diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index ef2dbf1c888..f1522dddeeb 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -39,6 +39,7 @@ jobs:
       mobile_web_app: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.mobile_web_app }}
       static_analysis: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.static_analysis }}
       typecheck: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.typecheck }}
+      mobile_ci_tools: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.mobile_ci_tools }}
       git_compatibility: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.git_compatibility }}
       codex_index_heal_contract: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.codex_index_heal_contract }}
       xterm_patch_sync: ${{ steps.readiness.outputs.reused != 'true' && steps.filter.outputs.xterm_patch_sync }}
@@ -115,7 +116,11 @@ jobs:
           CHANGED="$(git diff --name-only --no-renames --diff-filter=ACDMR "$DIFF_BASE" HEAD)"
           echo "Changed paths:"
           printf '%s\n' "$CHANGED"
-          printf '%s\n' "$CHANGED" | node config/scripts/pr-code-change-scope.mjs | tee -a "$GITHUB_OUTPUT"
+          MOBILE_CI_ARGS=()
+          if git diff --quiet --no-renames --diff-filter=ACDRTUXB "$DIFF_BASE" HEAD; then
+            MOBILE_CI_ARGS=(--mobile-ci-tools)
+          fi
+          printf '%s\n' "$CHANGED" | node config/scripts/pr-code-change-scope.mjs "${MOBILE_CI_ARGS[@]}" | tee -a "$GITHUB_OUTPUT"
 
       # Reuse the path-detector checkout instead of queuing another runner.
       - name: Filter changed E2E specs
@@ -461,6 +466,28 @@ jobs:
           path: ci-shards/unit-selection.json
           retention-days: 14
 
+      - name: Set up Bun for Mobile CI tool tests
+        if: needs.code_paths.outputs.mobile_ci_tools == 'true'
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2.2.0
+        with:
+          bun-version-file: config/.bun-version
+
+      - name: Test Mobile CI tools and runtime routing
+        if: needs.code_paths.outputs.mobile_ci_tools == 'true'
+        env:
+          ORCA_BACKGROUND_LAUNCH: '1'
+          ORCA_BALANCE_UNIT_SHARDS: '1'
+        run: >-
+          node config/scripts/run-vitest.mjs run --config config/vitest.config.ts
+          --maxWorkers=4 --isolate --retry=0 --bail=0
+          config/scripts/mobile-release-check-scope.test.mjs
+          config/scripts/mobile-test-change-scope.test.mjs
+          config/scripts/pr-ready-check-reuse.test.mjs
+          config/scripts/ci-dependency-download-cache.test.mjs
+          config/scripts/win32-test-lane-registration.test.mjs
+          config/scripts/vitest-node-runtime-boundary.test.ts
+          config/scripts/vitest-sqlite-runtime-boundary.test.ts
+
   git_compatibility:
     name: Git compatibility
     needs: [code_paths, preflight]
@@ -811,6 +838,7 @@ jobs:
       node_versions: '["24"]'
       runner: ubuntu-24.04-arm
       shards: ${{ needs.preflight.outputs.shards }}
+      run_shards: ${{ needs.code_paths.outputs.mobile_ci_tools != 'true' }}
       browser_contract: ${{ needs.code_paths.outputs.orcad_browser == 'true' }}
 
   # Why a sibling and not part of the test workflow: it is advisory, so it must not delay the
diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index 3848e542cf4..9ea37f36248 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -20,6 +20,12 @@ on:
         default: false
         type: boolean
 
+      run_shards:
+        description: Run the planned root unit shards.
+        required: false
+        default: true
+        type: boolean
+
       shards:
         description: JSON array of shard assignments, produced by unit-plan.yml.
         required: true
@@ -30,6 +36,7 @@ permissions:
 
