diff --git a/config/scripts/mobile-file-ranking-benchmark.mjs b/config/scripts/mobile-file-ranking-benchmark.mjs
index 68ac5b9d977..27bf99f8ecd 100644
--- a/config/scripts/mobile-file-ranking-benchmark.mjs
+++ b/config/scripts/mobile-file-ranking-benchmark.mjs
@@ -1,53 +1,141 @@
 import assert from 'node:assert/strict'
 import { execFileSync } from 'node:child_process'
 import { readFileSync } from 'node:fs'
-import { stripTypeScriptTypes } from 'node:module'
 import { performance } from 'node:perf_hooks'
+import { transform } from 'esbuild'
+import { buildCounterbalancedSchedule } from './counterbalanced-benchmark-schedule.mjs'
+import { summarizeBenchmarkSamples } from './benchmark-sample-summary.mjs'
 
 const baseline = process.argv[2]
 if (!baseline) {
-  throw new Error('Usage: node config/scripts/mobile-file-ranking-benchmark.mjs <baseline-ref>')
+  throw new Error(
+    'Usage: node config/scripts/mobile-file-ranking-benchmark.mjs <baseline-ref|--autocomplete-stdin>'
+  )
 }
+// git show <ref>:mobile/src/session/mobile-native-chat-autocomplete.ts | node config/scripts/mobile-file-ranking-benchmark.mjs --autocomplete-stdin
+const autocompleteSource = baseline === '--autocomplete-stdin' ? readFileSync(0, 'utf8') : null
 async function load(source) {
-  const js = stripTypeScriptTypes(source, { mode: 'transform' })
-  return await import(`data:text/javascript;base64,${Buffer.from(js).toString('base64')}`)
-}
-function measure(fn, paths, query) {
-  for (let warmup = 0; warmup < 10; warmup++) {
-    fn(paths, query, 16)
-  }
-  const samples = []
-  for (let i = 0; i < 9; i++) {
-    const start = performance.now()
-    fn(paths, query, 16)
-    samples.push(performance.now() - start)
-  }
-  return samples.sort((a, b) => a - b)[4]
+  const { code } = await transform(source, { loader: 'ts', format: 'esm' })
+  return await import(`data:text/javascript;base64,${Buffer.from(code).toString('base64')}`)
 }
 const results = []
+let differentialCases = 0
 for (const [file, name] of [
   ['src/main/runtime/runtime-mobile-file-path-search.ts', 'rankRuntimeMobileFilePaths'],
-  ['mobile/src/session/mobile-native-chat-autocomplete.ts', 'rankSuggestions']
+  ['mobile/src/session/mobile-native-chat-autocomplete.ts', 'rankSuggestions'],
+  ['mobile/src/session/mobile-native-chat-autocomplete.ts', 'rankSlashCommandSuggestions']
 ]) {
+  if (autocompleteSource !== null && name === 'rankRuntimeMobileFilePaths') {
+    continue
+  }
   const before = (
-    await load(execFileSync('git', ['show', `${baseline}:${file}`], { encoding: 'utf8' }))
+    await load(
+      autocompleteSource ??
