diff --git a/AGENTS.md b/AGENTS.md
index a7d7256eeb4..d0269b7f628 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -97,6 +97,7 @@ Follow these coding conventions for new/updated code (a three-line fix in a lega
   - Annotate every variable with `: Final` (LIT010). Unpacking and walrus targets cannot carry the annotation, so they are implicitly final. Don't rebind them. Never rebind or mutate function parameters (LIT011); `self`/`cls` attribute stores are the exception. If rebinding or in-place mutation is truly unavoidable, suppress with `# rebind-ok: <reason>`
   - Qualify every TypedDict field with `ReadOnly[...]` (LIT012), which nests freely with `Required` / `NotRequired` / `Annotated` in any order. If making the key writable is truly unavoidable, suppress with `# writable-ok: <reason>`
   - Comprehensions take at most one `for` clause and one `if` clause (LIT014); split stacked clauses into a helper generator, a named intermediate, or a plain loop. Suppress with `# comprehension-ok: <reason>` only when unavoidable
+  - Every pydantic model must be frozen (LIT015), set via `model_config = ConfigDict(frozen=True)`, a dict-literal `model_config`, an inner `class Config`, or the class keywords. Subclasses inherit it unless they override it. If making the model mutable is truly unavoidable, suppress with `# frozen-ok: <reason>` on the `class` line
 - Use dependency injection
 - Fully typed; no `Any` or coarse types like `dict[str, Any]` or just `dict`. Every function parameter must be strongly typed
 - Use tagged unions + match
diff --git a/scripts/type_discipline_gate.py b/scripts/type_discipline_gate.py
index 3293f32d565..fda6bb5def0 100644
--- a/scripts/type_discipline_gate.py
+++ b/scripts/type_discipline_gate.py
@@ -17,7 +17,8 @@ LIT012 (TypedDict field without a `ReadOnly[...]` qualifier; suppress with
 `# writable-ok: <reason>`), and LIT014 (comprehension with more than one `for`
 or `if` clause; suppress with `# comprehension-ok: <reason>` on a spanned
 line, which belongs to the innermost violating comprehension spanning it and
-to any single-line violating comprehension on that line) carry limits at
+to any single-line violating comprehension on that line), and LIT015
+(pydantic model not frozen; suppress with `# frozen-ok: <reason>`) carry limits at
 or above their current count to ratchet down; LIT005 (`*-ok` suppression
 without a reason) is frozen at limit 0
 so any net-new reasonless suppression trips the gate; LIT013 (`*-ok` suppression
diff --git a/type-discipline-budget.json b/type-discipline-budget.json
index 11bc9722d81..40752398386 100644
--- a/type-discipline-budget.json
+++ b/type-discipline-budget.json
@@ -37,5 +37,8 @@
   },
   "LIT014": {
     "limit": 369
+  },
+  "LIT015": {
+    "limit": 230
   }
 }