diff --git a/src/headless.ts b/src/headless.ts
index 438972c3a..3a0d87fa9 100644
--- a/src/headless.ts
+++ b/src/headless.ts
@@ -723,6 +723,9 @@ async function runHeadlessOnce(
 	let exitCode = 0;
 	let milestoneReady = false; // tracks "Milestone X ready." for auto-chaining
 	let timedOut = false; // true only when the overall timeout timer fires
+	// Rolling buffer for milestone-ready detection across split streaming deltas.
+	// Capped at 200 chars — long enough to bridge any realistic delta boundary.
+	let milestoneDetectionBuffer = "";
 	let providerAutoResumePending = false;
 	const recentEvents: TrackedEvent[] = [];
 	const interactiveToolCallIds = new Set<string>();
diff --git a/src/resources/extensions/sf/atomic-write.ts b/src/resources/extensions/sf/atomic-write.ts
index 84563c4ad..1356c46d6 100644
--- a/src/resources/extensions/sf/atomic-write.ts
+++ b/src/resources/extensions/sf/atomic-write.ts
@@ -161,7 +161,7 @@ export function atomicWriteSyncWithOps(
 	const tmpPath = ops.createTempPath?.(filePath) ?? defaultTempPath(filePath);
 	ops.writeFile(tmpPath, content, encoding);
 
-	let lastError: unknown = null;
+	const errors: unknown[] = [];
 	let attempts = 0;
 
 	for (attempts = 1; attempts <= MAX_RENAME_ATTEMPTS; attempts++) {
@@ -169,7 +169,7 @@ export function atomicWriteSyncWithOps(
 			ops.rename(tmpPath, filePath);
 			return;
 		} catch (error) {
-			lastError = error;
+			errors.push(error);
 			if (!isTransientLockError(error) || attempts === MAX_RENAME_ATTEMPTS) {
 				break;
 			}
@@ -178,7 +178,7 @@ export function atomicWriteSyncWithOps(
 	}
 
 	cleanupTempFileSync(tmpPath, ops);
-	throw buildAtomicWriteError(filePath, attempts, lastError);
+	throw buildAtomicWriteError(filePath, attempts, errors);
 }
 
 const DEFAULT_ASYNC_OPS: AtomicWriteAsyncOps = {
diff --git a/src/resources/extensions/sf/doctor-runtime-checks.ts b/src/resources/extensions/sf/doctor-runtime-checks.ts
index a99cefc16..be0f1dd8c 100644
--- a/src/resources/extensions/sf/doctor-runtime-checks.ts
+++ b/src/resources/extensions/sf/doctor-runtime-checks.ts
@@ -345,16 +345,8 @@ export async function checkRuntimeHealth(
 			);
 
 			// Check for critical runtime patterns that must be present.
-			// NOTE: SF_RUNTIME_PATTERNS in gitignore.ts is the canonical source of truth.
-			// This is a minimal subset for the doctor check.
-			const criticalPatterns = [
-				".sf/activity/",
-				".sf/runtime/",
-				".sf/auto.lock",
-				".sf/sf.db*",
-				".sf/completed-units*.json",
-				".sf/event-log.jsonl",
-			];
+			// Use the canonical SF_RUNTIME_PATTERNS list for consistency.
+			const criticalPatterns = Array.from(SF_RUNTIME_PATTERNS);
 
 			// If blanket .sf/ or .sf is present, all patterns are covered
 			const hasBlanketIgnore =
diff --git a/src/resources/extensions/sf/doctor.ts b/src/resources/extensions/sf/doctor.ts
index d2b56e7fd..428d75c00 100644
--- a/src/resources/extensions/sf/doctor.ts
+++ b/src/resources/extensions/sf/doctor.ts
@@ -637,6 +637,7 @@ export async function runSFDoctor(
 	const requirementsContent = await loadFile(requirementsPath);
 	issues.push(...auditRequirements(requirementsContent));
 
+	const t0state = Date.now();
 	const state = await deriveState(basePath);
 
 	// Provider / auth health checks — only relevant when there is active work to dispatch.
diff --git a/src/resources/extensions/sf/jsonl-utils.ts b/src/resources/extensions/sf/jsonl-utils.ts
index b7620c177..23017750f 100644
--- a/src/resources/extensions/sf/jsonl-utils.ts
+++ b/src/resources/extensions/sf/jsonl-utils.ts
@@ -11,6 +11,7 @@ export const MAX_JSONL_BYTES = 10 * 1024 * 1024; // 10 MB
 
 /**
  * Parse a raw JSONL string into an array of parsed objects.
+ *
  * If the input exceeds MAX_JSONL_BYTES, only the tail is parsed (most recent entries).
  */
 export function parseJSONL(raw: string): unknown[] {
diff --git a/src/resources/extensions/sf/self-feedback.ts b/src/resources/extensions/sf/self-feedback.ts
index 15e79ac30..3ec86ec98 100644
--- a/src/resources/extensions/sf/self-feedback.ts
+++ b/src/resources/extensions/sf/self-feedback.ts
@@ -236,7 +236,7 @@ function escapeCell(text: string): string {
 
 function readActiveUnit(basePath: string): SelfFeedbackOccurredIn | undefined {
 	try {
-		const lockPath = join(basePath, ".sf", "auto.lock");
+		const lockPath = join(sfRuntimeRoot(basePath), "auto.lock");
 		if (!existsSync(lockPath)) return undefined;
 		const lock = JSON.parse(readFileSync(lockPath, "utf-8"));
 		const id: string | undefined = lock?.unitId;
diff --git a/src/resources/extensions/sf/workflow-templates.ts b/src/resources/extensions/sf/workflow-templates.ts
index f5ff652c2..74b9116f4 100644
--- a/src/resources/extensions/sf/workflow-templates.ts
+++ b/src/resources/extensions/sf/workflow-templates.ts
@@ -133,6 +133,9 @@ export function loadRegistry(): TemplateRegistry {
  *
  * Consumer: `/sf` command completion catalogs and `/sf start` usage rendering.
  */
+/**
+ * Get registry-backed command definitions for /sf start completion and help.
+ */
 export function workflowTemplateCommandDefinitions(): WorkflowTemplateCommandDefinition[] {
 	const registry = loadRegistry();
 	return Object.entries(registry.templates).map(([id, entry]) => ({
diff --git a/src/resources/extensions/sf/worktree-resolver.ts b/src/resources/extensions/sf/worktree-resolver.ts
index 43f60cde6..e853e75e5 100644
--- a/src/resources/extensions/sf/worktree-resolver.ts
+++ b/src/resources/extensions/sf/worktree-resolver.ts
@@ -620,11 +620,13 @@ export class WorktreeResolver {
 			);
 
 			// Clean up stale merge state left by failed squash-merge (#1389)
-			// Use resolveGitDir to handle worktrees where .git is a file (gitdir pointer)
+			// Use resolveGitDir to handle worktrees where .git is a file (gitdir pointer).
+			// Use resolve() rather than join() to normalise any backslash separators on
+			// Windows and avoid mixed-separator paths in downstream comparisons.
 			try {
 				const gitDir = resolveGitDir(originalBase || this.s.basePath);
 				for (const f of ["SQUASH_MSG", "MERGE_HEAD", "MERGE_MSG"]) {
-					const p = join(gitDir, f);
+					const p = resolve(gitDir, f);
 					if (existsSync(p)) unlinkSync(p);
 				}
 			} catch {