diff --git a/REBUILD.md b/REBUILD.md
index 4c135e4..48eb408 100644
--- a/REBUILD.md
+++ b/REBUILD.md
@@ -62,7 +62,12 @@ the cap is shared by the node's processes).
 
 Also built (2026-10-09): the live tail (new articles planned every 2
 minutes from one LIST ACTIVE per name prefix, at priority −1: leased and
-fetched before history); the catalog API, Newznab (`/api`) and the web
+fetched before history; since 2026-10-27 a round grows the group's open
+tail range, a planned one at the tail's priority nothing spooled or
+took, up to RANGE_ARTICLES before it adds rows, as a tail nothing leased
+had become a sliver a group a round, 127k rows of a median 14k articles;
+`ranges:merge-tail` packs what such rounds left); the catalog API,
+Newznab (`/api`) and the web
 interface, from voyager 1 (the current build), with categories from the
 name; voyager 1's 29 learned garbage signatures (`rules:signatures`,
 `database/data/voyager1_signatures.tsv`).
diff --git a/app/services/planner.ts b/app/services/planner.ts
index 71012b8..eb4d4d4 100644
--- a/app/services/planner.ts
+++ b/app/services/planner.ts
@@ -75,32 +75,99 @@ class Planner {
    * numbers come from LIST ACTIVE, one command per name prefix (GROUP per
    * group took minutes for 1000 groups).
    */
-  async planTail(now = new Date()): Promise<{ groups: number; ranges: number }> {
+  async planTail(now = new Date()): Promise<TailPlanned> {
     const groups = await db.from('groups').where('active', true).where('tail', true).whereNotNull('planned_at').select('id', 'name', 'planned_at')
-    if (groups.length === 0) return { groups: 0, ranges: 0 }
-    const { rows: ends } = await db.rawQuery(`SELECT DISTINCT ON (group_id) group_id, end_id FROM ranges ORDER BY group_id, start_id DESC`)
-    const plannedTo = new Map<number, number>(ends.map((r: any) => [Number(r.group_id), Number(r.end_id)]))
+    if (groups.length === 0) return { groups: 0, ranges: 0, extended: 0 }
+    const { rows: ends } = await db.rawQuery(
+      `SELECT DISTINCT ON (group_id) group_id, id, start_id, end_id,
+              (status = 'planned' AND priority = ? AND NOT capture AND spooled_chunks = 0 AND attempts = 0 AND node_id IS NULL) AS open
+       FROM ranges ORDER BY group_id, start_id DESC`,
+      [coordinatorConfig.tail.priority]
+    )
+    const last = new Map<number, { id: number; start: number; end: number; open: boolean }>(
+      ends.map((r: any) => [Number(r.group_id), { id: Number(r.id), start: Number(r.start_id), end: Number(r.end_id), open: r.open === true }])
+    )
     const highs = new Map<string, number>()
     await NntpPool.use(async (client) => {
       for (const pattern of new Set(groups.map((g) => wildmatOf(g.name)))) {
         for (const g of await client.listActive(pattern)) highs.set(g.name, g.high)
       }
     })
-    const rows = tailRanges(
-      groups.map((g) => ({ id: Number(g.id), plannedTo: plannedTo.get(Number(g.id)) ?? null, plannedAt: new Date(g.planned_at), high: highs.get(g.name) ?? null })),
+    const plan = tailRanges(
+      groups.map((g) => {
+        const l = last.get(Number(g.id))
+        return { id: Number(g.id), plannedTo: l?.end ?? null, plannedAt: new Date(g.planned_at), high: highs.get(g.name) ?? null, open: l?.open ? { id: l.id, start: l.start } : null }
+      }),
       now,
       { rangeArticles: coordinatorConfig.rangeArticles, ...coordinatorConfig.tail }
     )
-    if (rows.length === 0) return { groups: 0, ranges: 0 }
-    await db.transaction(async (trx) => {
-      await trx.table('ranges').multiInsert(rows)
-      for (const id of new Set(rows.map((r) => r.group_id))) {
-        const high = Math.max(...rows.filter((r) => r.group_id === id).map((r) => r.end_id))
-        await trx.from('groups').where('id', id).update({ high, planned_at: now })
-      }
-    })
-    return { groups: new Set(rows.map((r) => r.group_id)).size, ranges: rows.length }
+    return this.applyTail(plan, now)
   }
+
+  /** The tail's plan written: the open ranges extended (one taken meanwhile gets the slice as a row instead), the rows added. */
+  async applyTail(plan: TailPlan, now = new Date()): Promise<TailPlanned> {
+    const rows = [...plan.rows]
+    let extended = 0
