diff --git a/tests/test_build_workflow.py b/tests/test_build_workflow.py
index e2897640..771c0826 100644
--- a/tests/test_build_workflow.py
+++ b/tests/test_build_workflow.py
@@ -1,3 +1,4 @@
+import json
 import shutil
 import subprocess
 from pathlib import Path
@@ -209,7 +210,8 @@ def test_queued_build_uses_harness_prompt_and_records_build_operation(
     assert adapter.requests[0].agent is HarnessAgentKind.BUILD
     assert adapter.requests[0].prompt.startswith("Runtime context:\n{")
     assert "Build Operation" not in adapter.requests[0].prompt
-    assert f'"manual_root": "{repo}/almanac/manual"' in adapter.requests[0].prompt
+    manual_root = json.dumps(str(repo / "almanac" / "manual"))
+    assert f'"manual_root": {manual_root}' in adapter.requests[0].prompt
     assert '"manual_documents"' not in adapter.requests[0].prompt
     assert "Write the smallest useful first wiki." in adapter.requests[0].prompt
 
diff --git a/tests/test_tagging.py b/tests/test_tagging.py
index b4f121f9..438550e4 100644
--- a/tests/test_tagging.py
+++ b/tests/test_tagging.py
@@ -15,6 +15,7 @@ def test_tag_adds_topic_preserves_body_and_frontmatter_comment(
     page.write_text(
         f"---\ntitle: Auth Flow\n# keep this comment\ntopics: [auth]\n---\n{body}",
         encoding="utf-8",
+        newline="",
     )
     app = create_app(
         AppConfig(database_path=isolated_home / ".codealmanac/codealmanac.db")
@@ -43,6 +44,7 @@ def test_untag_removes_topic_and_allows_orphan_page(
     page.write_text(
         "---\ntitle: Auth Flow\ntopics: [auth]\n---\n# Auth Flow\n",
         encoding="utf-8",
+        newline="",
     )
     app = create_app(
         AppConfig(database_path=isolated_home / ".codealmanac/codealmanac.db")
@@ -63,7 +65,7 @@ def test_tag_adds_frontmatter_when_page_has_none(
 ):
     repo = make_repo(tmp_path)
     page = repo / "almanac/note.md"
-    page.write_text("# Note\n\nBody.\n", encoding="utf-8")
+    page.write_text("# Note\n\nBody.\n", encoding="utf-8", newline="")
     app = create_app(
         AppConfig(database_path=isolated_home / ".codealmanac/codealmanac.db")
     )
@@ -81,7 +83,7 @@ def test_tag_handles_frontmatter_closing_fence_at_eof(
 ):
     repo = make_repo(tmp_path)
     page = repo / "almanac/note.md"
-    page.write_text("---\ntitle: Note\n---", encoding="utf-8")
+    page.write_text("---\ntitle: Note\n---", encoding="utf-8", newline="")
     app = create_app(
         AppConfig(database_path=isolated_home / ".codealmanac/codealmanac.db")
     )
@@ -104,6 +106,7 @@ def test_tag_preserves_crlf_frontmatter_and_body(
     page.write_text(
         f"---\r\ntitle: Auth Flow\r\ntopics:\r\n  - auth\r\n---\r\n{body}",
         encoding="utf-8",
+        newline="",
     )
     app = create_app(
         AppConfig(database_path=isolated_home / ".codealmanac/codealmanac.db")
diff --git a/tests/test_transcript_discovery.py b/tests/test_transcript_discovery.py
index a6a4288b..24ed1257 100644
--- a/tests/test_transcript_discovery.py
+++ b/tests/test_transcript_discovery.py
@@ -73,13 +73,13 @@ def test_claude_transcript_discovery_reads_metadata_and_skips_subagents(
     projects.mkdir(parents=True)
     transcript = projects / "session.jsonl"
     transcript.write_text(
-        f'{{"sessionId":"claude-1","cwd":"{repo}"}}\n',
+        json.dumps({"sessionId": "claude-1", "cwd": str(repo)}) + "\n",
         encoding="utf-8",
     )
     subagents = projects / "subagents"
     subagents.mkdir()
     (subagents / "session.jsonl").write_text(
-        f'{{"sessionId":"claude-2","cwd":"{repo}"}}\n',
+        json.dumps({"sessionId": "claude-2", "cwd": str(repo)}) + "\n",
         encoding="utf-8",
     )