feat(brain): surface an aging review queue in brain_context (#82)

brain_pending existed the whole time four real items sat unreviewed from
2026-04-23 to 2026-07-15. The tool was never the gap — nothing ever
prompted anyone to call it. The system should be what remembers the queue
exists.

Option 2 from the issue: ride along with brain_context, which sessions
already call, so noticing an aging note costs nobody a decision to go
looking. No scheduled job, no ntfy wiring, nothing new to keep running.

Threshold-gated at 14 days, and silent below it — a notice on every
context call is one people learn to skip, which reproduces the original
failure with extra steps. It reports the whole queue once it speaks: the
threshold decides whether to talk, not what to count.

It never promotes, rejects or reorders. Age is a reason to ask a human,
not a verdict; an old note may be exactly right to promote once someone
looks. A test asserts the queue is untouched and that the payload carries
a hint rather than an action.

An unreadable raw/ dir degrades to silence — brain_context is a hot path
and must not fail because the review queue is broken.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BeAp5LTscnz2W7Ubt4eJ6m

ingestion/internal/mcp/pending_nudge.go

@@ -0,0 +1,76 @@
+package mcp
+
+import (
+	"time"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
+)
+
+// pendingNudgeThreshold is how old a raw/ note has to be before brain_context
+// mentions the queue. Two weeks: long enough that a note written this sprint
+// does not nag, short enough that four items cannot sit unnoticed for three
+// months again (#82).
+const pendingNudgeThreshold = 14 * 24 * time.Hour
+
+// PendingNudge is the in-session reminder that the promote/reject queue has
+// items waiting. It is advisory: a count, an age, and how to look.
+type PendingNudge struct {
+	Pending    int    `json:"pending"`     // everything in the queue
+	Aging      int    `json:"aging"`       // those past the threshold
+	Oldest     string `json:"oldest"`      // filename of the oldest pending note
+	OldestDays int    `json:"oldest_days"` // its age, in whole days
+	Hint       string `json:"hint"`
+}
+
+// pendingNudge summarises the raw/ review queue, or returns nil when there is
+// nothing worth saying.
+//
+// The trigger is the missing half of the queue (#82): brain_pending has always
+// existed, and four real items still sat unreviewed from 2026-04-23 to
+// 2026-07-15 because nothing ever prompted anyone to call it. The system
+// should be what remembers the queue exists.
+//
+// Threshold-gated on purpose. A notice on every context call is one people
+// learn to skip, which reproduces the original failure with extra steps.
+//
+// It never promotes, rejects, or reorders anything. Age is a reason to ask a
+// human, not a verdict — an old note may be exactly right to promote once
+// someone finally looks at it.
+func pendingNudge(brainDir string, now time.Time, threshold time.Duration) *PendingNudge {
+	pending, err := api.ListPending(brainDir)
+	if err != nil || len(pending) == 0 {
+		// brain_context is a hot path; a broken queue degrades to silence
+		// rather than failing the call that asked for project context.
+		return nil
+	}
+
+	var aging int
+	var oldestName string
+	var oldestAge time.Duration
+
+	for _, p := range pending {
+		created, perr := time.Parse(time.RFC3339, p.CreatedAt)
+		if perr != nil {
+			continue // an unparseable timestamp is not evidence of age
+		}
+		age := now.Sub(created)
+		if age >= threshold {
+			aging++
+		}
+		if age > oldestAge {
+			oldestAge, oldestName = age, p.Filename
+		}
+	}
+
+	if aging == 0 {
+		return nil
+	}
+
+	return &PendingNudge{
+		Pending:    len(pending),
+		Aging:      aging,
+		Oldest:     oldestName,
+		OldestDays: int(oldestAge.Hours() / 24),
+		Hint:       "call brain_pending to review; nothing is promoted or rejected automatically",
+	}
+}

