@@ -604,6 +604,105 @@ def test_S029_ignores_non_seer_pool() -> None:
     assert _run(src, filename="src/sentry/example.py") == []
 
 
+def test_S030_allows_exact_legacy_callsite_baseline() -> None:
+    src = """\
+from sentry.seer.signed_seer_api import LlmGenerateRequest, make_llm_generate_request
+
+
+def generate_title_from_query():
+    body = LlmGenerateRequest(prompt="hello")
+    return make_llm_generate_request(body)
+"""
+
+    assert _run(src, filename="src/sentry/seer/endpoints/issue_view_title_generate.py") == []
+
+
+def test_S030_rejects_new_legacy_caller() -> None:
+    src = """\
+from sentry.seer.signed_seer_api import LlmGenerateRequest, make_llm_generate_request
+
+
+def new_caller():
+    body = LlmGenerateRequest(prompt="hello")
+    return make_llm_generate_request(body)
+"""
+
+    errors = _run(src, filename="src/sentry/seer/new_caller.py")
+    assert len(errors) == 4
+    assert all("S030 Do not add new callers" in error for error in errors)
+
+
+def test_S030_rejects_second_call_in_allowlisted_function() -> None:
+    src = """\
+from sentry.seer.signed_seer_api import LlmGenerateRequest, make_llm_generate_request
+
+
+def generate_title_from_query():
+    first = LlmGenerateRequest(prompt="first")
+    second = LlmGenerateRequest(prompt="second")
+    make_llm_generate_request(first)
+    return make_llm_generate_request(second)
+"""
+
+    errors = _run(src, filename="src/sentry/seer/endpoints/issue_view_title_generate.py")
+    assert errors == [
+        "t.py:6:13: S030 Do not add new callers of the legacy Seer LLM generate API; "
+        "add a named Seer one-shot so prompts and model selection stay in Seer",
+        "t.py:8:11: S030 Do not add new callers of the legacy Seer LLM generate API; "
+        "add a named Seer one-shot so prompts and model selection stay in Seer",
+    ]
+
+
+def test_S030_rejects_aliased_and_module_qualified_calls() -> None:
+    aliased = """\
+from sentry.seer.signed_seer_api import LlmGenerateRequest as LegacyRequest
+
+LegacyRequest(prompt="hello")
+"""
+    module_qualified = """\
+import sentry.seer.signed_seer_api as seer_api
+
+seer_api.make_llm_generate_request({})
+"""
+
+    assert len(_run(aliased, filename="src/sentry/example.py")) == 2
+    assert len(_run(module_qualified, filename="src/sentry/example.py")) == 2
+
+
+def test_S030_rejects_direct_route_bypass() -> None:
+    src = 'make_signed_seer_api_request(pool, "/v1/llm/generate", b"{}")\n'
+
+    assert _run(src, filename="src/sentry/example.py") == [
+        "t.py:1:35: S030 Do not add new callers of the legacy Seer LLM generate API; "
+        "add a named Seer one-shot so prompts and model selection stay in Seer"
+    ]
+
+
+def test_S030_reports_stale_allowlist_entry() -> None:
+    src = """\
+from sentry.seer.signed_seer_api import LlmGenerateRequest, make_llm_generate_request
+
+
+def generate_title_from_query():
+    return None
+"""
+
+    errors = _run(src, filename="src/sentry/seer/endpoints/issue_view_title_generate.py")
+    assert len(errors) == 2
+    assert all("S030 stale legacy Seer LLM generate allowlist entry" in error for error in errors)
+
+
+def test_S030_allows_legacy_api_definition() -> None:
+    src = """\
+class LlmGenerateRequest: ...
+
+def make_llm_generate_request(body):
+    return make_signed_seer_api_request(pool, "/v1/llm/generate", body)
+"""
+
+    assert _run(src, filename="src/sentry/seer/signed_seer_api.py") == []
+
+
 def _codes(src: str) -> list[str]:
     """`line:CODE` for each diagnostic, for terse assertions."""
     tree = ast.parse(src)
 
