fix(chat): narrate task-chat step numbers 1-based to match the card's step count

The proactive status narration printed the internal 0-based step index, so the
final step of a 13-step task announced "Starting Step 12" next to a card
showing "12/13". Display now uses index + 1 in both the engine builders and
the store-side updateStep narration; the 0-based tool/PROMPT.md contract is
unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.changeset/step-narration-one-based.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Task chat step narration now shows 1-based step numbers matching the task card's step count.
+category: fix
+dev: Display-only change in proactive-status.ts builders and merge-queue-ops proactiveStepStatusMessage; the 0-based step-index contract (tools, PROMPT.md headings, run-audit) is unchanged.

packages/core/src/__tests__/postgres/proactive-step-status.pg.test.ts

@@ -36,8 +36,9 @@ pgTest("proactive step-status chat entries (PostgreSQL)", () => {
 
     const statuses = (await harness.store.getAgentLogs(task.id, { type: "status" })).map((entry) => entry.text);
     expect(statuses).toEqual([
-      "Step 0 finished — Implement the change.",
-      "Step 0 was returned to pending — Implement the change.",
+      // Narration displays 1-based numbers (0-based index 0 → "Step 1") to match the task card.
+      "Step 1 finished — Implement the change.",
+      "Step 1 was returned to pending — Implement the change.",
     ]);
   });
 });

packages/core/src/task-store/merge-queue-ops.ts

@@ -41,16 +41,20 @@ function proactiveStepStatusMessage(
   status: import("../types.js").StepStatus,
 ): string | null {
   if (previousStatus === status) return null;
-  const label = stepName.trim() || `Step ${stepIndex}`;
+  // FNXC:ProactiveChatStatus 2026-07-23-10:30:
+  // Chat narration must display 1-based step numbers to match the task card's "N/M steps"
+  // counting; stepIndex stays 0-based in the store/tool contract (see proactive-status.ts).
+  const display = stepIndex + 1;
+  const label = stepName.trim() || `Step ${display}`;
   switch (status) {
     case "in-progress":
-      return `Starting Step ${stepIndex}: ${label}`;
+      return `Starting Step ${display}: ${label}`;
     case "done":
-      return `Step ${stepIndex} finished — ${label}.`;
+      return `Step ${display} finished — ${label}.`;
     case "skipped":
-      return `Step ${stepIndex} was skipped — ${label}.`;
+      return `Step ${display} was skipped — ${label}.`;
     case "pending":
-      return `Step ${stepIndex} was returned to pending — ${label}.`;
+      return `Step ${display} was returned to pending — ${label}.`;
   }
 }
 

packages/engine/src/__tests__/proactive-status.test.ts

@@ -33,10 +33,12 @@ describe("proactive status narration", () => {
   });
 
   it("builds complete status messages and safely reports unavailable reviews", () => {
-    expect(buildStepStartMessage(2, "Ship it")).toBe("Starting Step 2: Ship it");
-    expect(buildStepSuccessMessage(2, "Ship it")).toBe("Step 2 finished — Ship it.");
-    expect(buildStepSkippedMessage(2, "No code change needed")).toBe("Step 2 was skipped — No code change needed.");
-    expect(buildStepSkippedMessage(2, "Step 2")).toBe("Step 2 was skipped.");
+    // Narration displays 1-based step numbers (0-based index 2 → "Step 3") to match the task card.
+    expect(buildStepStartMessage(2, "Ship it")).toBe("Starting Step 3: Ship it");
+    expect(buildStepSuccessMessage(2, "Ship it")).toBe("Step 3 finished — Ship it.");
+    expect(buildStepSkippedMessage(2, "No code change needed")).toBe("Step 3 was skipped — No code change needed.");
+    // A caller-defaulted name of "Step <0-based index>" is treated as unnamed, not echoed.
+    expect(buildStepSkippedMessage(2, "Step 2")).toBe("Step 3 was skipped.");
     expect(buildStepFailureMessage(2, "Ship it", sanitizeFailureReason(undefined))).toContain("No failure reason");
     expect(buildPlanVerifiedMessage()).toBe("The plan was written and verified.");
     expect(buildReviewVerdictMessage("UNAVAILABLE", "nope")).toBeNull();

packages/engine/src/proactive-status.ts

@@ -39,18 +39,33 @@ export function sanitizeFailureReason(rawError: unknown): string {
   return sanitized;
 }
 
-function stepLabel(stepIndex: number, stepName?: string): string {
-  const fallback = `Step ${stepIndex}`;
-  return stepName?.trim() || fallback;
+/*
+FNXC:ProactiveChatStatus 2026-07-23-10:30:
+Step indices are 0-based everywhere in the agent-facing contract (fn_task_update, PROMPT.md
+"### Step 0:" headings, run-audit rows), but the task card counts steps 1-based ("12/13").
+Chat narration is read next to the card, so it must display stepIndex + 1 or the final step of a
+13-step task announces itself as "Step 12" while the card shows 13 steps. Only the display number
+converts; callers keep passing the 0-based index, and a fallback name of "Step <0-based index>"
+(produced by callers that default the name from the index) is treated as "unnamed".
+*/
+function stepDisplayNumber(stepIndex: number): number {
+  return stepIndex + 1;
+}
+
+function stepDisplayName(stepIndex: number, stepName?: string): string | undefined {
+  const name = stepName?.trim();
+  return name && name !== `Step ${stepIndex}` ? name : undefined;
 }
 
 export function buildStepStartMessage(stepIndex: number, stepName?: string): string {
-  return `Starting Step ${stepIndex}: ${stepLabel(stepIndex, stepName)}`;
+  const display = stepDisplayNumber(stepIndex);
+  return `Starting Step ${display}: ${stepDisplayName(stepIndex, stepName) ?? `Step ${display}`}`;
 }
 
 export function buildStepSuccessMessage(stepIndex: number, stepName?: string): string {
-  const name = stepName?.trim();
-  return name && name !== `Step ${stepIndex}` ? `Step ${stepIndex} finished — ${name}.` : `Step ${stepIndex} finished.`;
+  const name = stepDisplayName(stepIndex, stepName);
+  const display = stepDisplayNumber(stepIndex);
+  return name ? `Step ${display} finished — ${name}.` : `Step ${display} finished.`;
 }
 
 /**
@@ -59,12 +74,15 @@ export function buildStepSuccessMessage(stepIndex: number, stepName?: string): s
  * preflight and intentional no-op flows remain visible without fabricating a failure reason.
  */
 export function buildStepSkippedMessage(stepIndex: number, stepName?: string): string {
-  const name = stepName?.trim();
-  return name && name !== `Step ${stepIndex}` ? `Step ${stepIndex} was skipped — ${name}.` : `Step ${stepIndex} was skipped.`;
+  const name = stepDisplayName(stepIndex, stepName);
+  const display = stepDisplayNumber(stepIndex);
+  return name ? `Step ${display} was skipped — ${name}.` : `Step ${display} was skipped.`;
 }
 
 export function buildStepFailureMessage(stepIndex: number, stepName: string | undefined, safeReason: string): string {
-  const prefix = stepName?.trim() && stepName.trim() !== `Step ${stepIndex}` ? `Step ${stepIndex} (${stepName.trim()})` : `Step ${stepIndex}`;
+  const name = stepDisplayName(stepIndex, stepName);
+  const display = stepDisplayNumber(stepIndex);
+  const prefix = name ? `Step ${display} (${name})` : `Step ${display}`;
   return `${prefix} did not complete: ${safeReason}`;
 }