diff --git a/pkg/config/config.go b/pkg/config/config.go
index 305ae67e3..eeca9638e 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -180,6 +180,16 @@ type AgentDefaults struct {
 	MaxTokens                 int      `json:"max_tokens"                      env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOKENS"`
 	Temperature               *float64 `json:"temperature,omitempty"           env:"PICOCLAW_AGENTS_DEFAULTS_TEMPERATURE"`
 	MaxToolIterations         int      `json:"max_tool_iterations"             env:"PICOCLAW_AGENTS_DEFAULTS_MAX_TOOL_ITERATIONS"`
+	MaxMediaSize              int      `json:"max_media_size,omitempty"        env:"PICOCLAW_AGENTS_DEFAULTS_MAX_MEDIA_SIZE"`
+}
+
+const DefaultMaxMediaSize = 20 * 1024 * 1024 // 20 MB
+
+func (d *AgentDefaults) GetMaxMediaSize() int {
+	if d.MaxMediaSize > 0 {
+		return d.MaxMediaSize
+	}
+	return DefaultMaxMediaSize
 }
 
 // GetModelName returns the effective model name for the agent defaults.