diff --git a/tests/test_provider_ternary_freeze.py b/tests/test_provider_ternary_freeze.py
new file mode 100644
index 00000000..58f6b028
--- /dev/null
+++ b/tests/test_provider_ternary_freeze.py
@@ -0,0 +1,38 @@
+"""Paso 6.a: freeze provider ternaries in ui/src so they cannot grow."""
+from __future__ import annotations
+
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+SRC = ROOT / "ui" / "src"
+
+MINIMAX_TERNARY = "=== 'minimax' ?"
+MAESTRO_WRITER = "writingProvider === 'maestro'"
+MAX_MINIMAX_TERNARIES = 30
+MAX_MAESTRO_WRITERS = 6
+
+
+def _count_literal(needle: str) -> int:
+    total = 0
+    for path in SRC.rglob("*"):
+        if path.suffix not in {".ts", ".tsx"}:
+            continue
+        total += path.read_text(encoding="utf-8").count(needle)
+    return total
+
+
+def test_minimax_ternaries_under_ui_src_do_not_increase() -> None:
+    found = _count_literal(MINIMAX_TERNARY)
+    assert found <= MAX_MINIMAX_TERNARIES, (
+        f"{MINIMAX_TERNARY!r} under ui/src grew to {found}; cap is "
+        f"{MAX_MINIMAX_TERNARIES}. Map new cases through provider_profile / "
+        "writingProviderFromText instead of adding ternaries."
+    )
+
+
+def test_maestro_writing_provider_comparisons_do_not_increase() -> None:
+    found = _count_literal(MAESTRO_WRITER)
+    assert found <= MAX_MAESTRO_WRITERS, (
+        f"{MAESTRO_WRITER!r} under ui/src grew to {found}; cap is "
+        f"{MAX_MAESTRO_WRITERS}. Use the canonical writing-provider mapper."
+    )
diff --git a/ui/tests/providerTernaryFreeze.test.mjs b/ui/tests/providerTernaryFreeze.test.mjs
new file mode 100644
index 00000000..adcf610e
--- /dev/null
+++ b/ui/tests/providerTernaryFreeze.test.mjs
@@ -0,0 +1,43 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+import { readdirSync, readFileSync, statSync } from 'node:fs'
+import { extname, join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+const SRC = fileURLToPath(new URL('../src', import.meta.url))
+const MINIMAX_TERNARY = "=== 'minimax' ?"
+const MAESTRO_WRITER = "writingProvider === 'maestro'"
+const MAX_MINIMAX_TERNARIES = 30
+const MAX_MAESTRO_WRITERS = 6
+
+function walk(dir) {
+  const files = []
+  for (const name of readdirSync(dir)) {
+    const path = join(dir, name)
+    if (statSync(path).isDirectory()) files.push(...walk(path))
+    else if (extname(path) === '.ts' || extname(path) === '.tsx') files.push(path)
+  }
+  return files
+}
+
+function countLiteral(needle) {
+  return walk(SRC).reduce((total, path) => (
+    total + readFileSync(path, 'utf8').split(needle).length - 1
+  ), 0)
+}
+
+test('ui/src does not grow === \'minimax\' ? ternaries', () => {
+  const found = countLiteral(MINIMAX_TERNARY)
+  assert.ok(
+    found <= MAX_MINIMAX_TERNARIES,
+    `${MINIMAX_TERNARY} under ui/src grew to ${found}; cap is ${MAX_MINIMAX_TERNARIES}`,
+  )
+})
+
+test('ui/src does not grow writingProvider === \'maestro\' comparisons', () => {
+  const found = countLiteral(MAESTRO_WRITER)
+  assert.ok(
+    found <= MAX_MAESTRO_WRITERS,
+    `${MAESTRO_WRITER} under ui/src grew to ${found}; cap is ${MAX_MAESTRO_WRITERS}`,
+  )
+})