+    if (rows.length === 0 && plan.extended.length === 0) return { groups: 0, ranges: 0, extended: 0 }
+    await db.transaction(async (trx) => {
+      for (const e of plan.extended) {
+        const { rows: done } = await trx.rawQuery(
+          `UPDATE ranges SET end_id = ? WHERE id = ? AND status = 'planned' AND spooled_chunks = 0 AND attempts = 0 AND node_id IS NULL AND end_id = ? RETURNING id`,
+          [e.end_id, e.id, e.from - 1]
+        )
+        if (done.length > 0) extended++
+        else rows.push({ group_id: e.group_id, start_id: e.from, end_id: e.end_id, next_id: e.from, priority: coordinatorConfig.tail.priority })
+      }
+      if (rows.length > 0) await trx.table('ranges').multiInsert(rows)
+      const highs = new Map<number, number>()
+      for (const r of [...rows, ...plan.extended]) highs.set(r.group_id, Math.max(highs.get(r.group_id) ?? 0, r.end_id))
+      for (const [id, high] of highs) await trx.from('groups').where('id', id).update({ high, planned_at: now })
+    })
+    return { groups: new Set([...rows, ...plan.extended].map((r) => r.group_id)).size, ranges: rows.length, extended }
+  }
+
+  /**
+   * Adjacent planned tail ranges of a group and priority, never spooled or taken, merged into ranges of at most
+   * RANGE_ARTICLES (ranges:merge-tail): the tail planned a sliver a group every round while nothing leased the tail
+   * (127k rows of a median 14k articles on 2026-10-27; LOG.md (118)). The first row of a run grows, the others go.
+   */
+  async mergeTail(dryRun = false): Promise<{ candidates: number; merged: number; dropped: number }> {
+    const { rows: candidates } = await db.rawQuery(
+      `SELECT id, group_id, start_id, end_id, priority FROM ranges
+       WHERE status = 'planned' AND priority < 0 AND NOT capture AND spooled_chunks = 0 AND attempts = 0 AND node_id IS NULL
+       ORDER BY group_id, start_id`
+    )
+    const merges = tailMerges(
+      candidates.map((r: any) => ({ id: Number(r.id), group_id: Number(r.group_id), start_id: Number(r.start_id), end_id: Number(r.end_id), priority: Number(r.priority) })),
+      coordinatorConfig.rangeArticles
+    )
+    const dropped = merges.reduce((n, m) => n + m.drop.length, 0)
+    if (dryRun || merges.length === 0) return { candidates: candidates.length, merged: merges.length, dropped }
+    await db.transaction(async (trx) => {
+      // The lease picker reads several tables under this lock; the rows' guards catch a range taken meanwhile.
+      await trx.rawQuery(`SELECT pg_advisory_xact_lock(hashtextextended('group-lease', 0))`)
+      const { rows: gone } = await trx.rawQuery(
+        `DELETE FROM ranges WHERE id = ANY(?::bigint[]) AND status = 'planned' AND spooled_chunks = 0 AND attempts = 0 AND node_id IS NULL RETURNING id`,
+        [merges.flatMap((m) => m.drop)]
+      )
+      if (gone.length !== dropped) throw new Error(`${dropped - gone.length} of the ranges to drop were taken meanwhile; nothing merged`)
+      const { rows: grown } = await trx.rawQuery(
+        `UPDATE ranges r SET end_id = v.end_id FROM (SELECT unnest(?::bigint[]) AS id, unnest(?::bigint[]) AS end_id) v
+         WHERE r.id = v.id AND r.status = 'planned' AND r.spooled_chunks = 0 AND r.attempts = 0 AND r.node_id IS NULL RETURNING r.id`,
+        [merges.map((m) => m.id), merges.map((m) => m.end_id)]
+      )
+      if (grown.length !== merges.length) throw new Error(`${merges.length - grown.length} of the ranges to grow were taken meanwhile; nothing merged`)
+    })
+    return { candidates: candidates.length, merged: merges.length, dropped }
+  }
+}
+
+export interface TailPlanned {
+  groups: number
+  /** Rows added. */
+  ranges: number
+  /** Open ranges grown. */
+  extended: number
 }
 
 /** A LIST ACTIVE pattern for a group: its first two name parts (`alt.binaries.*`), or the name itself. */
@@ -117,29 +184,90 @@ export interface TailGroup {
   plannedAt: Date
   /** The server's newest article (null: not listed). */
   high: number | null
+  /**
+   * Its last range when the tail may grow it instead of adding a row: a planned range at the tail's priority that
+   * nothing spooled, took or tried (its start: the cut at rangeArticles counts from there).
