is typed against the swept object (#30396)', () => {
+    it('a stored two-object flow: a field of the swept object passes', () => {
+        expect(register(timeRelativeFlow('record.renewal_status == "pending"', 'crm_account'))).toEqual([]);
+    });
+
+    it('a stored two-object flow: a field only the start node\'s objectName has warns', () => {
+        const warns = register(timeRelativeFlow('record.industry == "tech"', 'crm_account'));
+        expect(warns).toHaveLength(1);
+        expect(warns[0]).toMatch(/unknown field `industry`/);
+    });
+
+    it('a one-object flow (objectName equals timeRelative.object) is unchanged', () => {
+        expect(register(timeRelativeFlow('record.renewal_status == "pending"', 'crm_contract'))).toEqual([]);
+        expect(register(timeRelativeFlow('record.renewl_status == "pending"', 'crm_contract')).join('\n'))
+            .toMatch(/unknown field `renewl_status`/);
+    });
+
+    it('a sweep-only flow (no objectName) is typed against the swept object', () => {
+        expect(register(timeRelativeFlow('record.renewal_status == "pending"', undefined))).toEqual([]);
+        expect(register(timeRelativeFlow('record.industry == "tech"', undefined)).join('\n'))
+            .toMatch(/unknown field `industry`/);
+    });
+});
@@ -435,7 +435,7 @@ export function collectUndeclaredConfigKeys(
 
 /** The body of {@link AutomationEngine.validateFlowExpressions}, moved unedited; that method's docblock is its contract. */
 export function validateFlowExpressions(
-    this: Pick<RegistrationCheckHost, 'logger' | 'objectSchemaResolver' | 'valueEnvelopeRefusals'>,
+    this: Pick<RegistrationCheckHost, 'logger' | 'objectSchemaResolver' | 'valueEnvelopeRefusals' | 'deriveTriggerBinding'>,
     flowName: string,
     flow: FlowParsed,
     { advisory }: { advisory: boolean },
@@ -448,12 +448,23 @@ export function validateFlowExpressions(
         sites.push({ path, from: JSON.stringify(String(source)), detail: `${where}: ${message}` });
     };
 
-    // Resolve the flow's record-change target object (start node's
-    // `config.objectName`) so `record.*`/bare field refs can be checked
-    // against the real schema. Absent resolver / non-record flow → the hint
-    // is undefined and only the fatal syntax/bare-ref pass runs (unchanged).
+    // Resolve the object whose row each run binds as its record, so
+    // `record.*`/bare field refs can be checked against the real schema: the
+    // start node's `config.objectName`, except on a time-relative flow, whose
+    // run binds the object its sweep scans (#30396). That answer is read off
+    // the trigger binding itself (`deriveTriggerBinding`: `timeRelative.object`
+    // when it is a string, `config.objectName` only otherwise), not restated
+    // here — the readiness rule `flow-time-relative-object-mismatch` refuses a
+    // start naming another object at publish, but a flow stored before it
+    // still registers, and its advisory must speak of the scanned object.
+    // Absent resolver / no object → the hint is undefined and only the fatal
+    // syntax/bare-ref pass runs (unchanged); the stored pass (`advisory:
+    // false`) never reads the hint, so it derives no binding.
     const startNode = flow.nodes.find((n) => n.type === 'start');
-    const objectName = ((startNode?.config ?? {}) as Record<string, unknown>).objectName;
+    const bound = advisory && this.objectSchemaResolver ? this.deriveTriggerBinding(flowName, flow) : undefined;
+    const objectName = bound?.triggerType === 'time_relative'
+        ? bound.binding.object
+        : ((startNode?.config ?? {}) as Record<string, unknown>).objectName;
     const schemaHint = typeof objectName === 'string'
         ? (() => {
             const s = this.objectSchemaResolver?.(objectName);