 jobs:
   test:
+    if: inputs.run_shards
     name: tests node ${{ matrix.node }} ${{ matrix.shard.index }}/${{ matrix.shard.count }}
     runs-on: ${{ inputs.runner }}
     timeout-minutes: 60
diff --git a/config/scripts/pr-auxiliary-preflight-admission.test.mjs b/config/scripts/pr-auxiliary-preflight-admission.test.mjs
index 94889330895..bd2b9e9a095 100644
--- a/config/scripts/pr-auxiliary-preflight-admission.test.mjs
+++ b/config/scripts/pr-auxiliary-preflight-admission.test.mjs
@@ -1,6 +1,17 @@
-import { readFileSync } from 'node:fs'
+import {
+  copyFileSync,
+  mkdirSync,
+  mkdtempSync,
+  readFileSync,
+  rmSync,
+  symlinkSync,
+  writeFileSync
+} from 'node:fs'
+import { tmpdir } from 'node:os'
+import { dirname, join, resolve } from 'node:path'
 import { runInNewContext } from 'node:vm'
-import { describe, expect, it } from 'vitest'
+import { afterEach, describe, expect, it } from 'vitest'
+import { runProcessSync } from '@orca/process-host'
 import { parse } from 'yaml'
 import { classifyPrJobs } from './pr-code-change-scope.mjs'
 
@@ -28,8 +39,8 @@ function evaluate(expression, context) {
   )
 }
 
-function routedOutputs(files, reused) {
-  const scope = classifyPrJobs(files)
+function routedOutputs(files, reused, options) {
+  const scope = classifyPrJobs(files, options)
   const context = {
     steps: {
       readiness: { outputs: { reused } },
@@ -41,10 +52,9 @@ function routedOutputs(files, reused) {
     }
   }
   return Object.fromEntries(
-    ['test', 'static_analysis', 'typecheck', ...routes.map(([job]) => job)].map((name) => [
-      name,
-      String(evaluate(workflow.jobs.code_paths.outputs[name], context))
-    ])
+    ['test', 'static_analysis', 'typecheck', 'mobile_ci_tools', ...routes.map(([job]) => job)].map(
+      (name) => [name, String(evaluate(workflow.jobs.code_paths.outputs[name], context))]
+    )
   )
 }
 