+   */
+  open?: { id: number; start: number } | null
+}
+
+export interface TailRow {
+  group_id: number
+  start_id: number
+  end_id: number
+  next_id: number
+  priority: number
+}
+
+export interface TailPlan {
+  /** New ranges. */
+  rows: TailRow[]
+  /** Open ranges grown to end_id (from: the first new article, the old end + 1). */
+  extended: { id: number; group_id: number; from: number; end_id: number }[]
 }
 
 /**
- * The tail's new ranges: per group, the articles after its last range, in
- * ranges of at most `rangeArticles`, once there are `minArticles` of them or
- * the group's last planning is `maxDelayMinutes` ago.
+ * The tail's new ranges: per group, the articles after its last range, once there are `minArticles` of them or
+ * the group's last planning is `maxDelayMinutes` ago. An open last range grows up to `rangeArticles` first, so a
+ * tail nothing leases stays one range a group instead of a sliver a round; the rest is cut at `rangeArticles`.
  */
 export function tailRanges(
   groups: TailGroup[],
   now: Date,
   options: { rangeArticles: number; minArticles: number; maxDelayMinutes: number; priority: number }
-) {
-  const rows: { group_id: number; start_id: number; end_id: number; next_id: number; priority: number }[] = []
+): TailPlan {
+  const rows: TailRow[] = []
+  const extended: TailPlan['extended'] = []
   for (const g of groups) {
     if (g.plannedTo === null || g.high === null || g.high <= g.plannedTo) continue
     const waiting = g.high - g.plannedTo
     const waited = (now.getTime() - g.plannedAt.getTime()) / 60_000
     if (waiting < options.minArticles && waited < options.maxDelayMinutes) continue
-    for (let start = g.plannedTo + 1; start <= g.high; start += options.rangeArticles) {
+    let start = g.plannedTo + 1
+    if (g.open && g.open.start + options.rangeArticles - 1 >= start) {
+      const end = Math.min(g.open.start + options.rangeArticles - 1, g.high)
+      extended.push({ id: g.open.id, group_id: g.id, from: start, end_id: end })
+      start = end + 1
+    }
+    for (; start <= g.high; start += options.rangeArticles) {
       rows.push({ group_id: g.id, start_id: start, end_id: Math.min(start + options.rangeArticles - 1, g.high), next_id: start, priority: options.priority })
     }
   }
-  return rows
+  return { rows, extended }
+}
+
+export interface TailMerge {
+  /** The run's first range, grown to end_id. */
+  id: number
+  end_id: number
+  /** The ranges it absorbed. */
+  drop: number[]
+}
+
+/**
+ * Runs of adjacent ranges of one group and priority (sorted by group and start) packed into ranges of at most
+ * `rangeArticles`: the first range of each packed run grows, the others are dropped. Only runs that merge anything.