+        execFileSync('git', ['show', `${baseline}:${file}`], { encoding: 'utf8' })
+    )
   )[name]
   const after = (await load(readFileSync(file, 'utf8')))[name]
-  for (const count of [100, 100000]) {
-    const paths = Array.from(
-      { length: count },
-      (_, i) => `src/components/workspace/group-${i % 100}/file-${i}.tsx`
+  const slash = name === 'rankSlashCommandSuggestions'
+  const toCandidates = (names) =>
+    slash ? names.map((name, index) => ({ name, description: `Command ${index}` })) : names
+  if (name !== 'rankRuntimeMobileFilePaths') {
+    let seed = 42
+    const random = (max) => {
+      seed = (Math.imul(seed, 1664525) + 1013904223) >>> 0
+      return seed % max
+    }
+    const tokens = ['', 'app', 'src/', 'APP', 'zapp', '🙂', '한', '\ud800', '\u0130', ' ']
+    const limits = [
+      undefined,
+      0,
+      -0,
+      -1,
+      -0.5,
+      -Infinity,
+      Number.NaN,
+      0.5,
+      1.5,
+      2.5,
+      8,
+      16,
+      Infinity
+    ]
+    for (let index = 0; index < 3000; index += 1) {
+      const candidates = toCandidates(
+        Array.from(
+          { length: random(100) },
+          () => tokens[random(tokens.length)] + tokens[random(tokens.length)]
+        )
+      )
+      const query = tokens[random(tokens.length)]
+      const limit = limits[random(limits.length)]
+      assert.deepEqual(after(candidates, query, limit), before(candidates, query, limit))
+      differentialCases += 1
+    }
+  }
+  for (const count of slash ? [16, 100, 1000] : [16, 100, 10_000, 50_000, 100_000]) {
+    const names = Array.from({ length: count }, (_, index) =>
+      slash
+        ? `team-review-${index}`
+        : `src/components/workspace/group-${index % 100}/file-${index}.tsx`
     )
-    for (const query of ['file-9', 'missing', 'workspace']) {
-      assert.deepEqual(after(paths, query, 16), before(paths, query, 16))
+    const limit = slash ? 12 : 16
+    const substringQuery = slash ? 'review' : 'workspace'
+    const workloads = [
+      { name: 'empty-query', names, query: '' },
+      { name: 'substring', names, query: substringQuery },
+      { name: 'no-match', names, query: 'missing' },
+      { name: 'early-prefix', names, query: slash ? 'team' : 'file' },
+      {
+        name: 'late-prefix',
+        names: [...names, ...Array.from({ length: 4 }, (_, index) => `${substringQuery}-${index}`)],
+        query: substringQuery
+      }
+    ]
+    for (const workload of workloads) {
+      const candidates = toCandidates(workload.names)
+      const expected = before(candidates, workload.query, limit)
+      assert.deepEqual(after(candidates, workload.query, limit), expected)
+      const implementations = { before, after }
+      const iterations = Math.max(10, Math.floor(100_000 / count))
+      for (let warmup = 0; warmup < 100; warmup += 1) {
+        before(candidates, workload.query, limit)
+        after(candidates, workload.query, limit)
+      }
+      /** @type {{ before: number[], after: number[] }} */
+      const samples = { before: [], after: [] }
+      for (const pair of buildCounterbalancedSchedule(8, 'before', 'after')) {
+        for (const arm of pair) {
+          let actual
+          const start = performance.now()
+          for (let repeat = 0; repeat < iterations; repeat += 1) {
+            actual = implementations[arm](candidates, workload.query, limit)
+          }
+          samples[arm].push(performance.now() - start)
+          assert.deepEqual(actual, expected)
+        }
+      }
       results.push({
         function: name,
-        paths: count,
-        query,
-        beforeMs: measure(before, paths, query),
-        afterMs: measure(after, paths, query)
+        candidates: candidates.length,
+        workload: workload.name,
+        iterations,
+        meanMicrosecondsPerCall: Object.fromEntries(
+          Object.entries(samples).map(([arm, values]) => [
+            arm,
+            (values.reduce((sum, ms) => sum + ms, 0) * 1000) / values.length / iterations
+          ])
+        ),
+        before: summarizeBenchmarkSamples(samples.before),
+        after: summarizeBenchmarkSamples(samples.after)
       })
     }
   }
 }
-console.log(JSON.stringify({ node: process.version, platform: process.platform, results }, null, 2))
+console.log(
+  JSON.stringify(
+    { node: process.version, platform: process.platform, differentialCases, results },
