diff --git a/README.md b/README.md
index 384561c..0af81be 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ Consilium queries multiple LLMs in parallel, has each model review the others' r
 │                    STAGE 1: QUERY                       │
 │                                                         │
 │   ┌─────────┐   ┌──────────┐   ┌─────────────────┐     │
-│   │ GPT-5.2 │   │ Claude   │   │ Gemini 3.1 Pro  │     │
+│   │ GPT-5.4 │   │ Claude   │   │ Gemini 3.1 Pro  │     │
 │   │         │   │ Sonnet   │   │                 │     │
 │   └────┬────┘   └────┬─────┘   └────────┬────────┘     │
 │        │             │                  │               │
@@ -90,7 +90,7 @@ The main orchestrator class.
 from consilium import Council
 
 council = Council(
-    models=["gpt-5.2", "claude-sonnet-4-6", "gemini-3.1-pro"],
+    models=["gpt-5.4", "claude-sonnet-4-6", "gemini-3.1-pro"],
     chairman="claude-sonnet-4-6",
     max_workers=8,
 )
@@ -100,7 +100,7 @@ council = Council(
 
 | Parameter | Type | Default | Description |
 |-----------|------|---------|-------------|
-| `models` | `list[str]` | `["gpt-5.2", "claude-sonnet-4-6", "gemini-3.1-pro"]` | Models to query in Stage 1 |
+| `models` | `list[str]` | `["gpt-5.4", "claude-sonnet-4-6", "gemini-3.1-pro"]` | Models to query in Stage 1 |
 | `chairman` | `str` | `"claude-sonnet-4-6"` | Model for Stage 3 synthesis |
 | `max_workers` | `int` | `8` | Max parallel threads |
 
@@ -138,7 +138,7 @@ from consilium import council_query
 result = council_query(
     "Analyze this screenshot and list the UI elements",
     images=[screenshot_bytes],
-    models=["gpt-5.2", "claude-sonnet-4-6"],
+    models=["gpt-5.4", "claude-sonnet-4-6"],
     budget=0.25,
     skip_review=True,  # fast mode: Stage 1 only
 )
@@ -154,7 +154,7 @@ print(result["cost"]["total_usd"])
   "final_answer": "...",
   "individual_responses": [
     {
-      "model": "openai/gpt-5.2",
+      "model": "openai/gpt-5.4",
       "text": "...",
       "latency_seconds": 2.1,
       "input_tokens": 1500,
@@ -164,7 +164,7 @@ print(result["cost"]["total_usd"])
   ],
   "reviews": [...],
   "cost": {
-    "breakdown": {"gpt-5.2": 0.007, "claude-sonnet-4-6": 0.012},
+    "breakdown": {"gpt-5.4": 0.007, "claude-sonnet-4-6": 0.012},
     "total_usd": 0.019,
     "total_input_tokens": 3000,
     "total_output_tokens": 800
@@ -179,7 +179,7 @@ print(result["cost"]["total_usd"])
 consilium "prompt" [OPTIONS]
 
 Options:
-  --models TEXT      Comma-separated model IDs (default: gpt-5.2,claude-sonnet-4-6,gemini-3.1-pro)
+  --models TEXT      Comma-separated model IDs (default: gpt-5.4,claude-sonnet-4-6,gemini-3.1-pro)
   --chairman TEXT    Chairman model for synthesis (default: claude-sonnet-4-6)
   --image PATH      Image file to include (repeatable)
   --budget FLOAT    Max spend in USD
@@ -207,7 +207,7 @@ consilium "Write a haiku about AI" --budget 0.10
 consilium "List 3 colors" --json | jq '.final_answer'
 
 # Custom models
-consilium "Hello" --models gpt-5.2,gemini-3.1-pro --chairman gpt-5.2
+consilium "Hello" --models gpt-5.4,gemini-3.1-pro --chairman gpt-5.4
 ```
 
 ## Model Support
@@ -216,14 +216,14 @@ Consilium supports any model from these providers:
 
 | Provider | Models | Env Var |
 |----------|--------|---------|
-| OpenAI | `gpt-5.2`, `gpt-5.2-pro`, `gpt-5`, `gpt-5-mini`, `o3`, `o4-mini` | `OPENAI_API_KEY` |
+| OpenAI | `gpt-5.4`, `gpt-5.4-pro`, `gpt-5`, `gpt-5-mini`, `o3`, `o4-mini` | `OPENAI_API_KEY` |
 | Anthropic | `claude-opus-4-6`, `claude-sonnet-4-6`, `claude-haiku-4-5`, `claude-sonnet-4-5` | `ANTHROPIC_API_KEY` |
 | Google | `gemini-3.1-pro`, `gemini-3-flash`, `gemini-2.5-pro`, `gemini-2.5-flash` | `GOOGLE_API_KEY` |
 
 Use any model with the `provider/model` format:
 
 ```python
-council = Council(models=["openai/gpt-5.2", "anthropic/claude-sonnet-4-6"])
+council = Council(models=["openai/gpt-5.4", "anthropic/claude-sonnet-4-6"])
 ```
 
 ## Budget Control
diff --git a/src/consilium/__main__.py b/src/consilium/__main__.py
index ff48bfb..2e7e85f 100644
--- a/src/consilium/__main__.py
+++ b/src/consilium/__main__.py
@@ -4,7 +4,7 @@
 
     consilium "What color is the sky?"
     consilium "Describe this screenshot" --image screenshot.png
-    consilium "Hello" --models gpt-5.2,claude-sonnet-4-6 --no-review
+    consilium "Hello" --models gpt-5.4,claude-sonnet-4-6 --no-review
     consilium "Plan a trip" --budget 0.50
     consilium "Compare approaches" --json
 """
diff --git a/src/consilium/cost.py b/src/consilium/cost.py
index 3adcc5a..a582a47 100644
--- a/src/consilium/cost.py
+++ b/src/consilium/cost.py
@@ -28,6 +28,7 @@
     "gemini-2.5-flash": (0.15, 0.60),
     "gemini-2.5-pro": (1.25, 10.0),
     # OpenAI — GPT-5.x series (current)
+    "gpt-5.4": (2.0, 8.0),
     "gpt-5.2": (2.0, 8.0),
     "gpt-5.2-pro": (10.0, 40.0),
     "gpt-5": (2.0, 8.0),
diff --git a/src/consilium/model_registry.py b/src/consilium/model_registry.py
index 0d0d3fb..a50faae 100644
--- a/src/consilium/model_registry.py
+++ b/src/consilium/model_registry.py
@@ -49,7 +49,7 @@ def __post_init__(self) -> None:
 
 DEFAULTS: Dict[str, Dict[str, str]] = {
     "openai": {
-        "flagship": "gpt-5.2",
+        "flagship": "gpt-5.4",
         "fast": "gpt-5-mini",
         "reasoning": "o3",
         "reasoning_fast": "o4-mini",