Measure the compactor with a probe run

onechat probe LOG COUNT appends the first COUNT messages of a log to a
new chat in probe/ in the data directory and builds its tree with real
model calls, as the live check of the compactor. After each message it
waits for the builds, as a turn does. It reports the calls per message,
the cached share of the input tokens, the retries, the sizes of the
model lines, and the quota at the first and the last call.

The run guards the quota of the account: it stops at the first failed
call, so a wrong setting cannot repeat a failing call at each message,
and it stops when the used percent of any quota window grows by more
than 15 points since the first call.

A test generates the probe log: 1,000 readable made-up messages about a
small bakery order system, with the mix of kinds and sizes of the
synthetic log of the core. It writes the log to a file when
ONECHAT_PROBE_LOG names one, and needs no network.

Issue: b14d537

diff --git a/README.rst b/README.rst
index fdcc0e0af17f1c70de0795242da868f4a67fe2e9..c74a815ee0387db961d3d4d1953b8280114d23e0 100644 (file)
--- a/README.rst
+++ b/README.rst
@@ -63,6 +63,25 @@ before they expire. The file belongs to OneChat only. Do not share it
 with the Codex CLI, because each program rotates the refresh token and
 logs the other out.
 
 with the Codex CLI, because each program rotates the refresh token and
 logs the other out.
 

+*******
+ Probe
+*******
+
+``onechat probe LOG COUNT`` measures the compactor on a log. It appends
+the first COUNT messages of LOG, one JSON object ``{"kind", "text"}`` on
+each line, to a new chat in ``probe/`` in the data directory, and builds
+its tree with real model calls. The calls use the quota of the account.
+The run stops at the first failed call, or when the used percent of a
+quota window grows by more than 15 points. At the end it reports the
+calls per message, the cached share of the input tokens, the retries,
+the line sizes, and the quota at the first and the last call.
+
+A test writes a generated log of readable made-up messages:
+
+.. code:: console
+
+   ONECHAT_PROBE_LOG=probe.jsonl go test -run TestProbeLogHasTheSyntheticMix
+

 *************
  Development
 *************
 *************
  Development
 *************

diff --git a/main.go b/main.go
index 9cd619a3cf8a1e207cfecfbbd331321b9fbe5977..a561c3755c8b19860a4665762adaf2b2e9f38fd2 100644 (file)
--- a/main.go
+++ b/main.go
@@ -33,6 +33,11 @@ func run() error {
                if err != nil {
                        return err
                }
                if err != nil {
                        return err
                }

+       case len(args) > 0 && args[0] == "probe":
+               err := probe(ctx, args[1:], os.Stdout)
+               if err != nil {
+                       return err
+               }

        default:
                return fmt.Errorf("unknown command %q", strings.Join(args, " "))
        }
        default:
                return fmt.Errorf("unknown command %q", strings.Join(args, " "))
        }