@@ -207,3 +217,183 @@ it('guards both browser steps after setup or discovery failure and for default c
   expect(evaluate(chrome.if, context)).toBe(false)
   expect(evaluate(browser.if, context)).toBe(false)
 })
+
+describe('Mobile CI tool preflight routing', () => {
+  const verified = { allowMobileCiTools: true }
+
+  it.each([
+    { files: ['config/scripts/run-mobile-ci-tests.mjs', 'config/mobile-ci.vitest.config.mjs'] },
+    { files: ['config/scripts/mobile-release-check-scope.test.mjs'] },
+    { files: ['config/scripts/mobile-test-change-scope.test.mjs'] }
+  ])('keeps affected controls required without starting root shards for $files', ({ files }) => {
+    const outputs = routedOutputs(files, 'false', verified)
+    expect(outputs.mobile_ci_tools).toBe('true')
+    expect(outputs.test).toBe('true')
+    const context = { needs: { code_paths: { outputs } } }
+    expect(evaluate(workflow.jobs.preflight.if, context)).toBe(true)
+    expect(evaluate(workflow.jobs.test.with.run_shards, context)).toBe(false)
+    expect(evaluate(unit.jobs.test.if, { inputs: { run_shards: false } })).toBe(false)
+    const required = workflow.jobs.verify.steps.find(
+      (step) => step.name === 'Require successful checks'
+    )
+    expect(evaluate(required.env.PREFLIGHT_SHOULD_RUN, context)).toBe(true)
+  })
+
+  it('keeps workflow-only changes on their original skipped root route', () => {
+    const outputs = routedOutputs(['.github/workflows/mobile.yml'], 'false', verified)
+    expect(outputs.mobile_ci_tools).toBe('false')
+    expect(outputs.test).toBe('false')
+    expect(outputs.static_analysis).toBe('false')
+    expect(outputs.typecheck).toBe('false')
+    expect(evaluate(workflow.jobs.preflight.if, { needs: { code_paths: { outputs } } })).toBe(false)
+  })
+
+  it('keeps root shard execution enabled for callers that do not opt out', () => {
+    expect(unit.on.workflow_call.inputs.run_shards.default).toBe(true)
+    expect(evaluate(unit.jobs.test.if, { inputs: { run_shards: true } })).toBe(true)
+    expect(unit.jobs.relay_integration.if).toBeUndefined()
+    expect(unit.jobs.relay_integration.needs).toBeUndefined()
+  })
+
+  it('requires complete modification evidence and an exact path scope', () => {
+    const tool = 'config/scripts/run-mobile-ci-tests.mjs'
+    expect(classifyPrJobs([tool]).test).toBe(true)
+    expect(classifyPrJobs([tool]).mobile_ci_tools).toBe(false)
+    for (const files of [
+      [],
+      [tool, 'src/main/runtime/orca-runtime.ts'],
+      [tool, 'pnpm-lock.yaml'],
+      [tool, 'package.json'],
+      [tool, 'config/vitest.config.ts'],
+      [tool, 'config/scripts/pr-code-change-scope.mjs'],
+      [tool, 'config/scripts/new-mobile-tool.mjs'],
+      [tool, 'README.md'],
+      [tool, 'mobile/vitest.config.ts']
+    ]) {
+      const selected = classifyPrJobs(files, verified)
+      expect(selected.mobile_ci_tools).toBe(false)
+      expect(selected.test).toBe(true)
+    }
+  })
+
+  it('reuses only identical successful checks for the focused preflight gate', () => {
+    const files = ['config/scripts/run-mobile-ci-tests.mjs']
+    expect(routedOutputs(files, 'true', verified).mobile_ci_tools).toBe('false')
+    expect(routedOutputs(files, 'false', verified).mobile_ci_tools).toBe('true')
+  })
+})
+
+const mobileCiScopeDirectories = []
+afterEach(() => {
+  for (const directory of mobileCiScopeDirectories.splice(0)) {
+    rmSync(directory, { recursive: true, force: true })
+  }
+})
+
+function createMobileCiScopeRepository(withTool = true) {
+  const directory = mkdtempSync(join(tmpdir(), 'orca-mobile-ci-scope-'))
+  mobileCiScopeDirectories.push(directory)
+  const root = resolve(import.meta.dirname, '../..')
+  for (const file of [
+    'package.json',
+    'config/scripts/pr-code-change-scope.mjs',
+    'config/scripts/git-pull-request-diff-base.mjs'
+  ]) {
+    mkdirSync(dirname(join(directory, file)), { recursive: true })
+    copyFileSync(join(root, file), join(directory, file))
+  }
+  const git = (...args) => {
+    const result = runProcessSync({ program: 'git', args, cwd: directory })
+    expect(result.code, result.stderr).toBe(0)
+    return result.stdout.trim()
+  }
+  const commit = () => {
+    git('add', '-A')
+    git(
+      '-c',
+      'commit.gpgsign=false',
+      '-c',
+      'core.hooksPath=/dev/null',
+      'commit',
+      '-qm',
+      'scope input'
+    )
+    return git('rev-parse', 'HEAD')
+  }
+  git('init', '--quiet')
+  git('config', 'user.name', 'Scope control')
+  git('config', 'user.email', 'scope@example.invalid')
+  const tool = join(directory, 'config/scripts/run-mobile-ci-tests.mjs')
+  if (withTool) {
+    writeFileSync(tool, 'export const revision = 1\n')
+  }
+  const base = commit()
+  const detect = () => {
+    const output = join(directory, 'github-output')
+    const step = workflow.jobs.code_paths.steps.find((candidate) => candidate.id === 'filter')
+    const result = runProcessSync({
+      program: 'bash',
+      args: ['-e', '-c', step.run],
+      cwd: directory,
+      env: {
+        ...process.env,
+        BASE_SHA: base,
+        GITHUB_EVENT_NAME: 'pull_request',
+        GITHUB_OUTPUT: output,
+        ORCA_BACKGROUND_LAUNCH: '1'
+      }
+    })
+    return { result, output }
+  }
+  return { directory, tool, git, commit, detect }
+}
+
+describe.skipIf(process.platform === 'win32')('Mobile CI complete Git change evidence', () => {
+  it('admits an actual modification through the workflow detector', () => {
+    const repo = createMobileCiScopeRepository()
+    writeFileSync(repo.tool, 'export const revision = 2\n')
+    repo.commit()
+    const { result, output } = repo.detect()
+    expect(result.code, result.stderr).toBe(0)
+    expect(readFileSync(output, 'utf8')).toContain('mobile_ci_tools=true\n')
+    expect(readFileSync(output, 'utf8')).toContain('test=true\n')
+  })
+
+  it.each(['addition', 'deletion', 'rename', 'type change'])(
+    'retains full root units for an actual %s',
+    (change) => {
+      const repo = createMobileCiScopeRepository(change !== 'addition')
+      if (change === 'addition') {
+        writeFileSync(repo.tool, 'export const revision = 1\n')
+      } else if (change === 'deletion') {
+        rmSync(repo.tool)
+      } else if (change === 'rename') {
+        repo.git(
+          'mv',
+          'config/scripts/run-mobile-ci-tests.mjs',
+          'config/mobile-ci.vitest.config.mjs'
+        )
+      } else {
+        rmSync(repo.tool)
+        symlinkSync('pr-code-change-scope.mjs', repo.tool)
+      }
+      repo.commit()
+      const { result, output } = repo.detect()
+      expect(result.code, result.stderr).toBe(0)
+      expect(readFileSync(output, 'utf8')).toContain('mobile_ci_tools=false\n')
+      expect(readFileSync(output, 'utf8')).toContain('test=true\n')
+    }
+  )
+
+  it('does not emit a passing classification when the Git evidence is unavailable', () => {
+    const repo = createMobileCiScopeRepository()
+    writeFileSync(repo.tool, 'export const revision = 2\n')
+    repo.commit()
+    expect(repo.detect().result.code).toBe(0)
+    rmSync(join(repo.directory, 'github-output'))
+    rmSync(join(repo.directory, '.git'), { recursive: true, force: true })
+    const { result } = repo.detect()
+    expect(result.code).not.toBe(0)
+    expect(result.stderr).toContain('not a git repository')
+  })
+})
diff --git a/config/scripts/pr-code-change-scope.mjs b/config/scripts/pr-code-change-scope.mjs
index c9d52d9f36d..13e5d6b1e5e 100644
--- a/config/scripts/pr-code-change-scope.mjs
+++ b/config/scripts/pr-code-change-scope.mjs
@@ -35,6 +35,14 @@ export const PR_CHECK_JOBS = [
 