ingestion/internal/mcp/pending_nudge_test.go

@@ -0,0 +1,115 @@
+package mcp
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// writePending drops a raw/ note whose created_at is age old.
+func writePending(t *testing.T, brainDir, name string, age time.Duration, now time.Time) {
+	t.Helper()
+	raw := filepath.Join(brainDir, "raw")
+	require.NoError(t, os.MkdirAll(raw, 0o755))
+	body := "---\ncreated_at: " + now.Add(-age).UTC().Format(time.RFC3339) + "\n---\n\nnote body\n"
+	require.NoError(t, os.WriteFile(filepath.Join(raw, name), []byte(body), 0o644))
+}
+
+func TestPendingNudge_SilentWhenNothingIsPending(t *testing.T) {
+	// No queue, no nudge. A notice that fires every session is one people
+	// learn to skip, which is how the queue got ignored for three months in
+	// the first place (#82).
+	got := pendingNudge(t.TempDir(), time.Now(), 14*24*time.Hour)
+	assert.Nil(t, got)
+}
+
+func TestPendingNudge_SilentWhileEverythingIsBelowTheThreshold(t *testing.T) {
+	now := time.Now()
+	dir := t.TempDir()
+	writePending(t, dir, "fresh.md", 2*24*time.Hour, now)
+
+	got := pendingNudge(dir, now, 14*24*time.Hour)
+	assert.Nil(t, got, "a two-day-old note is not aging")
+}
+
+func TestPendingNudge_ReportsCountAndOldestAgeOnceSomethingAges(t *testing.T) {
+	now := time.Now()
+	dir := t.TempDir()
+	writePending(t, dir, "old.md", 100*24*time.Hour, now)
+	writePending(t, dir, "older.md", 120*24*time.Hour, now)
+	writePending(t, dir, "fresh.md", 1*24*time.Hour, now)
+
+	got := pendingNudge(dir, now, 14*24*time.Hour)
+	require.NotNil(t, got)
+
+	// All three are pending; the threshold decides whether to speak, not
+	// what to count. Someone opening the queue sees the whole queue.
+	assert.Equal(t, 3, got.Pending)
+	assert.Equal(t, 2, got.Aging)
+	assert.Equal(t, 120, got.OldestDays)
+	assert.Equal(t, "older.md", got.Oldest)
+}
+
+func TestPendingNudge_NeverDecidesAnything(t *testing.T) {
+	// Aging is a trigger to ask a human, never a verdict. The nudge must
+	// carry no action and must leave the queue exactly as it found it.
+	now := time.Now()
+	dir := t.TempDir()
+	writePending(t, dir, "ancient.md", 365*24*time.Hour, now)
+
+	before, err := os.ReadDir(filepath.Join(dir, "raw"))
+	require.NoError(t, err)
+
+	got := pendingNudge(dir, now, 14*24*time.Hour)
+	require.NotNil(t, got)
+
+	after, err := os.ReadDir(filepath.Join(dir, "raw"))
+	require.NoError(t, err)
+	assert.Len(t, after, len(before), "the nudge must not promote or reject anything")
+	assert.Contains(t, got.Hint, "brain_pending", "the nudge should say how to look, not act")
+}
+
+func TestPendingNudge_SurvivesAnUnreadableQueue(t *testing.T) {
+	// brain_context is a hot path; a broken raw/ dir must degrade to silence
+	// rather than failing the whole context call.
+	dir := t.TempDir()
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw"), []byte("not a directory"), 0o644))
+
+	assert.NotPanics(t, func() {
+		assert.Nil(t, pendingNudge(dir, time.Now(), 14*24*time.Hour))
+	})
+}
+
+func TestBrainContext_CarriesTheNudgeWithoutFailingWhenTheQueueIsEmpty(t *testing.T) {
+	// The wiring, not the summary: a nudge that never reaches a caller is the
+	// same as no nudge, and brain_context must still work with no queue.
+	dir := t.TempDir()
+	srv := NewServer(dir, nil, nil, nil)
+
+	raw, err := srv.brainContext(context.Background(),
+		json.RawMessage(`{"project_root":"/home/mathias/dev/AGENTS/hyperguild"}`))
+	require.NoError(t, err)
+
+	var empty map[string]any
+	require.NoError(t, json.Unmarshal(raw, &empty))
+	assert.NotContains(t, empty, "pending_review", "silence when nothing is aging")
+
+	writePending(t, dir, "ancient.md", 200*24*time.Hour, time.Now())
+
+	raw, err = srv.brainContext(context.Background(),
+		json.RawMessage(`{"project_root":"/home/mathias/dev/AGENTS/hyperguild"}`))
+	require.NoError(t, err)
+
+	var withQueue map[string]any
+	require.NoError(t, json.Unmarshal(raw, &withQueue))
+	nudge, ok := withQueue["pending_review"].(map[string]any)
+	require.True(t, ok, "the nudge must reach the caller: %v", withQueue)
+	assert.Equal(t, float64(1), nudge["aging"])
+	assert.Equal(t, "ancient.md", nudge["oldest"])
+}

ingestion/internal/mcp/tools_context.go

@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/search"
 )
@@ -155,7 +156,14 @@ func (s *Server) brainContext(ctx context.Context, args json.RawMessage) (json.R
 		entries = entries[:limit]
 	}
 
-	return json.Marshal(map[string]any{"entries": entries})
+	out := map[string]any{"entries": entries}
+	// The queue nudge rides along with a call the session already makes, so
+	// noticing an aging note costs nobody a decision to go looking (#82).
+	// Advisory only, and absent entirely when there is nothing to say.
+	if n := pendingNudge(s.brainDir, time.Now(), pendingNudgeThreshold); n != nil {
+		out["pending_review"] = n
+	}
+	return json.Marshal(out)
 }
 
 // truncateExcerpt clamps an already-stripped excerpt to maxLen characters