diff --git a/agent-client/pi/extensions/iop-read-limit.ts b/agent-client/pi/extensions/iop-read-limit.ts
new file mode 100644
index 00000000..b519d8a2
--- /dev/null
+++ b/agent-client/pi/extensions/iop-read-limit.ts
@@ -0,0 +1,13 @@
+import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+
+const IOP_MAX_READ_LINES = 240;
+
+export default function (pi: ExtensionAPI) {
+	pi.on("tool_call", (event, ctx) => {
+		if (ctx.model?.provider !== "iop" || event.toolName !== "read") return;
+		const limit = event.input.limit;
+		if (typeof limit !== "number" || limit > IOP_MAX_READ_LINES) {
+			event.input.limit = IOP_MAX_READ_LINES;
+		}
+	});
+}
diff --git a/agent-client/pi/install.sh b/agent-client/pi/install.sh
index dbb2f941..86981e5d 100755
--- a/agent-client/pi/install.sh
+++ b/agent-client/pi/install.sh
@@ -4,6 +4,7 @@ set -euo pipefail
 PI_DIR="$HOME/.pi/agent"
 SETTINGS="$PI_DIR/settings.json"
 MODELS="$PI_DIR/models.json"
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 PYTHON_BIN="/usr/bin/python3"
 
 if [[ ! -x "$PYTHON_BIN" ]]; then
@@ -16,6 +17,8 @@ if [[ -z "$PYTHON_BIN" || ! -x "$PYTHON_BIN" ]]; then
 fi
 
 mkdir -p "$PI_DIR"
+mkdir -p "$PI_DIR/extensions"
+install -m 0644 "$SCRIPT_DIR/extensions/iop-read-limit.ts" "$PI_DIR/extensions/iop-read-limit.ts"
 
 "$PYTHON_BIN" - "$SETTINGS" "$MODELS" <<'PY'
 import json
diff --git a/agent-client/pi/install_test.py b/agent-client/pi/install_test.py
index ae34db6c..fc058239 100644
--- a/agent-client/pi/install_test.py
+++ b/agent-client/pi/install_test.py
@@ -55,6 +55,7 @@ class _TempHomeMixin:
         self.pi_dir.mkdir(parents=True)
         self.settings_path = self.pi_dir / "settings.json"
         self.models_path = self.pi_dir / "models.json"
+        self.read_limit_path = self.pi_dir / "extensions" / "iop-read-limit.ts"
 
     def tearDown(self):
         shutil.rmtree(self.tmp_home, ignore_errors=True)
@@ -192,6 +193,7 @@ class TestPreservesOpenaiResponsesConsumptionAndUserSettings(_TempHomeMixin, uni
         #      (already checked above but be explicit about the contract)
         legacy_in_enabled = [m for m in enabled if m.startswith("seulgivibe-openai/")]
         self.assertEqual(legacy_in_enabled, [], "Legacy openai entries must be removed from enabledModels")
+        self.assertIn("IOP_MAX_READ_LINES = 240", self.read_limit_path.read_text())
 
 
 class TestIdempotentRerun(_TempHomeMixin, unittest.TestCase):