diff --git a/probe.go b/probe.go
new file mode 100644 (file)
index 0000000..acd4f6b
--- /dev/null
+++ b/probe.go
@@ -0,0 +1,376 @@
+package main
+
+import (
+       "bufio"
+       "context"
+       "encoding/json"
+       "errors"
+       "fmt"
+       "io"
+       "maps"
+       "os"
+       "path/filepath"
+       "slices"
+       "strconv"
+       "strings"
+       "time"
+)
+
+const (
+       // probeName is the agent name of a probe run. The cache key comes from
+       // it.
+       probeName = "Probe"
+
+       // probeQuotaLimit is how many points the used percent of a quota window
+       // can grow in a probe run before the run stops.
+       probeQuotaLimit = 15.0
+
+       // probeLineBytes is the most bytes of one line of a probe log.
+       probeLineBytes = 1 << 20
+)
+
+// probe runs "onechat probe LOG COUNT". It appends the first COUNT messages of
+// LOG, one JSON object {kind, text} per line, to a new chat in probe/ in the
+// data directory, and builds its tree with the real compactor. After each
+// message it waits for the builds, as a turn does. It stops at the first
+// failed call, or when the used percent of a quota window grows by more than
+// probeQuotaLimit points. At the end it reports the calls, the cached share,
+// the quota, the retries, and the line sizes.
+func probe(ctx context.Context, args []string, out io.Writer) error {
+       if len(args) != 2 {
+               return errors.New("usage: onechat probe LOG COUNT")
+       }
+
+       count, err := strconv.Atoi(args[1])
+       if err != nil || count <= 0 {
+               return fmt.Errorf("COUNT %q is not a positive number", args[1])
+       }
+
+       entries, err := readProbeLog(args[0], count)
+       if err != nil {
+               return err
+       }
+
+       dir, err := dataDir()
+       if err != nil {
+               return err
+       }
+
+       config, err := loadConfig(dir)
+       if err != nil {
+               return err
+       }
+
+       address, auth, err := modelEndpoint(config, dir)
+       if err != nil {
+               return err
+       }
+
+       root := filepath.Join(dir, "probe", time.Now().Format("20060102-150405"))
+       err = os.MkdirAll(root, 0o700)
+       if err != nil {
+               return fmt.Errorf("create probe directory: %w", err)
+       }
+
+       usagePath := filepath.Join(root, "usage.jsonl")
+       client := newClient(address, auth, "onechat-"+probeName, usagePath)
+       memory, err := openMemory(ctx, root, time.Now, newCompactor(client, probeName, config.Compactor))
+       if err != nil {
+               return err
+       }
+
+       _, err = fmt.Fprintf(out, "probe: %d messages into %s with %s at %s effort\n", len(entries), root, config.Compactor.Model, config.Compactor.Effort)
+       if err != nil {
+               return errors.Join(err, memory.Close())
+       }
+
+       appended, stop := runProbe(ctx, memory, entries, usagePath)
+       sizes, err := modelLines(memory)
+       err = errors.Join(err, memory.Close())
+       if err != nil {
+               return err
+       }
+
+       records, err := readUsageFile(usagePath)
+       if err != nil {
+               return err
+       }
+
+       return writeProbeReport(out, appended, stop, records, sizes)
+}
+
+// runProbe appends the entries and waits for the builds after each one. It
+// returns the number of messages appended and why the run stopped early, or
+// "" when it did not.
+func runProbe(ctx context.Context, memory *Memory, entries []probeEntry, usagePath string) (int, string) {
+       for n, entry := range entries {
+               _, err := memory.Append(entry.Kind, entry.Text)
+               if err == nil {
+                       err = memory.Wait(ctx)
+               }
+
+               if err != nil {
+                       return n, err.Error()
+               }
+
+               records, err := readUsageFile(usagePath)
+               if err != nil {
+                       return n + 1, err.Error()
+               }
+
+               reason := probeStop(records)
+               if reason != "" {
+                       return n + 1, reason
+               }
+       }
+
+       return len(entries), ""
+}
+
+// probeEntry is one message of a probe log.
+type probeEntry struct {
+       Kind string `json:"kind"`
+       Text string `json:"text"`
+}
+
+// readProbeLog reads the first count messages of the probe log at path.
+func readProbeLog(path string, count int) (entries []probeEntry, err error) {
+       file, err := os.Open(path)
+       if err != nil {
+               return nil, fmt.Errorf("open probe log: %w", err)
+       }
+
+       defer func() {
+               err = errors.Join(err, file.Close())
+       }()
+
+       scanner := bufio.NewScanner(file)
+       scanner.Buffer(make([]byte, 64*1024), probeLineBytes)
+       for len(entries) < count && scanner.Scan() {
+               var entry probeEntry
+               err = json.Unmarshal(scanner.Bytes(), &entry)
+               if err != nil {
+                       return nil, fmt.Errorf("probe log line %d: %w", len(entries)+1, err)
+               }
+
+               entries = append(entries, entry)
+       }
+
+       err = scanner.Err()
+       if err != nil {
+               return nil, fmt.Errorf("read probe log: %w", err)
+       }
+
+       if len(entries) < count {
+               return nil, fmt.Errorf("probe log has %d messages, fewer than %d", len(entries), count)
+       }
+
+       return entries, nil
+}
+
+// probeStop returns why a probe run must stop: a failed call, or a quota window
+// whose used percent grew by more than probeQuotaLimit points since the first
+// call. It returns "" when the run can go on.
+func probeStop(records []usageRecord) string {
+       for _, record := range records {
+               if record.Error != "" {
+                       return "call failed: " + record.Error
+               }
+       }
+
+       if len(records) == 0 {
+               return ""
+       }
+
+       first := usedPercents(records[0])
