diff --git a/README.md b/README.md
index 0bd7849..a3932d8 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,10 @@
 
 `prec` is a Linux command execution observability tool where `precd` uses eBPF to continuously collect process execution events as JSON Lines and `prec` lets you quickly search and inspect those records from the CLI.
 
+Implementation note:
+
+- Go packages under `internal/` are private implementation details and are not a supported public import API
+
 ## Why use it
 
 - Does not rely on shell history or `LD_PRELOAD`
diff --git a/cmd/prec/main.go b/cmd/prec/main.go
index 7527621..cee89ed 100644
--- a/cmd/prec/main.go
+++ b/cmd/prec/main.go
@@ -7,7 +7,7 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/jfut/prec/pkg/cli"
+	"github.com/jfut/prec/internal/cli"
 )
 
 // Build metadata fields are injected by linker flags at build time.
diff --git a/cmd/precd/main.go b/cmd/precd/main.go
index a2d6289..ccf1f0f 100644
--- a/cmd/precd/main.go
+++ b/cmd/precd/main.go
@@ -13,9 +13,9 @@ import (
 
 	"github.com/alecthomas/kong"
 
-	"github.com/jfut/prec/pkg/collector"
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/logger"
+	"github.com/jfut/prec/internal/collector"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/logger"
 )
 
 // Build metadata fields are injected by linker flags at build time.
diff --git a/pkg/cli/app.go b/internal/cli/app.go
similarity index 98%
rename from pkg/cli/app.go
rename to internal/cli/app.go
index 0c8bfb0..f1602ed 100644
--- a/pkg/cli/app.go
+++ b/internal/cli/app.go
@@ -11,8 +11,8 @@ import (
 
 	"github.com/alecthomas/kong"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/query"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/query"
 )
 
 type listFilter struct {
diff --git a/pkg/cli/app_test.go b/internal/cli/app_test.go
similarity index 99%
rename from pkg/cli/app_test.go
rename to internal/cli/app_test.go
index eb68386..7cf9371 100644
--- a/pkg/cli/app_test.go
+++ b/internal/cli/app_test.go
@@ -15,7 +15,7 @@ import (
 
 	"github.com/alecthomas/kong"
 
-	"github.com/jfut/prec/pkg/config"
+	"github.com/jfut/prec/internal/config"
 )
 
 func TestValidateModeFlags(t *testing.T) {
diff --git a/pkg/cli/constants.go b/internal/cli/constants.go
similarity index 100%
rename from pkg/cli/constants.go
rename to internal/cli/constants.go
diff --git a/pkg/cli/event_collection.go b/internal/cli/event_collection.go
similarity index 99%
rename from pkg/cli/event_collection.go
rename to internal/cli/event_collection.go
index bb25795..a5174c6 100644
--- a/pkg/cli/event_collection.go
+++ b/internal/cli/event_collection.go
@@ -15,7 +15,7 @@ import (
 	"github.com/klauspost/compress/gzip"
 	"github.com/klauspost/compress/zstd"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func collectFilteredEvents(logPaths []string, limit int, lf listFilter) ([]events.CommandEvent, error) {
diff --git a/pkg/cli/event_collection_test.go b/internal/cli/event_collection_test.go
similarity index 99%
rename from pkg/cli/event_collection_test.go
rename to internal/cli/event_collection_test.go
index 39ca6e5..a20d005 100644
--- a/pkg/cli/event_collection_test.go
+++ b/internal/cli/event_collection_test.go
@@ -7,7 +7,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestCollectFilteredEventsAcrossRotatedLogs(t *testing.T) {
diff --git a/pkg/cli/event_merge.go b/internal/cli/event_merge.go
similarity index 98%
rename from pkg/cli/event_merge.go
rename to internal/cli/event_merge.go
index 2e8ac81..836a6f6 100644
--- a/pkg/cli/event_merge.go
+++ b/internal/cli/event_merge.go
@@ -3,7 +3,7 @@
 
 package cli
 
-import "github.com/jfut/prec/pkg/events"
+import "github.com/jfut/prec/internal/events"
 
