diff --git a/ui/src/adapters/claude-local/config-fields.tsx b/ui/src/adapters/claude-local/config-fields.tsx
index f7887279..b57024b6 100644
--- a/ui/src/adapters/claude-local/config-fields.tsx
+++ b/ui/src/adapters/claude-local/config-fields.tsx
@@ -10,8 +10,40 @@ import {
 const inputClass =
   "w-full rounded-md border border-border px-2.5 py-1.5 bg-transparent outline-none text-sm font-mono placeholder:text-muted-foreground/40";
 
-export function ClaudeLocalConfigFields(_props: AdapterConfigFieldsProps) {
-  return null;
+const instructionsFileHint =
+  "Absolute path to a markdown file (e.g. AGENTS.md) that defines this agent's behavior. Injected into the system prompt at runtime.";
+
+export function ClaudeLocalConfigFields({
+  isCreate,
+  values,
+  set,
+  config,
+  eff,
+  mark,
+}: AdapterConfigFieldsProps) {
+  return (
+    <Field label="Agent instructions file" hint={instructionsFileHint}>
+      <DraftInput
+        value={
+          isCreate
+            ? values!.instructionsFilePath ?? ""
+            : eff(
+                "adapterConfig",
+                "instructionsFilePath",
+                String(config.instructionsFilePath ?? ""),
+              )
+        }
+        onCommit={(v) =>
+          isCreate
+            ? set!({ instructionsFilePath: v })
+            : mark("adapterConfig", "instructionsFilePath", v || undefined)
+        }
+        immediate
+        className={inputClass}
+        placeholder="/absolute/path/to/AGENTS.md"
+      />
+    </Field>
+  );
 }
 
 export function ClaudeLocalAdvancedFields({
diff --git a/ui/src/adapters/codex-local/config-fields.tsx b/ui/src/adapters/codex-local/config-fields.tsx
index 4de58c75..e487a7bc 100644
--- a/ui/src/adapters/codex-local/config-fields.tsx
+++ b/ui/src/adapters/codex-local/config-fields.tsx
@@ -1,9 +1,16 @@
 import type { AdapterConfigFieldsProps } from "../types";
 import {
+  Field,
   ToggleField,
+  DraftInput,
   help,
 } from "../../components/agent-config-primitives";
 
+const inputClass =
+  "w-full rounded-md border border-border px-2.5 py-1.5 bg-transparent outline-none text-sm font-mono placeholder:text-muted-foreground/40";
+const instructionsFileHint =
+  "Absolute path to a markdown file (e.g. AGENTS.md) that defines this agent's behavior. Injected into the system prompt at runtime.";
+
 export function CodexLocalConfigFields({
   isCreate,
   values,
@@ -17,6 +24,27 @@ export function CodexLocalConfigFields({
 
   return (
     <>
+      <Field label="Agent instructions file" hint={instructionsFileHint}>
+        <DraftInput
+          value={
+            isCreate
+              ? values!.instructionsFilePath ?? ""
+              : eff(
+                  "adapterConfig",
+                  "instructionsFilePath",
+                  String(config.instructionsFilePath ?? ""),
+                )
+          }
+          onCommit={(v) =>
+            isCreate
+              ? set!({ instructionsFilePath: v })
+              : mark("adapterConfig", "instructionsFilePath", v || undefined)
+          }
+          immediate
+          className={inputClass}
+          placeholder="/absolute/path/to/AGENTS.md"
+        />
+      </Field>
       <ToggleField
         label="Bypass sandbox"
         hint={help.dangerouslyBypassSandbox}
diff --git a/ui/src/components/agent-config-defaults.ts b/ui/src/components/agent-config-defaults.ts
index b94c23ea..3434f08d 100644
--- a/ui/src/components/agent-config-defaults.ts
+++ b/ui/src/components/agent-config-defaults.ts
@@ -3,6 +3,7 @@ import type { CreateConfigValues } from "@paperclip/adapter-utils";
 export const defaultCreateValues: CreateConfigValues = {
   adapterType: "claude_local",
   cwd: "",
+  instructionsFilePath: "",
   promptTemplate: "",
   model: "",
   thinkingEffort: "",