+       for name, used := range usedPercents(records[len(records)-1]) {
+               start, found := first[name]
+               if found && used-start > probeQuotaLimit {
+                       return fmt.Sprintf("%s grew from %g to %g", name, start, used)
+               }
+       }
+
+       return ""
+}
+
+// modelLines returns the sizes of the nodes that the model wrote, in tree
+// order. A node that fits its source with no model call is not one of them.
+func modelLines(memory *Memory) ([]int, error) {
+       memory.mutex.Lock()
+       defer memory.mutex.Unlock()
+
+       keys, err := memory.tree.Keys()
+       if err != nil {
+               return nil, err
+       }
+
+       var sizes []int
+       for _, key := range keys {
+               node, _, err := memory.tree.Node(key.level, key.index)
+               if err != nil {
+                       return nil, err
+               }
+
+               model, err := builtByModel(memory, key)
+               if err != nil {
+                       return nil, err
+               }
+
+               if model {
+                       sizes = append(sizes, node.Size)
+               }
+       }
+
+       return sizes, nil
+}
+
+// builtByModel tells if the node key needed a model call: a leaf whose source
+// is over nodeBytes, or a merge whose children do not fit in one node.
+func builtByModel(memory *Memory, key nodeKey) (bool, error) {
+       if key.level == 0 {
+               message, err := memory.log.Message(key.index)
+               if err != nil {
+                       return false, err
+               }
+
+               _, free := freeLeaf(message)
+
+               return !free, nil
+       }
+
+       left, right, err := memory.children(key)
+       if err != nil {
+               return false, err
+       }
+
+       _, free := freeMerge(left, right)
+
+       return !free, nil
+}
+
+// readUsageFile reads the records of usage.jsonl at path.
+func readUsageFile(path string) (records []usageRecord, err error) {
+       file, err := os.Open(path)
+       if errors.Is(err, os.ErrNotExist) {
+               return nil, nil
+       }
+
+       if err != nil {
+               return nil, fmt.Errorf("open usage file: %w", err)
+       }
+
+       defer func() {
+               err = errors.Join(err, file.Close())
+       }()
+
+       scanner := bufio.NewScanner(file)
+       scanner.Buffer(make([]byte, 64*1024), probeLineBytes)
+       for scanner.Scan() {
+               var record usageRecord
+               err = json.Unmarshal(scanner.Bytes(), &record)
+               if err != nil {
+                       return nil, fmt.Errorf("decode usage: %w", err)
+               }
+
+               records = append(records, record)
+       }
+
+       err = scanner.Err()
+       if err != nil {
+               return nil, fmt.Errorf("read usage file: %w", err)
+       }
+
+       return records, nil
+}
+
+// usedPercents returns the used percent of each quota window of record, by
+// header name.
+func usedPercents(record usageRecord) map[string]float64 {
+       used := make(map[string]float64)
+       for name, value := range record.Quota {
+               if !strings.HasSuffix(name, "-used-percent") {
+                       continue
+               }
+
+               percent, err := strconv.ParseFloat(value, 64)
+               if err == nil {
+                       used[name] = percent
+               }
+       }
+
+       return used
+}
+
+// writeProbeReport writes the result of a probe run.
+func writeProbeReport(out io.Writer, appended int, stop string, records []usageRecord, sizes []int) error {
+       var input, cached, output, failed int
+       for _, record := range records {
+               input += record.InputTokens
+               cached += record.CachedTokens
+               output += record.OutputTokens
+               if record.Error != "" {
+                       failed++
+               }
+       }
+
+       var lines []string
+       if stop != "" {
+               lines = append(lines, "stopped early: "+stop)
+       }
+
+       lines = append(lines,
+               fmt.Sprintf("messages: %d", appended),
+               fmt.Sprintf("calls: %d (%d failed), %.2f per message", len(records), failed, ratio(len(records), appended)),
+               fmt.Sprintf("model lines: %d, retries: %d", len(sizes), len(records)-failed-len(sizes)),
+               fmt.Sprintf("tokens: %d input, %d cached (%.1f%%), %d output", input, cached, 100*ratio(cached, input), output),
+       )
+
+       if len(sizes) > 0 {
+               lines = append(lines, sizeText(sizes))
+       }
+
+       if len(records) > 0 {
+               lines = append(lines,
+                       "quota at the first call: "+quotaText(records[0]),
+                       "quota at the last call: "+quotaText(records[len(records)-1]),
+               )
+       }
+
+       _, err := io.WriteString(out, strings.Join(lines, "\n")+"\n")
+
+       return err
+}
+
+// sizeText describes the sizes of the model lines.
+func sizeText(sizes []int) string {
+       sorted := slices.Sorted(slices.Values(sizes))
+       total, over := 0, 0
+       for _, size := range sorted {
+               total += size
+               if size > nodeBytes {
+                       over++
+               }
+       }
+
+       return fmt.Sprintf("line bytes: min %d, median %d, mean %.0f, max %d, %d over %d", sorted[0], sorted[len(sorted)/2], ratio(total, len(sorted)), sorted[len(sorted)-1], over, nodeBytes)
+}
+
+// quotaText returns the quota headers of record, sorted by name.
+func quotaText(record usageRecord) string {
+       names := slices.Sorted(maps.Keys(record.Quota))
+       parts := make([]string, len(names))
+       for n, name := range names {
+               parts[n] = strings.TrimPrefix(name, "x-codex-") + "=" + record.Quota[name]
+       }
+
+       return strings.Join(parts, " ")
+}
+
+// ratio returns a / b, or 0 when b is 0.
+func ratio(a, b int) float64 {
+       if b == 0 {
+               return 0
+       }
+
+       return float64(a) / float64(b)
+}