 type commandJoinState struct {
 	pending map[string]events.CommandEvent
diff --git a/pkg/cli/event_merge_test.go b/internal/cli/event_merge_test.go
similarity index 99%
rename from pkg/cli/event_merge_test.go
rename to internal/cli/event_merge_test.go
index 6e74080..71c3a74 100644
--- a/pkg/cli/event_merge_test.go
+++ b/internal/cli/event_merge_test.go
@@ -6,7 +6,7 @@ package cli
 import (
 	"testing"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestMergeEventsForListJoinsStartEnd(t *testing.T) {
diff --git a/pkg/cli/log_paths.go b/internal/cli/log_paths.go
similarity index 100%
rename from pkg/cli/log_paths.go
rename to internal/cli/log_paths.go
diff --git a/pkg/cli/log_paths_test.go b/internal/cli/log_paths_test.go
similarity index 100%
rename from pkg/cli/log_paths_test.go
rename to internal/cli/log_paths_test.go
diff --git a/pkg/cli/log_reader.go b/internal/cli/log_reader.go
similarity index 100%
rename from pkg/cli/log_reader.go
rename to internal/cli/log_reader.go
diff --git a/pkg/cli/log_reader_test.go b/internal/cli/log_reader_test.go
similarity index 98%
rename from pkg/cli/log_reader_test.go
rename to internal/cli/log_reader_test.go
index 8c1dfd4..1581637 100644
--- a/pkg/cli/log_reader_test.go
+++ b/internal/cli/log_reader_test.go
@@ -10,8 +10,8 @@ import (
 	"sync"
 	"testing"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestOpenLogReaderDetectsCompressionByMagic(t *testing.T) {
diff --git a/pkg/cli/output_formatter.go b/internal/cli/output_formatter.go
similarity index 99%
rename from pkg/cli/output_formatter.go
rename to internal/cli/output_formatter.go
index 00e56ac..9127775 100644
--- a/pkg/cli/output_formatter.go
+++ b/internal/cli/output_formatter.go
@@ -13,7 +13,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 // outputFormatter hides per-format encoding details from list/follow flows.
diff --git a/pkg/cli/output_formatter_test.go b/internal/cli/output_formatter_test.go
similarity index 99%
rename from pkg/cli/output_formatter_test.go
rename to internal/cli/output_formatter_test.go
index c1975e1..87022b8 100644
--- a/pkg/cli/output_formatter_test.go
+++ b/internal/cli/output_formatter_test.go
@@ -8,7 +8,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestFormatEventSimple(t *testing.T) {
diff --git a/pkg/cli/query_filter.go b/internal/cli/query_filter.go
similarity index 89%
rename from pkg/cli/query_filter.go
rename to internal/cli/query_filter.go
index e3b31ca..11ee8c1 100644
--- a/pkg/cli/query_filter.go
+++ b/internal/cli/query_filter.go
@@ -4,8 +4,8 @@
 package cli
 
 import (
-	"github.com/jfut/prec/pkg/events"
-	"github.com/jfut/prec/pkg/query"
+	"github.com/jfut/prec/internal/events"
+	"github.com/jfut/prec/internal/query"
 )
 
 func buildQueryFilter(specs []string) (listFilter, error) {
diff --git a/pkg/cli/query_filter_test.go b/internal/cli/query_filter_test.go
similarity index 99%
rename from pkg/cli/query_filter_test.go
rename to internal/cli/query_filter_test.go
index cea3833..4431b6f 100644
--- a/pkg/cli/query_filter_test.go
+++ b/internal/cli/query_filter_test.go
@@ -7,7 +7,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestBuildQueryFilterValid(t *testing.T) {
diff --git a/pkg/cli/tail.go b/internal/cli/tail.go
similarity index 99%
rename from pkg/cli/tail.go
rename to internal/cli/tail.go
index 25064df..0421216 100644
--- a/pkg/cli/tail.go
+++ b/internal/cli/tail.go
@@ -13,7 +13,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func runList(logPaths []string, limit int, lf listFilter, opt outputOptions) int {
diff --git a/pkg/cli/test_helpers_test.go b/internal/cli/test_helpers_test.go
similarity index 99%
rename from pkg/cli/test_helpers_test.go
rename to internal/cli/test_helpers_test.go
index b3e7a45..89e8501 100644
--- a/pkg/cli/test_helpers_test.go
+++ b/internal/cli/test_helpers_test.go
@@ -15,7 +15,7 @@ import (
 
 	"github.com/klauspost/compress/zstd"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 func intPtr(v int) *int {
diff --git a/pkg/collector/collector_linux.go b/internal/collector/collector_linux.go
similarity index 99%
rename from pkg/collector/collector_linux.go
rename to internal/collector/collector_linux.go
index ac3a3db..d9a42a8 100644
--- a/pkg/collector/collector_linux.go
+++ b/internal/collector/collector_linux.go
@@ -24,10 +24,10 @@ import (
 	"github.com/cilium/ebpf/rlimit"
 	"golang.org/x/sys/unix"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
-	"github.com/jfut/prec/pkg/filter"
-	"github.com/jfut/prec/pkg/logger"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
+	"github.com/jfut/prec/internal/filter"
+	"github.com/jfut/prec/internal/logger"
 )
 
 const (
diff --git a/pkg/collector/collector_linux_test.go b/internal/collector/collector_linux_test.go
similarity index 98%
rename from pkg/collector/collector_linux_test.go
rename to internal/collector/collector_linux_test.go
index c8e2ee6..dd75c89 100644
--- a/pkg/collector/collector_linux_test.go
+++ b/internal/collector/collector_linux_test.go
@@ -16,9 +16,9 @@ import (
 	"testing"
 
