diff --git a/.github/workflows/_test.yml b/.github/workflows/_test.yml
index 53ecb358..556fbbf2 100644
--- a/.github/workflows/_test.yml
+++ b/.github/workflows/_test.yml
@@ -88,6 +88,18 @@ jobs:
         env:
           CBM_SKIP_PERF: ${{ inputs.skip_perf && '1' || '' }}
 
+  test-tsan:
+    runs-on: ubuntu-latest
+    timeout-minutes: 120
+    steps:
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+
+      - name: Install deps (Ubuntu)
+        run: sudo apt-get update && sudo apt-get install -y clang zlib1g-dev
+
+      - name: ThreadSanitizer tests
+        run: make -f Makefile.cbm test-tsan CC=clang CXX=clang++
+
   test-windows:
     needs: setup-matrix
     strategy:
diff --git a/Makefile.cbm b/Makefile.cbm
index 299cfcde..d9c0218b 100644
--- a/Makefile.cbm
+++ b/Makefile.cbm
@@ -67,10 +67,11 @@ CFLAGS_TEST = $(CFLAGS_COMMON) -g -O1 $(SANITIZE)
 CXXFLAGS_TEST = $(CXXFLAGS_COMMON) -g -O1 $(SANITIZE)
 
 # TSan (can't combine with ASan)
+TSAN_SANITIZE = -fsanitize=thread -fno-omit-frame-pointer
 CFLAGS_TSAN = $(CFLAGS_COMMON) -g -O1 \
-              -fsanitize=thread -fno-omit-frame-pointer
+              $(TSAN_SANITIZE)
 CXXFLAGS_TSAN = $(CXXFLAGS_COMMON) -g -O1 \
-                -fsanitize=thread -fno-omit-frame-pointer
+                $(TSAN_SANITIZE)
 
 # Windows needs ws2_32 (Winsock), psapi (GetProcessMemoryInfo), and
 # --allow-multiple-definition (MinGW CRT symbol clashes).
@@ -88,7 +89,7 @@ endif
 
 LDFLAGS = -lm -lstdc++ -lpthread -lz $(WIN32_LIBS) $(STATIC_FLAGS)
 LDFLAGS_TEST = -lm -lstdc++ -lpthread -lz $(SANITIZE) $(WIN32_LIBS)
-LDFLAGS_TSAN = -lm -lstdc++ -lpthread -lz -fsanitize=thread $(WIN32_LIBS)
+LDFLAGS_TSAN = -lm -lstdc++ -lpthread -lz $(TSAN_SANITIZE) $(WIN32_LIBS)
 
 # ── Source files ─────────────────────────────────────────────────
 
@@ -480,13 +481,17 @@ GRAMMAR_CFLAGS = -std=c11 -D_DEFAULT_SOURCE -O2 -w -I$(CBM_DIR) -I$(TS_INCLUDE)
 GRAMMAR_CFLAGS_TEST = -std=c11 -D_DEFAULT_SOURCE -g -O1 -w -I$(CBM_DIR) -I$(TS_INCLUDE) -I$(TS_SRC) \
                       $(SANITIZE)
 GRAMMAR_CFLAGS_TSAN = -std=c11 -D_DEFAULT_SOURCE -g -O1 -w -I$(CBM_DIR) -I$(TS_INCLUDE) -I$(TS_SRC) \
-                      -fsanitize=thread -fno-omit-frame-pointer
+                      $(TSAN_SANITIZE)
 
 # Object files for grammars + ts_runtime + lsp_all + preprocessor
 GRAMMAR_OBJS_TEST = $(patsubst $(CBM_DIR)/%.c,$(BUILD_DIR)/%.o,$(GRAMMAR_SRCS))
 TS_RUNTIME_OBJ_TEST = $(BUILD_DIR)/ts_runtime.o
 LSP_OBJ_TEST = $(BUILD_DIR)/lsp_all.o
 PP_OBJ_TEST = $(BUILD_DIR)/preprocessor.o
+GRAMMAR_OBJS_TSAN = $(patsubst $(CBM_DIR)/%.c,$(BUILD_DIR)/tsan_%.o,$(GRAMMAR_SRCS))
+TS_RUNTIME_OBJ_TSAN = $(BUILD_DIR)/tsan_ts_runtime.o
+LSP_OBJ_TSAN = $(BUILD_DIR)/tsan_lsp_all.o
+PP_OBJ_TSAN = $(BUILD_DIR)/tsan_preprocessor.o
 
 # ── Targets ──────────────────────────────────────────────────────
 
@@ -517,53 +522,86 @@ $(BUILD_DIR)/lsp_all.o: $(LSP_UNITY_DEPS) | $(BUILD_DIR)
 $(BUILD_DIR)/preprocessor.o: $(CBM_DIR)/preprocessor.cpp | $(BUILD_DIR)
 	$(CXX) $(CXXFLAGS_TEST) -w -I$(CBM_DIR)/vendored -c -o $@ $<
 