+ */
+export function tailMerges(
+  ranges: { id: number; group_id: number; start_id: number; end_id: number; priority: number }[],
+  rangeArticles: number
+): TailMerge[] {
+  const merges: TailMerge[] = []
+  let cur: (TailMerge & { group_id: number; start_id: number; priority: number }) | null = null
+  const flush = () => {
+    if (cur && cur.drop.length > 0) merges.push({ id: cur.id, end_id: cur.end_id, drop: cur.drop })
+  }
+  for (const r of ranges) {
+    if (cur && r.group_id === cur.group_id && r.priority === cur.priority && r.start_id === cur.end_id + 1 && r.end_id - cur.start_id + 1 <= rangeArticles) {
+      cur.end_id = r.end_id
+      cur.drop.push(r.id)
+      continue
+    }
+    flush()
+    cur = { id: r.id, group_id: r.group_id, start_id: r.start_id, end_id: r.end_id, priority: r.priority, drop: [] }
+  }
+  flush()
+  return merges
 }
 
 export default new Planner()
diff --git a/commands/coordinator_run.ts b/commands/coordinator_run.ts
index cce4e78..4a4eea9 100644
--- a/commands/coordinator_run.ts
+++ b/commands/coordinator_run.ts
@@ -117,8 +117,11 @@ export default class CoordinatorRun extends BaseCommand {
         }
         if (main && Date.now() - tailedAt >= coordinatorConfig.tail.everySeconds * 1000) {
           tailedAt = Date.now()
-          const { groups, ranges } = await Planner.planTail()
-          if (ranges > 0) this.logger.info(`Tail: ${ranges} ranges for ${groups} groups.`)
+          const { groups, ranges, extended } = await Planner.planTail()
+          if (ranges + extended > 0)
+            this.logger.info(
+              `Tail: ${ranges} ranges added, ${extended} grown, for ${groups} groups.`
+            )
         }
       } catch (error: any) {
         this.logger.error(`Coordinator round failed: ${error.message}`)
diff --git a/commands/ranges_merge_tail.ts b/commands/ranges_merge_tail.ts
new file mode 100644
index 0000000..de1a4ad
--- /dev/null
+++ b/commands/ranges_merge_tail.ts
@@ -0,0 +1,23 @@
+import { BaseCommand, flags } from '@adonisjs/core/ace'
+import type { CommandOptions } from '@adonisjs/core/types/ace'
+import Planner from '#services/planner'
+
+/**
+ * Merges adjacent planned tail ranges (Planner.mergeTail): the tail planner added a sliver a group every round
+ * while nothing leased the tail; now it grows the group's open range instead, and this packs what is there.
+ */
+export default class RangesMergeTail extends BaseCommand {
+  static commandName = 'ranges:merge-tail'
+  static description = 'Merges adjacent planned tail ranges into ranges of RANGE_ARTICLES'
+  static options: CommandOptions = { startApp: true }
+
+  @flags.boolean({ description: 'Only count what would be merged' })
+  declare dryRun: boolean
+
+  async run() {
+    const { candidates, merged, dropped } = await Planner.mergeTail(this.dryRun)
+    this.logger.info(
+      `${candidates} planned tail ranges: ${dropped} ${this.dryRun ? 'would merge' : 'merged'} into ${merged} grown ranges (${candidates - dropped} left).`
+    )
+  }
+}
diff --git a/commands/ranges_plan.ts b/commands/ranges_plan.ts
index 8534ea9..8e1b6bb 100644
--- a/commands/ranges_plan.ts
+++ b/commands/ranges_plan.ts
@@ -14,8 +14,13 @@ export default class RangesPlan extends BaseCommand {
 
   async run() {
     try {
-      const { groups, ranges } = this.tail ? await Planner.planTail() : await Planner.planAll()
-      this.logger.info(`${ranges} ${this.tail ? 'tail ' : ''}ranges planned over ${groups} groups.`)
+      if (this.tail) {
+        const { groups, ranges, extended } = await Planner.planTail()
+        this.logger.info(`Tail: ${ranges} ranges added, ${extended} grown, over ${groups} groups.`)
+      } else {
+        const { groups, ranges } = await Planner.planAll()
+        this.logger.info(`${ranges} ranges planned over ${groups} groups.`)
+      }
     } finally {
       await NntpPool.close()
     }
diff --git a/tests/functional/planner_tail.spec.ts b/tests/functional/planner_tail.spec.ts
new file mode 100644
index 0000000..65cfa43
--- /dev/null
+++ b/tests/functional/planner_tail.spec.ts
@@ -0,0 +1,142 @@
+import { test } from '@japa/runner'
+import db from '@adonisjs/lucid/services/db'
+import testUtils from '@adonisjs/core/services/test_utils'
+import Planner from '#services/planner'
+import coordinatorConfig from '#config/coordinator'
+
+const TAIL = coordinatorConfig.tail.priority
+
+test.group('Planner / tail ranges', (group) => {
+  group.each.setup(() => testUtils.db().withGlobalTransaction())
+
+  test('applyTail grows an open range, or adds the slice when the range was taken meanwhile', async ({
+    assert,
+  }) => {
+    const [g] = await db
+      .table('groups')
+      .insert({
+        name: 'alt.binaries.tail',
+        priority: 1,
+        tail: true,
+        planned_at: new Date('2026-10-27T08:00:00Z'),
+      })
+      .returning('id')
+    const [open] = await db
+      .table('ranges')
+      .insert({ group_id: g.id, start_id: 1, end_id: 300, next_id: 1, priority: TAIL })
+      .returning('id')
