diff --git a/CHANGELOG.md b/CHANGELOG.md
index b47e30d..be74101 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,15 @@
 All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/).
 
+## [Unreleased]
+
+### Changed
+
+- Default OpenAI model for `decompose` / `recompose` generation is now `gpt-5.4`
+  (was `gpt-4.1`). Validated as the strong, low-cost default in the staging
+  repair-loop benchmarks; fully overridable via `--model`. Review/specialist
+  models and the benchmark baseline are unchanged.
+
 ## [1.0.1] - 2026-05-08
 
 ### Added
diff --git a/cli/pipeline/decompose_v2.py b/cli/pipeline/decompose_v2.py
index 78b1c56..0c1ad43 100644
--- a/cli/pipeline/decompose_v2.py
+++ b/cli/pipeline/decompose_v2.py
@@ -14,7 +14,7 @@
 import anthropic
 
 MODEL = "claude-sonnet-4-5"
-DEFAULT_OPENAI_MODEL = "gpt-4.1"
+DEFAULT_OPENAI_MODEL = "gpt-5.4"  # was gpt-4.1; gpt-5* params handled via is_reasoning. Override: --model
 
 
 def _call_anthropic(client, *, tool, system, user, temperature):
diff --git a/cli/pipeline/recompose_v2.py b/cli/pipeline/recompose_v2.py
index 2ae7338..ad175e7 100644
--- a/cli/pipeline/recompose_v2.py
+++ b/cli/pipeline/recompose_v2.py
@@ -19,7 +19,7 @@
 import httpx
 
 MODEL = "claude-sonnet-4-5"
-DEFAULT_OPENAI_MODEL = "gpt-4.1"
+DEFAULT_OPENAI_MODEL = "gpt-5.4"  # was gpt-4.1; gpt-5* params handled via is_reasoning. Override: --model
 
 CODE_TOOL = {
     "name": "emit_code",