 	"github.com/cilium/ebpf/asm"
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
-	"github.com/jfut/prec/pkg/logger"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
+	"github.com/jfut/prec/internal/logger"
 )
 
 func TestParseOffsetFromFormat(t *testing.T) {
diff --git a/pkg/config/config.go b/internal/config/config.go
similarity index 100%
rename from pkg/config/config.go
rename to internal/config/config.go
diff --git a/pkg/config/config_test.go b/internal/config/config_test.go
similarity index 100%
rename from pkg/config/config_test.go
rename to internal/config/config_test.go
diff --git a/pkg/events/event.go b/internal/events/event.go
similarity index 100%
rename from pkg/events/event.go
rename to internal/events/event.go
diff --git a/pkg/events/event_json.go b/internal/events/event_json.go
similarity index 100%
rename from pkg/events/event_json.go
rename to internal/events/event_json.go
diff --git a/pkg/events/event_test.go b/internal/events/event_test.go
similarity index 100%
rename from pkg/events/event_test.go
rename to internal/events/event_test.go
diff --git a/pkg/events/source.go b/internal/events/source.go
similarity index 100%
rename from pkg/events/source.go
rename to internal/events/source.go
diff --git a/pkg/events/source_test.go b/internal/events/source_test.go
similarity index 100%
rename from pkg/events/source_test.go
rename to internal/events/source_test.go
diff --git a/pkg/filter/filter.go b/internal/filter/filter.go
similarity index 93%
rename from pkg/filter/filter.go
rename to internal/filter/filter.go
index 1e167ef..16c8ac8 100644
--- a/pkg/filter/filter.go
+++ b/internal/filter/filter.go
@@ -7,9 +7,9 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
-	"github.com/jfut/prec/pkg/query"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
+	"github.com/jfut/prec/internal/query"
 )
 
 type compiledRule struct {
diff --git a/pkg/filter/filter_test.go b/internal/filter/filter_test.go
similarity index 96%
rename from pkg/filter/filter_test.go
rename to internal/filter/filter_test.go
index 4213d5e..3d3d060 100644
--- a/pkg/filter/filter_test.go
+++ b/internal/filter/filter_test.go
@@ -6,8 +6,8 @@ package filter
 import (
 	"testing"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestMatcherRulesFirstMatchWins(t *testing.T) {
diff --git a/pkg/logger/jsonl.go b/internal/logger/jsonl.go
similarity index 98%
rename from pkg/logger/jsonl.go
rename to internal/logger/jsonl.go
index 082bec4..3176eb6 100644
--- a/pkg/logger/jsonl.go
+++ b/internal/logger/jsonl.go
@@ -16,8 +16,8 @@ import (
 	"github.com/klauspost/compress/gzip"
 	"github.com/klauspost/compress/zstd"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
 )
 
 // JSONLWriter appends events line by line to a root-owned log file.
diff --git a/pkg/logger/jsonl_test.go b/internal/logger/jsonl_test.go
similarity index 97%
rename from pkg/logger/jsonl_test.go
rename to internal/logger/jsonl_test.go
index 38986d8..f4be4aa 100644
--- a/pkg/logger/jsonl_test.go
+++ b/internal/logger/jsonl_test.go
@@ -15,8 +15,8 @@ import (
 	"github.com/klauspost/compress/gzip"
 	"github.com/klauspost/compress/zstd"
 
-	"github.com/jfut/prec/pkg/config"
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/config"
+	"github.com/jfut/prec/internal/events"
 )
 
 func TestJSONLWriterReopenSwitchesOutputFile(t *testing.T) {
diff --git a/pkg/query/filter.go b/internal/query/filter.go
similarity index 99%
rename from pkg/query/filter.go
rename to internal/query/filter.go
index 98ac16a..29abd31 100644
--- a/pkg/query/filter.go
+++ b/internal/query/filter.go
@@ -12,7 +12,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/jfut/prec/pkg/events"
+	"github.com/jfut/prec/internal/events"
 )
 
 var operators = []string{"!~=", ">=", "<=", "!=", "~=", ">", "<", "="}
diff --git a/justfile b/justfile
index 39ccabc..98d347a 100644
--- a/justfile
+++ b/justfile
@@ -45,7 +45,7 @@ deps:
 #
 
 fmt:
-    gofmt -w ./cmd ./pkg
+    gofmt -w .
 
 lint:
     golangci-lint run ./...