+    const [taken] = await db
+      .table('ranges')
+      .insert({
+        group_id: g.id,
+        start_id: 301,
+        end_id: 400,
+        next_id: 301,
+        priority: TAIL,
+        status: 'leased',
+        node_id: 1,
+      })
+      .returning('id')
+    const now = new Date('2026-10-27T09:00:00Z')
+    const planned = await Planner.applyTail(
+      {
+        rows: [
+          { group_id: Number(g.id), start_id: 2001, end_id: 2500, next_id: 2001, priority: TAIL },
+        ],
+        extended: [
+          { id: Number(open.id), group_id: Number(g.id), from: 301, end_id: 2000 },
+          { id: Number(taken.id), group_id: Number(g.id), from: 401, end_id: 600 },
+        ],
+      },
+      now
+    )
+    assert.deepEqual(planned, { groups: 1, ranges: 2, extended: 1 })
+    const ranges = await db
+      .from('ranges')
+      .where('group_id', g.id)
+      .orderBy('start_id')
+      .select('start_id', 'end_id', 'status', 'priority')
+    assert.deepEqual(
+      ranges.map((r) => [Number(r.start_id), Number(r.end_id), r.status, Number(r.priority)]),
+      [
+        [1, 2000, 'planned', TAIL],
+        [301, 400, 'leased', TAIL],
+        [401, 600, 'planned', TAIL],
+        [2001, 2500, 'planned', TAIL],
+      ]
+    )
+    const updated = await db.from('groups').where('id', g.id).firstOrFail()
+    assert.equal(Number(updated.high), 2500)
+    assert.equal(new Date(updated.planned_at).toISOString(), now.toISOString())
+  })
+
+  test('mergeTail packs adjacent planned tail ranges and leaves taken, spooled, capture and history ranges alone', async ({
+    assert,
+  }) => {
+    const saved = coordinatorConfig.rangeArticles
+    coordinatorConfig.rangeArticles = 1000
+    try {
+      const [g] = await db
+        .table('groups')
+        .insert({ name: 'alt.binaries.tail', priority: 1, tail: true })
+        .returning('id')
+      const gid = Number(g.id)
+      const range = (start_id: number, end_id: number, extra: Record<string, unknown> = {}) => ({
+        group_id: gid,
+        start_id,
+        end_id,
+        next_id: start_id,
+        priority: TAIL,
+        ...extra,
+      })
+      await db.table('ranges').multiInsert([
+        // History, then a run of five slivers (the fifth is spooled: a break), two more, a capture range, the tail's rest.
+        range(1, 1000, { priority: 500, status: 'done' }),
+        range(1001, 1100),
+        range(1101, 1200),
+        range(1201, 1300),
+        range(1301, 1400),
+        range(1401, 1500, { spooled_chunks: 1 }),
+        range(1501, 1600),
+        range(1601, 1700),
+        range(1701, 1800, { capture: true }),
+        range(1801, 2600),
+        range(2601, 2700),
+        range(2701, 2800, { status: 'leased', node_id: 1 }),
+      ])
+      assert.deepEqual(await Planner.mergeTail(true), { candidates: 8, merged: 3, dropped: 5 })
+      assert.equal(
+        (await db.from('ranges').where('group_id', gid).count('* as n').first())!.n,
+        '12'
+      )
+      assert.deepEqual(await Planner.mergeTail(), { candidates: 8, merged: 3, dropped: 5 })
+      const ranges = await db
+        .from('ranges')
+        .where('group_id', gid)
+        .orderBy('start_id')
+        .select('start_id', 'end_id', 'next_id', 'status', 'priority', 'capture')
+      assert.deepEqual(
+        ranges.map((r) => [
+          Number(r.start_id),
+          Number(r.end_id),
+          Number(r.next_id),
+          r.status,
+          Number(r.priority),
+          r.capture,
+        ]),
+        [
+          [1, 1000, 1, 'done', 500, false],
+          [1001, 1400, 1001, 'planned', TAIL, false],
+          [1401, 1500, 1401, 'planned', TAIL, false],
+          [1501, 1700, 1501, 'planned', TAIL, false],
+          [1701, 1800, 1701, 'planned', TAIL, true],
+          [1801, 2700, 1801, 'planned', TAIL, false],
+          [2701, 2800, 2701, 'leased', TAIL, false],
+        ]
+      )
+      assert.deepEqual(await Planner.mergeTail(), { candidates: 3, merged: 0, dropped: 0 })
+    } finally {
+      coordinatorConfig.rangeArticles = saved
+    }
+  })
+})
diff --git a/tests/unit/coordinator/tail.spec.ts b/tests/unit/coordinator/tail.spec.ts
index f2e0b8c..a654648 100644
--- a/tests/unit/coordinator/tail.spec.ts
+++ b/tests/unit/coordinator/tail.spec.ts
@@ -1,5 +1,5 @@
 import { test } from '@japa/runner'
-import { tailRanges, wildmatOf } from '#services/planner'
+import { tailMerges, tailRanges, wildmatOf } from '#services/planner'
 
 const options = { rangeArticles: 1000, minArticles: 100, maxDelayMinutes: 15, priority: -1 }
 const now = new Date('2026-10-09T10:00:00Z')
@@ -7,7 +7,7 @@ const minutesAgo = (m: number) => new Date(now.getTime() - m * 60_000)
 
 test.group('coordinator / live tail', () => {
   test('a chunk of new articles, or a long enough wait, makes tail ranges', ({ assert }) => {
-    const rows = tailRanges(
+    const { rows, extended } = tailRanges(
       [
         // Enough new articles: planned at once, cut at rangeArticles.