@@ -2,6 +2,7 @@
 
 import ast
 import os
+from collections import Counter
 from collections.abc import Generator
 from datetime import datetime, timezone
 from typing import Any
@@ -164,6 +165,48 @@
     "raw urlopen bypasses ViewerContext propagation"
 )
 
+S030_msg = (
+    "S030 Do not add new callers of the legacy Seer LLM generate API; "
+    "add a named Seer one-shot so prompts and model selection stay in Seer"
+)
+S030_stale_msg = (
+    "S030 stale legacy Seer LLM generate allowlist entry for {} in {}; "
+    "remove it from S030_allowlist"
+)
+_S030_LEGACY_MODULE = "sentry.seer.signed_seer_api"
+_S030_LEGACY_NAMES = frozenset(("LlmGenerateRequest", "make_llm_generate_request"))
+_S030_LEGACY_ROUTE = "/v1/llm/generate"
+_S030_MODULE_SCOPE = "<module>"
+
+# Existing callers are pinned to their exact function and occurrence count. This is a
+# shrink-only migration baseline: remove entries as callers move to named Seer one-shots.
+S030_allowlist: dict[str, dict[tuple[str, str], int]] = {
+    "src/sentry/integrations/utils/external_issues.py": {
+        (_S030_MODULE_SCOPE, "import LlmGenerateRequest"): 1,
+        (_S030_MODULE_SCOPE, "import make_llm_generate_request"): 1,
+        ("_make_generate_external_issue_details_request", "call LlmGenerateRequest"): 1,
+        ("_make_generate_external_issue_details_request", "call make_llm_generate_request"): 1,
+    },
+    "src/sentry/seer/endpoints/issue_view_title_generate.py": {
+        (_S030_MODULE_SCOPE, "import LlmGenerateRequest"): 1,
+        (_S030_MODULE_SCOPE, "import make_llm_generate_request"): 1,
+        ("generate_title_from_query", "call LlmGenerateRequest"): 1,
+        ("generate_title_from_query", "call make_llm_generate_request"): 1,
+    },
+    "src/sentry/tasks/seer/autofix_issue_data.py": {
+        (_S030_MODULE_SCOPE, "import LlmGenerateRequest"): 1,
+        (_S030_MODULE_SCOPE, "import make_llm_generate_request"): 1,
+        ("_judge_issue", "call LlmGenerateRequest"): 1,
+        ("_judge_issue", "call make_llm_generate_request"): 1,
+    },
+    "src/sentry/uptime/seer_assertions.py": {
+        (_S030_MODULE_SCOPE, "import LlmGenerateRequest"): 1,
+        (_S030_MODULE_SCOPE, "import make_llm_generate_request"): 1,
+        ("generate_assertion_suggestions", "call LlmGenerateRequest"): 1,
+        ("generate_assertion_suggestions", "call make_llm_generate_request"): 1,
+    },
+}
+
 
 # Rules whose diagnostics are fatal. Empty ships every rule off; adding one
 # gates every endpoint of that shape at once, with no baseline to maintain.
@@ -715,6 +758,10 @@ def __init__(
         # S029: pools created from SEER_*_URL must not make raw requests.
         self._s029_seer_pool_names: set[str] = set()
         self._s029_urlopen_calls: list[tuple[int, int, str]] = []
+        # S030: legacy generic Seer LLM API imports, calls, and route bypasses.
+        self._s030_legacy_names: dict[str, str] = {}
+        self._s030_module_aliases: set[str] = set()
+        self._s030_uses: list[tuple[int, int, str, str]] = []
         # Module-level classes, indexed as encountered. A base is always defined
         # before its subclass at module level, so in-order indexing suffices.
         self._module_classes: dict[str, ast.ClassDef] = {}
@@ -727,6 +774,13 @@ def __init__(
         self._function_stack: list[str] = []
 
     def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
+        if node.module == _S030_LEGACY_MODULE and not node.level:
+            for alias in node.names:
+                if alias.name in _S030_LEGACY_NAMES:
+                    local_name = alias.asname or alias.name
+                    self._s030_legacy_names[local_name] = alias.name
+                    self._s030_record(node, f"import {alias.name}")
+
         if node.module and not node.level:
             if node.module.split(".")[0] in S003_modules:
                 self.errors.append((node.lineno, node.col_offset, S003_msg))
@@ -776,6 +830,10 @@ def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
 
