diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index b59dcc3d0..ee5702fd8 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -22,8 +22,49 @@ env:
   HTTPX_VERSION: 0.28.1
 
 jobs:
+  classify:
+    name: Classify deploy relevance
+    runs-on: ubuntu-latest
+    outputs:
+      should_deploy: ${{ steps.classify.outputs.should_deploy }}
+      decision: ${{ steps.classify.outputs.decision }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: Set up Node 24
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+
+      - name: Classify exact push diff
+        id: classify
+        env:
+          BASE_SHA: ${{ github.event.before }}
+        run: |
+          set -euo pipefail
+          decision="$(node scripts/vercel-ignore-build.mjs --decision --base "${BASE_SHA:-}" --head "$GITHUB_SHA")"
+          case "$decision" in
+            SKIP)
+              should_deploy=false
+              ;;
+            BUILD)
+              should_deploy=true
+              ;;
+            *)
+              echo "Unexpected deploy decision: $decision" >&2
+              exit 1
+              ;;
+          esac
+          echo "decision=$decision" >> "$GITHUB_OUTPUT"
+          echo "should_deploy=$should_deploy" >> "$GITHUB_OUTPUT"
+          echo "Deploy relevance: $decision"
+
   deploy:
     name: Vercel Production Deploy
+    needs: classify
+    if: needs.classify.outputs.should_deploy == 'true'
     runs-on: ubuntu-latest
     outputs:
       deployment_url: ${{ steps.deploy.outputs.deployment_url }}
diff --git a/app/lib/vercel-deploy-quota-guard.test.ts b/app/lib/vercel-deploy-quota-guard.test.ts
new file mode 100644
index 000000000..6e9d6b988
--- /dev/null
+++ b/app/lib/vercel-deploy-quota-guard.test.ts
@@ -0,0 +1,158 @@
+import assert from 'node:assert/strict'
+import { execFileSync, spawnSync } from 'node:child_process'
+import { mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import test from 'node:test'
+import { fileURLToPath } from 'node:url'
+
+const ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '../..')
+const HELPER = path.join(ROOT, 'scripts', 'vercel-ignore-build.mjs')
+
+function runDecision(paths: string[]) {
+  return spawnSync(process.execPath, [HELPER, '--decision', '--changed', ...paths], {
+    cwd: ROOT,
+    encoding: 'utf8',
+  })
+}
+
+function runVercelIgnore(paths: string[]) {
+  return spawnSync(process.execPath, [HELPER, '--vercel-ignore', '--changed', ...paths], {
+    cwd: ROOT,
+    encoding: 'utf8',
+  })
+}
+
+function git(cwd: string, ...args: string[]) {
+  return execFileSync('git', args, { cwd, encoding: 'utf8' }).trim()
+}
+
+function createRepoWithChange(relativePath: string) {
+  const repo = mkdtempSync(path.join(tmpdir(), 'dgaf-vercel-quota-'))
+  git(repo, 'init')
+  git(repo, 'config', 'user.email', 'test@example.invalid')
+  git(repo, 'config', 'user.name', 'DGAF test')
+  writeFileSync(path.join(repo, 'README.md'), 'baseline\n')
+  git(repo, 'add', 'README.md')
+  git(repo, 'commit', '-m', 'baseline')
+  const previous = git(repo, 'rev-parse', 'HEAD')
+
+  const target = path.join(repo, relativePath)
+  mkdirSync(path.dirname(target), { recursive: true })
+  writeFileSync(target, 'changed\n')
+  git(repo, 'add', relativePath)
+  git(repo, 'commit', '-m', 'change')
+  const current = git(repo, 'rev-parse', 'HEAD')
+  return { repo, previous, current }
+}
+
+function createRepoWithRuntimeRename() {