diff --git a/probe_test.go b/probe_test.go
new file mode 100644 (file)
index 0000000..c7436dc
--- /dev/null
+++ b/probe_test.go
@@ -0,0 +1,286 @@
+package main
+
+import (
+       "encoding/json"
+       "fmt"
+       "math/rand/v2"
+       "net/http"
+       "os"
+       "path/filepath"
+       "strconv"
+       "strings"
+       "testing"
+
+       "github.com/stretchr/testify/require"
+)
+
+// probeMessages is the length of the generated log for the live probe.
+const probeMessages = 1000
+
+// TestProbeLogHasTheSyntheticMix checks that the generated log has readable
+// ASCII text with the mix of kinds and sizes of the synthetic log. When
+// ONECHAT_PROBE_LOG names a file, the test also writes the log there, one
+// message {kind, text} per line, for "onechat probe".
+func TestProbeLogHasTheSyntheticMix(t *testing.T) {
+       messages := probeLog(probeMessages)
+       require.Len(t, messages, probeMessages)
+
+       counts := make(map[string]int)
+       long := 0
+       for _, message := range messages {
+               counts[message.Kind]++
+               require.True(t, kinds[message.Kind], message.Kind)
+               require.NotEmpty(t, message.Text)
+               for _, char := range message.Text {
+                       require.True(t, char == '\n' || (char >= ' ' && char <= '~'), "character %q", char)
+               }
+
+               if len(message.Text) >= 30000 {
+                       long++
+               }
+
+               if message.Kind == "work" {
+                       require.True(t, strings.HasPrefix(message.Text, "["), message.Text)
+               }
+       }
+
+       require.Greater(t, counts["user"], 20)
+       require.Greater(t, counts["tool"], 300)
+       require.Greater(t, counts["echo"], 300)
+       require.Greater(t, long, 2)
+       require.Equal(t, messages, probeLog(probeMessages))
+
+       path := os.Getenv("ONECHAT_PROBE_LOG")
+       if path == "" {
+               return
+       }
+
+       var data strings.Builder
+       for _, message := range messages {
+               line, err := json.Marshal(message)
+               require.NoError(t, err)
+
+               data.Write(line)
+               data.WriteByte('\n')
+       }
+
+       require.NoError(t, os.WriteFile(path, []byte(data.String()), 0o600))
+}
+
+func TestProbeStopRules(t *testing.T) {
+       quota := func(primary, secondary string) usageRecord {
+               return usageRecord{
+                       Quota: map[string]string{
+                               "x-codex-primary-used-percent":   primary,
+                               "x-codex-secondary-used-percent": secondary,
+                               "x-codex-plan-type":              "plus",
+                       },
+               }
+       }
+
+       testCases := []struct {
+               name    string
+               records []usageRecord
+               want    string
+       }{
+               {
+                       name:    "no calls",
+                       records: nil,
+                       want:    "",
+               },
+               {
+                       name:    "growth within the limit",
+                       records: []usageRecord{quota("10", "40"), quota("25", "41")},
+                       want:    "",
+               },
+               {
+                       name:    "growth over the limit",
+                       records: []usageRecord{quota("10", "40"), quota("12", "55.5")},
+                       want:    "x-codex-secondary-used-percent grew from 40 to 55.5",
+               },
+               {
+                       name: "failed call",
+                       records: []usageRecord{quota("10", "40"), {
+                               Status: 400,
+                               Error:  "model call: HTTP 400",
+                       }},
+                       want: "call failed: model call: HTTP 400",
+               },
+       }
+
+       for _, tc := range testCases {
+               t.Run(tc.name, func(t *testing.T) {