+$(BUILD_DIR)/tsan_%.o: $(CBM_DIR)/%.c | $(BUILD_DIR)
+	$(CC) $(GRAMMAR_CFLAGS_TSAN) -c -o $@ $<
+
+$(BUILD_DIR)/tsan_ts_runtime.o: $(CBM_DIR)/ts_runtime.c | $(BUILD_DIR)
+	$(CC) $(GRAMMAR_CFLAGS_TSAN) -c -o $@ $<
+
+$(BUILD_DIR)/tsan_lsp_all.o: $(LSP_UNITY_DEPS) | $(BUILD_DIR)
+	$(CC) $(GRAMMAR_CFLAGS_TSAN) -c -o $@ $<
+
+$(BUILD_DIR)/tsan_preprocessor.o: $(CBM_DIR)/preprocessor.cpp | $(BUILD_DIR)
+	$(CXX) $(CXXFLAGS_TSAN) -w -I$(CBM_DIR)/vendored -c -o $@ $<
+
 # ── Full test binary ─────────────────────────────────────────────
 
 # mimalloc object files
 MIMALLOC_OBJ_TEST = $(BUILD_DIR)/mimalloc.o
+MIMALLOC_OBJ_TSAN = $(BUILD_DIR)/tsan_mimalloc.o
 MIMALLOC_OBJ_PROD = $(BUILD_DIR)/prod_mimalloc.o
 
 $(BUILD_DIR)/mimalloc.o: $(MIMALLOC_SRC) | $(BUILD_DIR)
 	$(CC) $(MIMALLOC_CFLAGS_TEST) -c -o $@ $<
 
+$(BUILD_DIR)/tsan_mimalloc.o: $(MIMALLOC_SRC) | $(BUILD_DIR)
+	$(CC) $(MIMALLOC_CFLAGS_TEST) $(TSAN_SANITIZE) -c -o $@ $<
+
 $(BUILD_DIR)/prod_mimalloc.o: $(MIMALLOC_SRC) | $(BUILD_DIR)
 	$(CC) $(MIMALLOC_CFLAGS) -c -o $@ $<
 
 # sqlite3 object files (vendored amalgamation)
 SQLITE3_OBJ_TEST = $(BUILD_DIR)/sqlite3.o
+SQLITE3_OBJ_TSAN = $(BUILD_DIR)/tsan_sqlite3.o
 SQLITE3_OBJ_PROD = $(BUILD_DIR)/prod_sqlite3.o
 
 $(BUILD_DIR)/sqlite3.o: $(SQLITE3_SRC) | $(BUILD_DIR)
 	$(CC) $(SQLITE3_CFLAGS_TEST) $(SANITIZE) -c -o $@ $<
 
+$(BUILD_DIR)/tsan_sqlite3.o: $(SQLITE3_SRC) | $(BUILD_DIR)
+	$(CC) $(SQLITE3_CFLAGS_TEST) $(TSAN_SANITIZE) -c -o $@ $<
+
 $(BUILD_DIR)/prod_sqlite3.o: $(SQLITE3_SRC) | $(BUILD_DIR)
 	$(CC) $(SQLITE3_CFLAGS) -c -o $@ $<
 
 # TRE regex (only compiled on Windows — POSIX uses system <regex.h>)
 TRE_OBJ_TEST :=
+TRE_OBJ_TSAN :=
 TRE_OBJ_PROD :=
 ifeq ($(IS_MINGW),yes)
 TRE_OBJ_TEST = $(BUILD_DIR)/tre.o
+TRE_OBJ_TSAN = $(BUILD_DIR)/tsan_tre.o
 TRE_OBJ_PROD = $(BUILD_DIR)/prod_tre.o
 
 $(BUILD_DIR)/tre.o: $(TRE_SRC) | $(BUILD_DIR)
 	$(CC) $(TRE_CFLAGS) $(SANITIZE) -fno-sanitize=alignment -c -o $@ $<
 
+$(BUILD_DIR)/tsan_tre.o: $(TRE_SRC) | $(BUILD_DIR)
+	$(CC) $(TRE_CFLAGS) $(TSAN_SANITIZE) -c -o $@ $<
+
 $(BUILD_DIR)/prod_tre.o: $(TRE_SRC) | $(BUILD_DIR)
 	$(CC) $(TRE_CFLAGS) -O2 -c -o $@ $<
 endif
 