+  const repo = mkdtempSync(path.join(tmpdir(), 'dgaf-vercel-quota-rename-'))
+  git(repo, 'init')
+  git(repo, 'config', 'user.email', 'test@example.invalid')
+  git(repo, 'config', 'user.name', 'DGAF test')
+  mkdirSync(path.join(repo, 'app'), { recursive: true })
+  writeFileSync(path.join(repo, 'app/page.tsx'), 'export default function Page() { return null }\n')
+  git(repo, 'add', 'app/page.tsx')
+  git(repo, 'commit', '-m', 'runtime baseline')
+  const previous = git(repo, 'rev-parse', 'HEAD')
+
+  mkdirSync(path.join(repo, 'docs'), { recursive: true })
+  git(repo, 'mv', 'app/page.tsx', 'docs/page.tsx')
+  git(repo, 'commit', '-m', 'move runtime file')
+  const current = git(repo, 'rev-parse', 'HEAD')
+  return { repo, previous, current }
+}
+
+function runGitDecision(cwd: string, previous?: string, current?: string) {
+  const args = [HELPER, '--decision', '--base', previous ?? '', '--head', current ?? '']
+  return spawnSync(process.execPath, args, { cwd, encoding: 'utf8' })
+}
+
+test('only proven inert surfaces are classified SKIP', () => {
+  for (const changed of [
+    ['docs/experiment/status.md'],
+    ['schemas/example.schema.json'],
+    ['tests/test_example.py'],
+    ['.github/workflows/claim-hygiene.yml'],
+    ['docs/status.md', 'schemas/example.json', 'tests/test_example.py'],
+  ]) {
+    const result = runDecision(changed)
+    assert.equal(result.status, 0, result.stderr || result.stdout)
+    assert.equal(result.stdout.trim(), 'SKIP')
+  }
+})
+
+test('runtime, scripts, deploy control, config, unknown, mixed, and empty changes classify BUILD', () => {
+  const cases = [
+    ['scripts/validate_example.py'],
+    ['scripts/vercel-ignore-build.mjs'],
+    ['.github/workflows/deploy.yml'],
+    ['app/page.tsx'],
+    ['api/health.py'],
+    ['public/logo.svg'],
+    ['vercel.json'],
+    ['package.json'],
+    ['package-lock.json'],
+    ['next.config.ts'],
+    ['tsconfig.json'],
+    ['new-runtime-surface/example.ts'],
+    ['docs/status.md', 'app/page.tsx'],
+    [],
+  ]
+
+  for (const changed of cases) {
+    const result = runDecision(changed)
+    assert.equal(result.status, 0, result.stderr || result.stdout)
+    assert.equal(result.stdout.trim(), 'BUILD')
+  }
+})
+
+test('Vercel ignore exit semantics are SKIP=0 and BUILD=1', () => {
+  assert.equal(runVercelIgnore(['docs/status.md']).status, 0)
+  assert.equal(runVercelIgnore(['app/page.tsx']).status, 1)
+})
+
+test('Git comparison classifies a documentation-only commit SKIP', () => {
+  const fixture = createRepoWithChange('docs/status.md')
+  try {
+    const result = runGitDecision(fixture.repo, fixture.previous, fixture.current)
+    assert.equal(result.status, 0, result.stderr || result.stdout)
+    assert.equal(result.stdout.trim(), 'SKIP')
+  } finally {
+    rmSync(fixture.repo, { recursive: true, force: true })
+  }
+})
+
+test('Git comparison fails closed to BUILD for invalid evidence', () => {
+  const fixture = createRepoWithChange('docs/status.md')
+  try {
+    assert.equal(runGitDecision(fixture.repo, undefined, fixture.current).stdout.trim(), 'BUILD')
+    assert.equal(runGitDecision(fixture.repo, 'not-a-commit', fixture.current).stdout.trim(), 'BUILD')
+  } finally {
+    rmSync(fixture.repo, { recursive: true, force: true })
+  }
+})
+
+test('runtime rename into an inert surface still classifies BUILD', () => {
+  const fixture = createRepoWithRuntimeRename()