     def visit_Import(self, node: ast.Import) -> None:
         for alias in node.names:
+            if alias.name == _S030_LEGACY_MODULE:
+                if alias.asname:
+                    self._s030_module_aliases.add(alias.asname)
+                self._s030_record(node, f"import {alias.name}")
             if alias.name.split(".")[0] in S003_modules:
                 self.errors.append((node.lineno, node.col_offset, S003_msg))
             elif (
@@ -818,6 +876,8 @@ def visit_Name(self, node: ast.Name) -> None:
     def visit_Constant(self, node: ast.Constant) -> None:
         if isinstance(node.value, str) and node.value == S018_fqn:
             self.errors.append((node.lineno, node.col_offset, S018_msg))
+        elif isinstance(node.value, str) and node.value == _S030_LEGACY_ROUTE:
+            self._s030_record(node, f"use {_S030_LEGACY_ROUTE}")
 
         self.generic_visit(node)
 
@@ -1032,6 +1092,22 @@ def _s024_visit_call(self, node: ast.Call) -> None:
             if self._s024_parses is None:
                 self._s024_parses = (node.lineno, node.col_offset)
 
+    def _s030_record(self, node: ast.stmt | ast.expr, kind: str) -> None:
+        function = self._function_stack[-1] if self._function_stack else _S030_MODULE_SCOPE
+        self._s030_uses.append((node.lineno, node.col_offset, function, kind))
+
+    def _s030_call_name(self, node: ast.expr) -> str | None:
+        if isinstance(node, ast.Name):
+            return self._s030_legacy_names.get(node.id)
+
+        qualified = _name_of(node)
+        for legacy_name in _S030_LEGACY_NAMES:
+            if qualified == f"{_S030_LEGACY_MODULE}.{legacy_name}":
+                return legacy_name
+            if any(qualified == f"{alias}.{legacy_name}" for alias in self._s030_module_aliases):
+                return legacy_name
+        return None
+
     def visit_Subscript(self, node: ast.Subscript) -> None:
         # Load only: `request.data["title"] = ...` writes a value, it does not
         # read a parameter the client sent.
@@ -1120,6 +1196,8 @@ def _exit_input(self) -> None:
 
     def visit_Call(self, node: ast.Call) -> None:
         self._s024_visit_call(node)
+        if legacy_name := self._s030_call_name(node.func):
+            self._s030_record(node, f"call {legacy_name}")
         if isinstance(node.func, ast.Attribute) and node.func.attr == "urlopen":
             self._s029_urlopen_calls.append(
                 (node.lineno, node.col_offset, _name_of(node.func.value))
@@ -1201,6 +1279,7 @@ def run(self) -> Generator[tuple[int, int, str, type[Any]]]:
 
         yield from self._s024(visitor)
         yield from self._s029(visitor)
+        yield from self._s030(visitor)
 
         for e in visitor.errors:
             yield (*e, type(self))
@@ -1221,3 +1300,21 @@ def _s029(self, visitor: SentryVisitor) -> Generator[tuple[int, int, str, type[A
         for line, col, receiver in visitor._s029_urlopen_calls:
             if receiver in visitor._s029_seer_pool_names:
                 yield (line, col, S029_msg, type(self))
+
+    def _s030(self, visitor: SentryVisitor) -> Generator[tuple[int, int, str, type[Any]]]:
+        rel = _repo_relative(self.filename)
+        if not rel.startswith("src/sentry/") or rel == "src/sentry/seer/signed_seer_api.py":
+            return
+
+        allowed = S030_allowlist.get(rel, {})
+        seen: Counter[tuple[str, str]] = Counter()
+        for line, col, function, kind in visitor._s030_uses:
+            key = (function, kind)
+            seen[key] += 1
+            if seen[key] > allowed.get(key, 0):
+                yield (line, col, S030_msg, type(self))
+
+        for key, expected_count in allowed.items():
+            if seen[key] < expected_count:
+                function, kind = key
+                yield (1, 0, S030_stale_msg.format(kind, function), type(self))