+    null,
+    2
+  )
+)
diff --git a/mobile/src/session/mobile-native-chat-autocomplete.test.ts b/mobile/src/session/mobile-native-chat-autocomplete.test.ts
index 608917449d4..7fac03e7354 100644
--- a/mobile/src/session/mobile-native-chat-autocomplete.test.ts
+++ b/mobile/src/session/mobile-native-chat-autocomplete.test.ts
@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'
 import {
   applyAutocomplete,
   detectAutocompleteTrigger,
@@ -90,4 +90,77 @@ describe('rankSlashCommandSuggestions', () => {
     expect(rankSlashCommandSuggestions(commands, 'CLE').map((c) => c.name)).toEqual(['clear'])
     expect(rankSlashCommandSuggestions(commands, 'zzz')).toEqual([])
   })
+
+  it('preserves command identity and metadata for duplicate names', () => {
+    const catalog = [
+      { name: 'team-review', description: 'First' },
+      { name: 'team-review', argumentHint: '<branch>' },
+      { name: 'review', kindUnspecified: true as const }
+    ]
+    const result = rankSlashCommandSuggestions(catalog, 'review', 3)
+    expect(result[0]).toBe(catalog[2])
+    expect(result[1]).toBe(catalog[0])
+    expect(result[2]).toBe(catalog[1])
+  })
+})
+
+describe.each([
+  { name: 'file', rank: rankSuggestions },
+  {
+    name: 'slash',
+    rank: (names: readonly string[], query: string, limit: number): string[] =>
+      rankSlashCommandSuggestions(
+        names.map((name) => ({ name })),
+        query,
+        limit
+      ).map((command) => command.name)
+  }
+])('$name suggestion bounds', ({ rank }) => {
+  it('keeps later prefixes ahead of the earliest substring matches', () => {
+    const candidates = ['team-review', 'team-review', 'pre-review', 'review-a', 'REVIEW-b']
+    expect(rank(candidates, 'REVIEW', 4)).toEqual([
+      'review-a',
+      'REVIEW-b',
+      'team-review',
+      'team-review'
+    ])
+  })
+
+  it('stops substring matching once enough fallback suggestions are retained', () => {
+    const candidates = Array.from({ length: 10_000 }, (_, index) => `team-review-${index}`)
+    candidates.push('review-last', 'review-final')
+    const includes = String.prototype.includes
+    let substringChecks = 0
+    const spy = vi.spyOn(String.prototype, 'includes').mockImplementation(function (
+      this: string,
+      search: string,
+      position?: number
+    ) {
+      substringChecks += 1
+      return includes.call(this, search, position)
+    })
+    let result: string[]
+    try {
+      result = rank(candidates, 'review', 8)
+    } finally {
+      spy.mockRestore()
+    }
+    expect(result).toEqual(['review-last', 'review-final', ...candidates.slice(0, 6)])
+    expect(substringChecks).toBeLessThanOrEqual(8)
+  })
+
+  it.each([0, -0, -1, -0.5, -Infinity, Number.NaN])(
+    'preserves empty results for limit %s',
+    (limit) => {
+      expect(rank(['team-review', 'review-a', 'review-b'], 'review', limit)).toEqual([])
+    }
+  )
+
+  it.each([0.5, 1.5, 2.5, Infinity])('preserves slice truncation for limit %s', (limit) => {
+    const candidates = ['team-review', 'pre-review', 'review-a', 'review-b']
+    expect(rank(candidates, 'review', limit)).toEqual(
+      ['review-a', 'review-b', 'team-review', 'pre-review'].slice(0, limit)
+    )
+    expect(rank(candidates, '', limit)).toEqual(candidates.slice(0, limit))
+  })
 })
diff --git a/mobile/src/session/mobile-native-chat-autocomplete.ts b/mobile/src/session/mobile-native-chat-autocomplete.ts
index 8de107c9fb0..5bbeb8a5d65 100644
--- a/mobile/src/session/mobile-native-chat-autocomplete.ts
+++ b/mobile/src/session/mobile-native-chat-autocomplete.ts
@@ -84,7 +84,7 @@ export function rankSuggestions(candidates: readonly string[], query: string, li
     const base = lower.slice(lower.lastIndexOf('/') + 1)
     if (lower.startsWith(q) || base.startsWith(q)) {
       prefix.push(candidate)
-    } else if (lower.includes(q)) {
+    } else if (substring.length < limit && lower.includes(q)) {
       substring.push(candidate)
     }
     if (prefix.length >= limit) {
@@ -112,7 +112,7 @@ export function rankSlashCommandSuggestions(
     const lower = command.name.toLowerCase()
     if (lower.startsWith(q)) {
       prefix.push(command)
-    } else if (lower.includes(q)) {
+    } else if (substring.length < limit && lower.includes(q)) {
       substring.push(command)
     }
     if (prefix.length >= limit) {