+  try {
+    const result = runGitDecision(fixture.repo, fixture.previous, fixture.current)
+    assert.equal(result.status, 0, result.stderr || result.stdout)
+    assert.equal(result.stdout.trim(), 'BUILD')
+  } finally {
+    rmSync(fixture.repo, { recursive: true, force: true })
+  }
+})
+
+test('Vercel and GitHub deploy paths are wired to the same classifier', () => {
+  const config = JSON.parse(readFileSync(path.join(ROOT, 'vercel.json'), 'utf8'))
+  assert.equal(config.ignoreCommand, 'node scripts/vercel-ignore-build.mjs')
+  assert.equal(config.git?.deploymentEnabled?.main, false)
+
+  const workflow = readFileSync(path.join(ROOT, '.github/workflows/deploy.yml'), 'utf8')
+  assert.match(workflow, /name: Classify deploy relevance/)
+  assert.match(workflow, /node scripts\/vercel-ignore-build\.mjs --decision --base/)
+  assert.match(workflow, /needs: classify/)
+  assert.match(workflow, /needs\.classify\.outputs\.should_deploy == 'true'/)
+})
diff --git a/scripts/vercel-ignore-build.mjs b/scripts/vercel-ignore-build.mjs
new file mode 100644
index 000000000..b7f97a73d
--- /dev/null
+++ b/scripts/vercel-ignore-build.mjs
@@ -0,0 +1,60 @@
+#!/usr/bin/env node
+
+import { spawnSync } from 'node:child_process'
+
+const SAFE_SKIP_PREFIXES = ['.github/', 'docs/', 'schemas/', 'tests/']
+const FORCE_BUILD_PATHS = new Set(['.github/workflows/deploy.yml'])
+
+function canSafelySkip(changedPaths) {
+  return changedPaths.length > 0 && changedPaths.every(path => {
+    if (FORCE_BUILD_PATHS.has(path)) return false
+    return SAFE_SKIP_PREFIXES.some(prefix => path.startsWith(prefix))
+  })
+}
+
+function isAvailableCommit(sha) {
+  if (!sha) return false
+  return spawnSync('git', ['cat-file', '-e', `${sha}^{commit}`], { stdio: 'ignore' }).status === 0
+}
+
+function changedPathsFromGit(base, head) {
+  if (!isAvailableCommit(base) || !isAvailableCommit(head)) return null
+
+  const diff = spawnSync(
+    'git',
+    ['diff', '--name-only', '-z', '--no-renames', base, head, '--'],
+    { encoding: 'utf8' },
+  )
+  if (diff.status !== 0 || diff.error) return null
+  return diff.stdout.split('\0').filter(Boolean)
+}
+
+function readOption(args, name) {
+  const index = args.indexOf(name)
+  return index >= 0 ? args[index + 1] ?? '' : ''
+}
+
+const args = process.argv.slice(2)
+const decisionMode = args.includes('--decision')
+const explicitIgnoreMode = args.includes('--vercel-ignore')
+const changedIndex = args.indexOf('--changed')
+
+let changedPaths
+if (changedIndex >= 0) {
+  changedPaths = args.slice(changedIndex + 1)
+} else {
+  const base = readOption(args, '--base') || process.env.VERCEL_GIT_PREVIOUS_SHA || ''
+  const head = readOption(args, '--head') || process.env.VERCEL_GIT_COMMIT_SHA || ''
+  changedPaths = changedPathsFromGit(base, head)
+}
+
+const decision = changedPaths && canSafelySkip(changedPaths) ? 'SKIP' : 'BUILD'
+
+if (decisionMode) {
+  process.stdout.write(`${decision}\n`)
+  process.exit(0)
+}
+
+if (explicitIgnoreMode || !decisionMode) {
+  process.exit(decision === 'SKIP' ? 0 : 1)
+}
diff --git a/vercel.json b/vercel.json
index 60f8e604a..edaf72f27 100644
--- a/vercel.json
+++ b/vercel.json
@@ -4,6 +4,7 @@
   "framework": "nextjs",
   "buildCommand": "npm run build",
   "outputDirectory": ".next",
+  "ignoreCommand": "node scripts/vercel-ignore-build.mjs",
   "git": {
     "deploymentEnabled": {
       "main": false