From dd531b27ad98dc47f3c6d259cfa34e872d880b89 Mon Sep 17 00:00:00 2001
From: Bernhard Seefeld <berni@common.tools>
Date: Mon, 17 Nov 2025 16:11:29 -0800
Subject: [PATCH] fix(llm-dialog): when re-creating schema via source cell,
 follow cell path

---
 packages/runner/src/builtins/llm-dialog.ts | 25 +++++++++++++++-------
 packages/runner/src/cfc.ts                 |  2 +-
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/packages/runner/src/builtins/llm-dialog.ts b/packages/runner/src/builtins/llm-dialog.ts
index 1c9ac5dd13..4b80c9153d 100644
--- a/packages/runner/src/builtins/llm-dialog.ts
+++ b/packages/runner/src/builtins/llm-dialog.ts
@@ -93,14 +93,23 @@ function normalizeInputSchema(schemaLike: unknown): JSONSchema {
 function getCellSchema(
   cell: Cell<unknown>,
 ): JSONSchema | undefined {
-  return cell.schema ??
-    // If cell has a source cell, any resultRef has a schema attached
-    cell.getSourceCell<{ resultRef: Cell<unknown> }>({
-      type: "object",
-      properties: { resultRef: { asCell: true } },
-    })?.get()?.resultRef?.schema ??
-    // Otherwise, derive a simple object schema from the current value
-    buildMinimalSchemaFromValue(cell);
+  if (cell.schema) return cell.schema;
+
+  const sourceCell = cell.getSourceCell<{ resultRef: Cell<unknown> }>({
+    type: "object",
+    properties: { resultRef: { asCell: true } },
+  });
+  const sourceCellSchema = sourceCell?.key("resultRef").get()?.schema;
+  if (sourceCellSchema !== undefined) {
+    const cfc = new ContextualFlowControl();
+    return cfc.schemaAtPath(
+      sourceCellSchema,
+      cell.getAsNormalizedFullLink().path,
+      cell.schema,
+    );
+  }
+
+  return buildMinimalSchemaFromValue(cell);
 }
 
 function buildMinimalSchemaFromValue(charm: Cell<any>): JSONSchema | undefined {
diff --git a/packages/runner/src/cfc.ts b/packages/runner/src/cfc.ts
index da66d7c3e9..3c200986d1 100644
--- a/packages/runner/src/cfc.ts
+++ b/packages/runner/src/cfc.ts
@@ -505,7 +505,7 @@ export class ContextualFlowControl {
    */
   schemaAtPath(
     schema: JSONSchema,
-    path: string[],
+    path: readonly string[],
     rootSchema?: JSONSchema,
     extraClassifications?: Set<string>,
   ): JSONSchema {