diff --git a/README.md b/README.md
index 652792d83..61cd03abf 100644
--- a/README.md
+++ b/README.md
@@ -274,6 +274,7 @@ picoclaw onboard
       "workspace": "~/.picoclaw/workspace",
       "model_name": "gpt-5.4",
       "max_tokens": 8192,
+      "context_window": 131072,
       "temperature": 0.7,
       "max_tool_iterations": 20
     }
@@ -1019,6 +1020,7 @@ picoclaw onboard
       "workspace": "~/.picoclaw/workspace",
       "model_name": "gpt-5.4",
       "max_tokens": 8192,
+      "context_window": 131072,
       "temperature": 0.7,
       "max_tool_iterations": 20
     }
@@ -1492,7 +1494,7 @@ User Groups:
 
 discord: <https://discord.gg/V4sAZ9XWpN>
 
-<img src="assets/wechat.png" alt="PicoClaw" width="512">
+<img src="assets/wechat.png" alt="PicoClaw" width="512">
 
 ## <img src="assets/clawdchat-icon.png" width="24" height="24" alt="ClawdChat"> Join the Agent Social Network
 
diff --git a/config/config.example.json b/config/config.example.json
index 81c9014ec..9c584042e 100644
--- a/config/config.example.json
+++ b/config/config.example.json
@@ -5,6 +5,7 @@
       "restrict_to_workspace": true,
       "model_name": "gpt-5.4",
       "max_tokens": 8192,
+      "context_window": 131072,
       "temperature": 0.7,
       "max_tool_iterations": 20,
       "summarize_message_threshold": 20,
diff --git a/docs/docker.md b/docs/docker.md
index f868d4a42..3ffd01ba0 100644
--- a/docs/docker.md
+++ b/docs/docker.md
@@ -84,6 +84,7 @@ picoclaw onboard
       "workspace": "~/.picoclaw/workspace",
       "model_name": "gpt-5.4",
       "max_tokens": 8192,
+      "context_window": 131072,
       "temperature": 0.7,
       "max_tool_iterations": 20
     }
diff --git a/docs/providers.md b/docs/providers.md
index dde1814fb..5a806947d 100644
--- a/docs/providers.md
+++ b/docs/providers.md
@@ -95,7 +95,9 @@ This design also enables **multi-agent support** with flexible provider selectio
   ],
   "agents": {
     "defaults": {
-      "model_name": "gpt-5.4"
+      "model_name": "gpt-5.4",
+      "max_tokens": 8192,
+      "context_window": 131072
     }
   }
 }
diff --git a/pkg/agent/instance.go b/pkg/agent/instance.go
index 355e78a33..5e4086f41 100644
--- a/pkg/agent/instance.go
+++ b/pkg/agent/instance.go
@@ -130,6 +130,12 @@ func NewAgentInstance(
 		maxTokens = 8192
 	}
 
+	// Resolve context window: use context_window if set, otherwise fall back to max_tokens
+	contextWindow := defaults.ContextWindow
+	if contextWindow == 0 {
+		contextWindow = maxTokens
+	}
+
 	temperature := 0.7
 	if defaults.Temperature != nil {
 		temperature = *defaults.Temperature
@@ -182,7 +188,7 @@ func NewAgentInstance(
 		MaxTokens:                 maxTokens,
 		Temperature:               temperature,
 		ThinkingLevel:             thinkingLevel,
-		ContextWindow:             maxTokens,
+		ContextWindow:             contextWindow,
 		SummarizeMessageThreshold: summarizeMessageThreshold,
 		SummarizeTokenPercent:     summarizeTokenPercent,
 		Provider:                  provider,
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 235cb0641..c421d02e8 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -238,6 +238,7 @@ type AgentDefaults struct {
 	ImageModel                string             `json:"image_model,omitempty"           env:"PICOCLAW_AGENTS_DEFAULTS_IMAGE_MODEL"`
 	ImageModelFallbacks       []string           `json:"image_model_fallbacks,omitempty"`
 	MaxTokens                 int                `json:"max_tokens"                      env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOKENS"`
+	ContextWindow             int                `json:"context_window"                 env:"PICOCLAW_AGENTS_DEFAULTS_CONTEXT_WINDOW"`
 	Temperature               *float64           `json:"temperature,omitempty"           env:"PICOCLAW_AGENTS_DEFAULTS_TEMPERATURE"`
 	MaxToolIterations         int                `json:"max_tool_iterations"             env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOOL_ITERATIONS"`
 	SummarizeMessageThreshold int                `json:"summarize_message_threshold"     env:"PICOCLAW_AGENTS_DEFAULTS_SUMMARIZE_MESSAGE_THRESHOLD"`
diff --git a/pkg/config/defaults.go b/pkg/config/defaults.go
index 0d2141ae1..777ef312c 100644
--- a/pkg/config/defaults.go
+++ b/pkg/config/defaults.go
@@ -31,6 +31,7 @@ func DefaultConfig() *Config {
 				Provider:                  "",
 				Model:                     "",
 				MaxTokens:                 32768,
+				ContextWindow:             131072,
 				Temperature:               nil, // nil means use provider default
 				MaxToolIterations:         50,
 				SummarizeMessageThreshold: 20,