diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 71e86facb..287b92158 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -16,6 +16,7 @@
 - Fixed Bash internal URLs remaining unresolved when used as unquoted arguments inside command substitutions ([#5535](https://github.com/can1357/oh-my-pi/issues/5535)).
 - Fixed the built-in `fd` printing `fd: Broken pipe (os error 32)` when a downstream pipeline reader exited early (e.g. `fd … | head`); it now exits silently with 141 (128+SIGPIPE), matching real fd.
 - Fixed prewalk repeatedly continuing after a bash-only task such as `commit` had already completed ([#5551](https://github.com/can1357/oh-my-pi/issues/5551)).
+- Fixed plan-mode re-entry dropping a new plan request when a prior plan artifact existed: the re-entry prompt led with the old plan and contradicted the plan-file guidance, so weak models only reconciled the incomplete previous plan. Re-entry now anchors on the new request and folds any old-plan corrections into it ([#5576](https://github.com/can1357/oh-my-pi/issues/5576)).
 
 ## [16.5.2] - 2026-07-14
 
diff --git a/packages/coding-agent/src/plan-mode/reentry-prompt.test.ts b/packages/coding-agent/src/plan-mode/reentry-prompt.test.ts
new file mode 100644
index 000000000..2566c799e
--- /dev/null
+++ b/packages/coding-agent/src/plan-mode/reentry-prompt.test.ts
@@ -0,0 +1,41 @@
+import { describe, expect, it } from "bun:test";
+import { prompt } from "@oh-my-pi/pi-utils";
+import planModeActivePrompt from "../prompts/system/plan-mode-active.md" with { type: "text" };
+
+const BASE = {
+	planFilePath: "local://old-feature-plan.md",
+	askToolName: "ask",
+	writeToolName: "write",
+	editToolName: "edit",
+	isHashlineEditMode: false,
+	iterative: false,
+} as const;
+
+function render(overrides: { reentry: boolean; planExists: boolean }): string {
+	return prompt.render(planModeActivePrompt, { ...BASE, ...overrides });
+}
+
+describe("plan-mode re-entry prompt", () => {
+	it("only emits the Re-entry section when re-entering", () => {
+		expect(render({ reentry: false, planExists: true })).not.toContain("## Re-entry");
+		expect(render({ reentry: true, planExists: true })).toContain("## Re-entry");
+	});
+
+	it("anchors the turn on the new request, not the old plan", () => {
+		const rendered = render({ reentry: true, planExists: true });
+		const reentry = rendered.slice(rendered.indexOf("## Re-entry"));
+		// The new request is the primary input; the old plan is reference only.
+		expect(reentry).toMatch(/NEW request[\s\S]*primary input/);
+		// Corrections to an incomplete old plan must be folded into the new plan,
+		// never substituted for it (the reported failure: dropping the new request).
+		expect(reentry).toMatch(/combine, never substitute/);
+	});
+
+	it("does not contradict the planExists guidance on a different task", () => {
+		const rendered = render({ reentry: true, planExists: true });
+		// planExists branch: different task -> leave old plan, write a fresh file.
+		expect(rendered).toContain("leave that plan in place and start a fresh");
+		// Re-entry must agree; the old "Different task -> overwrite it" directive is gone.
+		expect(rendered).not.toMatch(/[Dd]ifferent task → overwrite/);
+	});
+});
diff --git a/packages/coding-agent/src/prompts/system/plan-mode-active.md b/packages/coding-agent/src/prompts/system/plan-mode-active.md
index 5056ff0be..0d25a8f94 100644
--- a/packages/coding-agent/src/prompts/system/plan-mode-active.md
+++ b/packages/coding-agent/src/prompts/system/plan-mode-active.md
@@ -48,11 +48,14 @@ Every question MUST change the plan or settle a load-bearing choice. Batch them.
 {{#if reentry}}
 ## Re-entry
 
+You are re-entering plan mode with a NEW request. That new request is the primary input and MUST be planned; the existing plan is only reference. You NEVER narrow the turn to reconciling the old plan and drop the new request.
+
 <procedure>
-1. Read the existing plan.
-2. Compare the new request against it.
-3. Different task → overwrite it. Same task continuing → update it and delete outdated sections.
-4. Call `resolve` with `action: "apply"` and `extra: { title }` when complete.
+1. Read the new request and make it the plan you build this turn.
+2. Read the existing plan as reference only.
+3. Same task continuing → update that plan with `{{editToolName}}` and delete outdated sections. Different task → leave that plan in place and write a fresh `local://<slug>-plan.md` for the new request.
+4. If the old plan has unfinished or broken work the new request depends on, fold those corrections INTO the new plan — combine, never substitute the old fix for the new request.
+5. Call `resolve` with `action: "apply"` and `extra: { title }` when the new request is decision-complete.
 </procedure>
 {{/if}}