fix(agents): clear stale frontier tool denies

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/agents/frontier-tool-schema-guard.ts

@@ -1,4 +1,9 @@
+import type { AgentConfig } from "@opencode-ai/sdk"
 import { isGpt5_5Model } from "./types"
+import type { PermissionValue } from "../shared/permission-compat"
+
+const FRONTIER_TOOL_SCHEMA_NAMES = ["grep", "glob"] as const
+type MutablePermission = Record<string, PermissionValue | Record<string, PermissionValue>>
 
 function isOpus47Model(model: string): boolean {
   const modelName = model.includes("/") ? (model.split("/").pop() ?? model) : model
@@ -10,3 +15,25 @@ export function getFrontierToolSchemaPermission(model: string): Record<string, "
     ? { grep: "deny" as const, glob: "deny" as const }
     : {}
 }
+
+export function applyFrontierToolSchemaPermission(
+  permission: AgentConfig["permission"] | undefined,
+  model: string,
+  explicitPermission?: AgentConfig["permission"]
+): AgentConfig["permission"] | undefined {
+  if (!permission) return permission
+
+  const nextPermission: MutablePermission = { ...permission }
+  const explicitPermissionMap = explicitPermission as MutablePermission | undefined
+  const frontierDeny = getFrontierToolSchemaPermission(model)
+  if (Object.keys(frontierDeny).length > 0) {
+    Object.assign(nextPermission, frontierDeny)
+    return nextPermission as AgentConfig["permission"]
+  }
+
+  for (const toolName of FRONTIER_TOOL_SCHEMA_NAMES) {
+    if (explicitPermissionMap?.[toolName] === "deny") continue
+    delete nextPermission[toolName]
+  }
+  return nextPermission as AgentConfig["permission"]
+}