+                       require.Equal(t, tc.want, probeStop(tc.records))
+               })
+       }
+}
+
+func TestProbeRunStopsWhenTheQuotaGrows(t *testing.T) {
+       server := newFakeResponses(t)
+       server.reply = func(w http.ResponseWriter, call fakeCall) {
+               w.Header().Set("X-Codex-Primary-Used-Percent", strconv.Itoa(10+call.number))
+               writeEvents(w, completedEvent([]any{messageItem(strings.Repeat("s", 400))}, 1000, 800, 50))
+       }
+
+       root := t.TempDir()
+       usagePath := filepath.Join(root, "usage.jsonl")
+       client := newClient(server.URL, apiKey(testKey), "onechat-"+probeName, usagePath)
+       memory, err := openMemory(t.Context(), root, newTestClock().Now, newCompactor(client, probeName, defaultConfig().Compactor))
+       require.NoError(t, err)
+
+       appended, stop := runProbe(t.Context(), memory, probeLog(probeMessages), usagePath)
+       sizes, err := modelLines(memory)
+       require.NoError(t, err)
+       require.NoError(t, memory.Close())
+
+       require.Contains(t, stop, "x-codex-primary-used-percent grew from 10 to")
+       require.Less(t, appended, probeMessages)
+       require.NotEmpty(t, sizes)
+
+       records, err := readUsageFile(usagePath)
+       require.NoError(t, err)
+       require.Greater(t, len(records), int(probeQuotaLimit))
+
+       var report strings.Builder
+       require.NoError(t, writeProbeReport(&report, appended, stop, records, sizes))
+       require.Contains(t, report.String(), "stopped early: ")
+       require.Contains(t, report.String(), "cached (80.0%)")
+       require.Contains(t, report.String(), "line bytes: min 400, median 400, mean 400, max 400, 0 over 512")
+       require.Contains(t, report.String(), "quota at the first call: primary-used-percent=10")
+}
+
+// probeLog returns count messages of made-up work on a small bakery order
+// system, with the mix of kinds and sizes of syntheticMessage. The same count
+// always gives the same log.
+func probeLog(count int) []probeEntry {
+       g := probeWriter{
+               random: rand.New(rand.NewPCG(7, 11)),
+       }
+
+       messages := make([]probeEntry, count)
+       for id := range messages {
+               kind, text := g.message()
+               messages[id] = probeEntry{
+                       Kind: kind,
+                       Text: text,
+               }
+       }
+
+       return messages
+}
+
+// probeWriter writes readable made-up messages.
+type probeWriter struct {
+       random *rand.Rand
+}
+
+func (g *probeWriter) message() (string, string) {
+       roll := g.random.IntN(100)
+       switch {
+       case roll < 5:
+               return "user", g.fill(g.userLine, 10+g.random.IntN(200))
+       case roll < 10:
+               return "reply", g.fill(g.replyLine, 100+g.random.IntN(1500))
+       case roll < 12:
+               return "note", g.fill(g.noteLine, 50+g.random.IntN(600))
+       case roll < 13:
+               return "work", "[" + g.pick(people) + "] report: " + g.fill(g.replyLine, 300+g.random.IntN(3000))
+       case roll < 56:
+               return "tool", g.toolCall(60 + g.random.IntN(400))
+       case roll < 57:
+               return "echo", g.fill(g.outputLine, 30000+g.random.IntN(30000))
+       default:
+               return "echo", g.fill(g.outputLine, 20+g.random.IntN(4000))
+       }
+}
+
+// fill joins lines of write until the text has about size bytes.
+func (g *probeWriter) fill(write func() string, size int) string {
+       var text strings.Builder
+       for text.Len() < size {
+               if text.Len() > 0 {
+                       text.WriteByte(' ')
+               }
+
+               text.WriteString(write())
+       }
+
+       return text.String()
+}
+
+func (g *probeWriter) userLine() string {
+       return g.pick([]string{
+               fmt.Sprintf("Please check why the %s %s.", g.pick(things), g.pick(problems)),
+               fmt.Sprintf("Move the %s to %s before %s.", g.pick(things), g.pick(places), g.pick(days)),
