diff --git a/src/resources/extensions/sf/auto-post-unit.ts b/src/resources/extensions/sf/auto-post-unit.ts
index 49a18009a..a15410256 100644
--- a/src/resources/extensions/sf/auto-post-unit.ts
+++ b/src/resources/extensions/sf/auto-post-unit.ts
@@ -577,7 +577,7 @@ export async function postUnitPreVerification(
 				// git history object is only created once the unit is confirmed complete.
 				try {
 					const git = createGitService(s.basePath);
-					const staged = git.stageOnly();
+					const staged = git.stageOnly([], taskContext?.keyFiles ?? []);
 					if (staged) {
 						s.stagedPendingCommit = true;
 						s.pendingCommitTaskContext = taskContext ?? null;
diff --git a/src/resources/extensions/sf/git-service.ts b/src/resources/extensions/sf/git-service.ts
index b7e1b7a3e..ccf52a4b6 100644
--- a/src/resources/extensions/sf/git-service.ts
+++ b/src/resources/extensions/sf/git-service.ts
@@ -16,7 +16,7 @@ import {
 	readFileSync,
 	writeFileSync,
 } from "node:fs";
-import { join } from "node:path";
+import { isAbsolute, join, normalize } from "node:path";
 import {
 	QUICK_BRANCH_RE,
 	SLICE_BRANCH_RE,
@@ -24,10 +24,12 @@ import {
 } from "./branch-patterns.js";
 import { getErrorMessage } from "./error-utils.js";
 import { SF_GIT_ERROR, SF_MERGE_CONFLICT, SFError } from "./errors.js";
+import { normalizePlannedFileReference } from "./files.js";
 import { GIT_NO_PROMPT_ENV } from "./git-constants.js";
 import {
 	_resetHasChangesCache,
 	nativeAddAllWithExclusions,
+	nativeAddPaths,
 	nativeBranchExists,
 	nativeCommit,
 	nativeCommitSubject,
@@ -247,6 +249,40 @@ export const RUNTIME_EXCLUSION_PATHS: readonly string[] = [
 	".sf/DISCUSSION-MANIFEST.json",
 ];
 
+function isPathExcluded(path: string, exclusions: readonly string[]): boolean {
+	const normalized = path.replace(/\\/g, "/").replace(/^\.\//, "");
+	return exclusions.some((rawExclusion) => {
+		const exclusion = rawExclusion.replace(/\\/g, "/").replace(/^\.\//, "");
+		if (!exclusion) return false;
+		if (exclusion.includes("*")) {
+			const prefix = exclusion.slice(0, exclusion.indexOf("*"));
+			return normalized.startsWith(prefix);
+		}
+		if (exclusion.endsWith("/")) return normalized.startsWith(exclusion);
+		return normalized === exclusion || normalized.startsWith(`${exclusion}/`);
+	});
+}
+
+function normalizeExplicitStagePath(path: string): string | null {
+	const normalized = normalize(
+		normalizePlannedFileReference(path).replace(/\\/g, "/"),
+	)
+		.replace(/\\/g, "/")
+		.replace(/^\.\//, "");
+	if (
+		!normalized ||
+		normalized === "." ||
+		normalized.includes("\0") ||
+		isAbsolute(normalized) ||
+		/^[A-Za-z]:\//.test(normalized) ||
+		normalized === ".." ||
+		normalized.startsWith("../")
+	) {
+		return null;
+	}
+	return normalized;
+}
+
 // ─── Integration Branch Metadata ───────────────────────────────────────────
 
 /**
@@ -541,7 +577,10 @@ export class GitServiceImpl {
 	 * Falls back to plain `git add -A` if the exclusion pathspec fails.
 	 * @param extraExclusions Additional pathspec exclusions beyond RUNTIME_EXCLUSION_PATHS.
 	 */
-	private smartStage(extraExclusions: readonly string[] = []): void {
+	private smartStage(
+		extraExclusions: readonly string[] = [],
+		explicitIncludePaths: readonly string[] = [],
+	): void {
 		// One-time cleanup: if runtime files are already tracked in the index
 		// (from older versions where the fallback bug staged them), untrack them
 		// in a dedicated commit. This must happen as a separate commit because
@@ -607,6 +646,25 @@ export class GitServiceImpl {
 		}
 