 # Vendored LZ4 (test build)
 LZ4_OBJ_TEST = $(BUILD_DIR)/test_lz4.o $(BUILD_DIR)/test_lz4hc.o
+LZ4_OBJ_TSAN = $(BUILD_DIR)/tsan_lz4.o $(BUILD_DIR)/tsan_lz4hc.o
 $(BUILD_DIR)/test_lz4.o: $(CBM_DIR)/vendored/lz4/lz4.c | $(BUILD_DIR)
 	$(CC) -std=c11 -D_DEFAULT_SOURCE -g -O1 $(SANITIZE) -w -I$(CBM_DIR) -c -o $@ $<
 $(BUILD_DIR)/test_lz4hc.o: $(CBM_DIR)/vendored/lz4/lz4hc.c | $(BUILD_DIR)
 	$(CC) -std=c11 -D_DEFAULT_SOURCE -g -O1 $(SANITIZE) -w -I$(CBM_DIR)/vendored/lz4 -c -o $@ $<
+$(BUILD_DIR)/tsan_lz4.o: $(CBM_DIR)/vendored/lz4/lz4.c | $(BUILD_DIR)
+	$(CC) -std=c11 -D_DEFAULT_SOURCE -g -O1 $(TSAN_SANITIZE) -w -I$(CBM_DIR) -c -o $@ $<
+$(BUILD_DIR)/tsan_lz4hc.o: $(CBM_DIR)/vendored/lz4/lz4hc.c | $(BUILD_DIR)
+	$(CC) -std=c11 -D_DEFAULT_SOURCE -g -O1 $(TSAN_SANITIZE) -w -I$(CBM_DIR)/vendored/lz4 -c -o $@ $<
 
 # Vendored zstd (test build)
 ZSTD_OBJ_TEST = $(BUILD_DIR)/test_zstd.o
+ZSTD_OBJ_TSAN = $(BUILD_DIR)/tsan_zstd.o
 $(BUILD_DIR)/test_zstd.o: $(CBM_DIR)/vendored/zstd/zstd.c | $(BUILD_DIR)
 	$(CC) -std=c11 -D_DEFAULT_SOURCE -g -O1 $(SANITIZE) -w -I$(CBM_DIR)/vendored/zstd -c -o $@ $<
+$(BUILD_DIR)/tsan_zstd.o: $(CBM_DIR)/vendored/zstd/zstd.c | $(BUILD_DIR)
+	$(CC) -std=c11 -D_DEFAULT_SOURCE -g -O1 $(TSAN_SANITIZE) -w -I$(CBM_DIR)/vendored/zstd -c -o $@ $<
 
 # nomic-embed-code pretrained vector blob
 UNIXCODER_OBJ = $(BUILD_DIR)/unixcoder_blob.o
@@ -571,6 +609,7 @@ $(UNIXCODER_OBJ): $(UNIXCODER_BLOB_SRC) vendored/nomic/code_vectors.bin | $(BUIL
 	$(CC) -c -o $@ $<
 
 OBJS_VENDORED_TEST = $(MIMALLOC_OBJ_TEST) $(SQLITE3_OBJ_TEST) $(TRE_OBJ_TEST) $(GRAMMAR_OBJS_TEST) $(TS_RUNTIME_OBJ_TEST) $(LSP_OBJ_TEST) $(PP_OBJ_TEST) $(LZ4_OBJ_TEST) $(ZSTD_OBJ_TEST) $(UNIXCODER_OBJ)
+OBJS_VENDORED_TSAN = $(MIMALLOC_OBJ_TSAN) $(SQLITE3_OBJ_TSAN) $(TRE_OBJ_TSAN) $(GRAMMAR_OBJS_TSAN) $(TS_RUNTIME_OBJ_TSAN) $(LSP_OBJ_TSAN) $(PP_OBJ_TSAN) $(LZ4_OBJ_TSAN) $(ZSTD_OBJ_TSAN) $(UNIXCODER_OBJ)
 
 $(BUILD_DIR)/test-runner: $(ALL_TEST_SRCS) $(PROD_SRCS) $(EXTRACTION_SRCS) $(AC_LZ4_SRCS) $(ZSTD_SRCS) $(SQLITE_WRITER_SRC) $(OBJS_VENDORED_TEST) | $(BUILD_DIR)
 	$(CC) $(CFLAGS_TEST) -Itests -Itests/repro -o $@ \
@@ -598,8 +637,18 @@ test-repro: $(BUILD_DIR)/test-repro-runner
 
 # ── TSan full test ───────────────────────────────────────────────
 
-test-tsan:
-	@echo "TSan not yet wired for full extraction tests"
+TEST_TSAN_SUITES ?= mem slab_alloc parallel
+TSAN_OPTIONS ?= halt_on_error=1
+
+$(BUILD_DIR)/test-runner-tsan: $(ALL_TEST_SRCS) $(PROD_SRCS) $(EXTRACTION_SRCS) $(AC_LZ4_SRCS) $(ZSTD_SRCS) $(SQLITE_WRITER_SRC) $(OBJS_VENDORED_TSAN) | $(BUILD_DIR)
+	$(CC) $(CFLAGS_TSAN) -Itests -Itests/repro -o $@ \
+		$(ALL_TEST_SRCS) $(PROD_SRCS) \
+		$(EXTRACTION_SRCS) $(AC_LZ4_SRCS) $(ZSTD_SRCS) $(SQLITE_WRITER_SRC) \
+		$(OBJS_VENDORED_TSAN) \
+		$(LDFLAGS_TSAN)
+
+test-tsan: $(BUILD_DIR)/test-runner-tsan
+	cd $(CURDIR) && TSAN_OPTIONS="$(TSAN_OPTIONS)" $(BUILD_DIR)/test-runner-tsan $(TEST_TSAN_SUITES)
 
 # ── Production binary ────────────────────────────────────────────