         { id: 1, plannedTo: 5000, plannedAt: minutesAgo(2), high: 7500 },
@@ -32,6 +32,94 @@ test.group('coordinator / live tail', () => {
         [3, 101, 103, 101, -1],
       ]
     )
+    assert.deepEqual(extended, [])
+  })
+
+  test('an open last range grows up to rangeArticles before rows are added', ({ assert }) => {
+    const { rows, extended } = tailRanges(
+      [
+        // Room in the open range for everything new.
+        {
+          id: 1,
+          plannedTo: 5300,
+          plannedAt: minutesAgo(20),
+          high: 5350,
+          open: { id: 11, start: 5001 },
+        },
+        // The open range fills up, the rest is cut as rows.
+        {
+          id: 2,
+          plannedTo: 5300,
+          plannedAt: minutesAgo(2),
+          high: 7500,
+          open: { id: 12, start: 5001 },
+        },
+        // An open range already full: rows only.
+        {
+          id: 3,
+          plannedTo: 6000,
+          plannedAt: minutesAgo(2),
+          high: 6500,
+          open: { id: 13, start: 5001 },
+        },
+        // Not open (taken, spooled, another priority): rows.
+        { id: 4, plannedTo: 5300, plannedAt: minutesAgo(20), high: 5350, open: null },
+      ],
+      now,
+      options
+    )
+    assert.deepEqual(
+      extended.map((e) => [e.id, e.group_id, e.from, e.end_id]),
+      [
+        [11, 1, 5301, 5350],
+        [12, 2, 5301, 6000],
+      ]
+    )
+    assert.deepEqual(
+      rows.map((r) => [r.group_id, r.start_id, r.end_id]),
+      [
+        [2, 6001, 7000],
+        [2, 7001, 7500],
+        [3, 6001, 6500],
+        [4, 5301, 5350],
+      ]
+    )
+  })
+
+  test('adjacent ranges of a group and priority pack into rangeArticles; gaps and other priorities break a run', ({
+    assert,
+  }) => {
+    const r = (id: number, group_id: number, start_id: number, end_id: number, priority = -3) => ({
+      id,
+      group_id,
+      start_id,
+      end_id,
+      priority,
+    })
+    const merges = tailMerges(
+      [
+        // 1–300 + 301–600 + 601–900 fill 1000 with 901–1000; 1001–1100 starts the next run alone.
+        r(1, 1, 1, 300),
+        r(2, 1, 301, 600),
+        r(3, 1, 601, 900),
+        r(4, 1, 901, 1000),
+        r(5, 1, 1001, 1100),
+        // A gap, then two adjacent at another priority.
+        r(6, 1, 1200, 1250),
+        r(7, 1, 1251, 1300, -1),
+        r(8, 1, 1301, 1400, -1),
+        // Another group; one that would overflow stays alone.
+        r(9, 2, 1, 900),
+        r(10, 2, 901, 1100),
+        r(11, 2, 1101, 1150),
+      ],
+      1000
+    )
+    assert.deepEqual(merges, [
+      { id: 1, end_id: 1000, drop: [2, 3, 4] },
+      { id: 7, end_id: 1400, drop: [8] },
+      { id: 10, end_id: 1150, drop: [11] },
+    ])
   })
 
   test('LIST ACTIVE patterns by the first two name parts', ({ assert }) => {