Merge PR #4166: fix(agent): preserve approved plan path (@roboomp)

packages/coding-agent/CHANGELOG.md

@@ -50,6 +50,9 @@
 ### Fixed
 
 - Fixed the multi-select (checkbox) `ask` picker showing no visible cursor on themes where `accent` fg is close to the terminal foreground; the focused option now renders as a full-width `selectedBg` highlight band spanning label and wrapped description rows, matching the Ctrl+R history overlay ([#4157](https://github.com/can1357/oh-my-pi/issues/4157)).
+### Fixed
+
+- Fixed approved plan execution prompts embedding the full plan instead of requiring the executor to read the durable `local://<slug>-plan.md` file. ([#4164](https://github.com/can1357/oh-my-pi/issues/4164))
 
 ## [16.2.12] - 2026-07-01
 

packages/coding-agent/src/plan-mode/approved-plan-prompt.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, it } from "bun:test";
+import { prompt } from "@oh-my-pi/pi-utils";
+import planModeApprovedPrompt from "../prompts/system/plan-mode-approved.md" with { type: "text" };
+import planModeCompactInstructionsPrompt from "../prompts/system/plan-mode-compact-instructions.md" with {
+	type: "text",
+};
+import planModeReferencePrompt from "../prompts/system/plan-mode-reference.md" with { type: "text" };
+
+const PLAN_FILE_PATH = "local://durable-plan.md";
+const PLAN_SENTINEL = "SENTINEL_HEADROOM_COMPRESSED_PLAN_CONTENT";
+
+describe("approved plan execution prompts", () => {
+	it("loads the approved plan from the durable local file instead of embedding content", () => {
+		const approved = prompt.render(planModeApprovedPrompt, {
+			planContent: PLAN_SENTINEL,
+			planFilePath: PLAN_FILE_PATH,
+			contextPreserved: false,
+		});
+		const reference = prompt.render(planModeReferencePrompt, {
+			planContent: PLAN_SENTINEL,
+			planFilePath: PLAN_FILE_PATH,
+		});
+		const compact = prompt.render(planModeCompactInstructionsPrompt, {
+			planFilePath: PLAN_FILE_PATH,
+		});
+
+		for (const rendered of [approved, reference, compact]) {
+			expect(rendered).toContain(PLAN_FILE_PATH);
+			expect(rendered).not.toContain(PLAN_SENTINEL);
+		}
+		expect(approved).toContain("MUST read `local://durable-plan.md`");
+		expect(reference).toContain("MUST read `local://durable-plan.md`");
+	});
+});

packages/coding-agent/src/prompts/system/plan-mode-approved.md

@@ -1,25 +1,22 @@
 Plan approved.
 {{#if contextPreserved}}
-- Context preserved. Use conversation history when useful; this plan is the source of truth if it conflicts with earlier exploration.
+- Context preserved. Use conversation history when useful; the plan file is the source of truth if it conflicts with earlier exploration.
 {{/if}}
 
 <instruction>
-You MUST execute this plan step by step. You have full tool access.
+You MUST read `{{planFilePath}}` before executing.
+The file content is the authoritative plan; visible/compressed context is secondary.
+Read failure? Report the exact path and error instead of guessing.
+After reading, you MUST execute the plan step by step with full tool access.
 You MUST verify each step before proceeding to the next.
 {{#has tools "todo"}}
-Before execution, initialize todo tracking with `todo`.
+After reading the plan, initialize todo tracking with `todo`.
 After each completed step, immediately update `todo`.
 If `todo` fails, fix the payload and retry before continuing.
 {{/has}}
-The plan path is for subagent handoff only. You already have the plan; NEVER read it.
 </instruction>
 
-The full plan is injected below. You MUST execute it now:
-
-<plan path="{{planFilePath}}">
-{{planContent}}
-</plan>
-
 <critical>
+NEVER stop because inline plan content is compressed, expired, or unrecoverable. Read `{{planFilePath}}`.
 You MUST keep going until complete. This matters.
 </critical>

packages/coding-agent/src/prompts/system/plan-mode-compact-instructions.md

@@ -12,5 +12,6 @@ You MUST drop:
 - Restated context already present in the plan file.
 
 {{#if planFilePath}}
-The approved plan file is at `{{planFilePath}}`; it is the authoritative source of truth and need not be re-summarized in detail.
+The approved plan file is at `{{planFilePath}}`; it is the authoritative source of truth.
+You MUST preserve this durable path and the fact that the executor must read it directly after compaction.
 {{/if}}

packages/coding-agent/src/prompts/system/plan-mode-reference.md

@@ -1,11 +1,10 @@
 ## Existing Plan
 
-<plan path="{{planFilePath}}">
-{{planContent}}
-</plan>
+The approved plan file is at `{{planFilePath}}`.
 
 <instruction>
 If this plan is relevant to current work and not complete, you MUST continue executing it.
+If you do not have the current plan content in visible context, you MUST read `{{planFilePath}}`.
 If the plan is stale or unrelated, you MUST ignore it.
-The plan path is for subagent handoff only. You already have the plan; NEVER read it.
+NEVER stop because inline plan content is compressed, expired, or unrecoverable. Read the file.
 </instruction>

packages/coding-agent/src/session/agent-session.ts

@@ -6666,9 +6666,8 @@ export class AgentSession {
 
 		const planFilePath = this.#planReferencePath;
 		const resolvedPlanPath = resolveLocalUrlToPath(planFilePath, this.#localProtocolOptions());
-		let planContent: string;
 		try {
-			planContent = await Bun.file(resolvedPlanPath).text();
+			await fs.promises.access(resolvedPlanPath, fs.constants.R_OK);
 		} catch (error) {
 			if (isEnoent(error)) {
 				return null;
@@ -6678,7 +6677,6 @@ export class AgentSession {
 
 		const content = prompt.render(planModeReferencePrompt, {
 			planFilePath,
-			planContent,
 		});
 
 		this.#planReferenceSent = true;