 const ALWAYS_ON_CODE_JOBS = new Set(['static_analysis', 'typecheck', 'test'])
 
+const MOBILE_CI_TOOL_FILES = new Set([
+  '.github/workflows/mobile.yml',
+  'config/mobile-ci.vitest.config.mjs',
+  'config/scripts/run-mobile-ci-tests.mjs',
+  'config/scripts/mobile-release-check-scope.test.mjs',
+  'config/scripts/mobile-test-change-scope.test.mjs'
+])
+
 const GLOBAL_FORCE_PREFIXES = [
   '.github/workflows/pr.yml',
   '.github/actions/install-node-dependencies/',
@@ -491,7 +499,7 @@ export function needsMobileDependencies(changedFiles) {
   return changedFiles.length === 0 || changedFiles.some((file) => file.startsWith('mobile/'))
 }
 
-export function classifyPrJobs(changedFiles) {
+export function classifyPrJobs(changedFiles, { allowMobileCiTools = false } = {}) {
   const emptyDiff = changedFiles.length === 0
   const shouldRun = shouldRunPrChecks(changedFiles)
   const forceAll = emptyDiff || changedFiles.some(isGlobalForcePath)
@@ -509,8 +517,15 @@ export function classifyPrJobs(changedFiles) {
   // that is exactly the diff that changes the page this job builds. Gated on should_run it would
   // skip on every PR that can break it and run on none.
   jobs.mobile_web_app = jobs.mobile_web_app || changesMobileWebApp(changedFiles)
+  const mobileCiTools =
+    allowMobileCiTools &&
+    !emptyDiff &&
+    jobs.test &&
+    (jobs.static_analysis || jobs.typecheck) &&
+    changedFiles.every((file) => MOBILE_CI_TOOL_FILES.has(file))
   return {
     should_run: shouldRun,
+    mobile_ci_tools: mobileCiTools,
     native_cache_changed: shouldRun && (emptyDiff || changedFiles.some(isNativeCacheInputPath)),
     mobile_dependencies:
       (shouldRun || jobs.static_analysis) && needsMobileDependencies(changedFiles),
@@ -618,7 +633,9 @@ if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href)
     input += chunk
   }
   const files = input.split(/\r?\n/).filter(Boolean)
-  const classification = classifyPrJobs(files)
+  const classification = classifyPrJobs(files, {
+    allowMobileCiTools: process.argv.includes('--mobile-ci-tools')
+  })
   for (const [name, value] of Object.entries(classification)) {
     process.stdout.write(`${name}=${value ? 'true' : 'false'}\n`)
   }