+               fmt.Sprintf("Thanks, that works. Next, %s.", g.pick(tasks)),
+               fmt.Sprintf("No, keep the old %s. %s asked for it.", g.pick(things), g.pick(people)),
+               fmt.Sprintf("How many %s orders came in on %s?", g.pick(breads), g.pick(days)),
+       })
+}
+
+func (g *probeWriter) replyLine() string {
+       return g.pick([]string{
+               fmt.Sprintf("I looked at %s. The %s %s because %s.", g.pick(files), g.pick(things), g.pick(problems), g.pick(causes)),
+               fmt.Sprintf("I changed %s, and the tests pass now.", g.pick(changes)),
+               fmt.Sprintf("There were %d %s orders on %s, %d of them late.", 10+g.random.IntN(90), g.pick(breads), g.pick(days), g.random.IntN(10)),
+               fmt.Sprintf("Open question: should %s get %s?", g.pick(people), g.pick(tasks)),
+       })
+}
+
+func (g *probeWriter) noteLine() string {
+       return g.pick([]string{
+               fmt.Sprintf("%s prefers %s.", g.pick(people), g.pick(preferences)),
+               fmt.Sprintf("The bakery opens at %d and closes at %d on %s.", 5+g.random.IntN(3), 17+g.random.IntN(4), g.pick(days)),
+       })
+}
+
+func (g *probeWriter) outputLine() string {
+       return g.pick([]string{
+               fmt.Sprintf("%02d:%02d order %d for %d %s, packed by %s.", 6+g.random.IntN(12), g.random.IntN(60), 1000+g.random.IntN(9000), 1+g.random.IntN(24), g.pick(breads), g.pick(people)),
+               fmt.Sprintf("%s:%d: %s %s.", g.pick(files), 1+g.random.IntN(400), g.pick(things), g.pick(problems)),
+               fmt.Sprintf("ok   bakery/%s %d.%03ds", g.pick(modules), g.random.IntN(3), g.random.IntN(1000)),
+       })
+}
+
+// toolCall returns a tool name and its JSON input of about size bytes.
+func (g *probeWriter) toolCall(size int) string {
+       name := g.pick([]string{"shell", "read", "write", "edit"})
+       var input map[string]string
+       switch name {
+       case "shell":
+               input = map[string]string{"command": "grep -n '" + g.pick(things) + "' " + g.pick(files)}
+       case "read":
+               input = map[string]string{"path": g.pick(files)}
+       default:
+               input = map[string]string{
+                       "path": g.pick(files),
+                       "text": g.fill(g.replyLine, max(0, size-80)),
+               }
+       }
+
+       data, err := json.Marshal(input)
+       if err != nil {
+               panic(err)
+       }
+
+       return name + " " + string(data)
+}
+
+func (g *probeWriter) pick(words []string) string {
+       return words[g.random.IntN(len(words))]
+}
+
+var (
+       people      = []string{"Mara", "Joel", "Ines", "Tomas", "Priya", "Lena"}
+       breads      = []string{"rye", "sourdough", "baguette", "brioche", "spelt", "seed loaf"}
+       days        = []string{"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}
+       things      = []string{"order form", "price list", "delivery route", "stock count", "invoice export", "oven schedule"}
+       problems    = []string{"shows the wrong total", "skips the last row", "is slow at noon", "loses the customer note", "rounds the tax down"}
+       places      = []string{"the front page", "the weekly report", "the shared folder", "the admin menu"}
+       tasks       = []string{"add a field for allergies", "send the invoices on Friday", "split the route in two", "print labels for the shelf"}
+       causes      = []string{"the date has no time zone", "the cache keeps old prices", "the loop stops one row early", "the form trims the note"}
+       changes     = []string{"the total to use cents", "the route to sort by street", "the export to add the tax line", "the form to keep the note"}
+       preferences = []string{"short answers", "a call before a change to prices", "invoices as PDF", "reports in the morning"}
+       files       = []string{"orders/form.go", "prices/list.go", "routes/plan.go", "stock/count.go", "export/invoice.go", "ovens/schedule.go"}
+       modules     = []string{"orders", "prices", "routes", "stock", "export", "ovens"}
+)