 		nativeAddAllWithExclusions(this.basePath, allExclusions);
+		this.stageExplicitIncludePaths(explicitIncludePaths, allExclusions);
+	}
+
+	private stageExplicitIncludePaths(
+		paths: readonly string[],
+		exclusions: readonly string[],
+	): void {
+		const seen = new Set<string>();
+		const safePaths = paths
+			.map(normalizeExplicitStagePath)
+			.filter((path): path is string => path !== null)
+			.filter((path) => !isPathExcluded(path, exclusions))
+			.filter((path) => {
+				if (seen.has(path)) return false;
+				seen.add(path);
+				return true;
+			});
+		if (safePaths.length === 0) return;
+		nativeAddPaths(this.basePath, safePaths);
 	}
 
 	/** Tracks whether runtime file cleanup has run this session. */
@@ -650,7 +708,7 @@ export class GitServiceImpl {
 		// Native path uses libgit2 (single syscall), fallback spawns git.
 		if (!nativeHasChanges(this.basePath)) return null;
 
-		this.smartStage(extraExclusions);
+		this.smartStage(extraExclusions, taskContext?.keyFiles ?? []);
 
 		// After smart staging, check if anything was actually staged
 		// (all changes might have been runtime files that got excluded)
@@ -850,10 +908,15 @@ export class GitServiceImpl {
 	 * postUnitPostVerification once verification has passed.
 	 *
 	 * @param extraExclusions Additional paths to exclude from staging.
+	 * @param explicitIncludePaths Task-declared files to stage even when the
+	 * symlinked .sf fallback must avoid broad untracked traversal.
 	 */
-	stageOnly(extraExclusions: readonly string[] = []): boolean {
+	stageOnly(
+		extraExclusions: readonly string[] = [],
+		explicitIncludePaths: readonly string[] = [],
+	): boolean {
 		if (!nativeHasChanges(this.basePath)) return false;
-		this.smartStage(extraExclusions);
+		this.smartStage(extraExclusions, explicitIncludePaths);
 		return nativeHasStagedChanges(this.basePath);
 	}
 
diff --git a/src/resources/extensions/sf/tests/integration/git-service.test.ts b/src/resources/extensions/sf/tests/integration/git-service.test.ts
index 326689aa2..cbcfea98b 100644
--- a/src/resources/extensions/sf/tests/integration/git-service.test.ts
+++ b/src/resources/extensions/sf/tests/integration/git-service.test.ts
@@ -1740,6 +1740,45 @@ describe("git-service", async () => {
 		rmSync(externalGsd, { recursive: true, force: true });
 	});
 
+	test("GitServiceImpl: symlinked .sf stages explicit untracked task files", () => {
+		const repo = initTempRepo();
+		const externalGsd = mkdtempSync(join(tmpdir(), "sf-external-"));
+		mkdirSync(join(externalGsd, "activity"), { recursive: true });
+		symlinkSync(externalGsd, join(repo, ".sf"));
+		writeFileSync(join(repo, ".gitignore"), ".sf\n");
+		createFile(repo, "cmd/installer/main.go", "package main\n");
+		run("git add -A", repo);
+		run('git commit -m "add installer"', repo);
+
+		writeFileSync(
+			join(repo, "cmd/installer/main.go"),
+			"package main\n// edit\n",
+		);
+		createFile(repo, "cmd/installer/main_test.go", "package main\n");
+		createFile(repo, "data/large-model.bin", "pretend this is 10GB");
+
+		const svc = new GitServiceImpl(repo);
+		assert.equal(
+			svc.stageOnly([], ["cmd/installer/main_test.go"]),
+			true,
+			"explicit task output should make stageOnly see staged changes",
+		);
+
+		const staged = run("git diff --cached --name-only", repo);
+		assert.ok(staged.includes("cmd/installer/main.go"));
+		assert.ok(
+			staged.includes("cmd/installer/main_test.go"),
+			"explicit untracked task file should be staged despite symlink fallback",
+		);
+		assert.ok(
+			!staged.includes("data/large-model.bin"),
+			"unlisted untracked files stay unstaged",
+		);
+
+		rmSync(repo, { recursive: true, force: true });
+		rmSync(externalGsd, { recursive: true, force: true });
+	});
+
 	// ─── nativeAddAllWithExclusions: non-symlinked .sf still works ───────
 
 	test("nativeAddAllWithExclusions: non-symlinked .sf still works", () => {