Centralize GPT-5 temperature override into llmutils.ResolveTemperature

Eliminates identical temperature resolution logic duplicated in
hexaiaction, hexaicli, and lsp packages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/internal/llmutils/temperature.go b/internal/llmutils/temperature.go
new file mode 100644
index 0000000..8e10c66
--- /dev/null
+++ b/internal/llmutils/temperature.go
@@ -0,0 +1,37 @@
+// Package llmutils provides shared utilities for LLM configuration.
+// ResolveTemperature centralizes the GPT-5 temperature override logic
+// that was previously duplicated across hexaiaction, hexaicli, and lsp.
+package llmutils
+
+import "strings"
+
+// isGPT5 returns true when the model name indicates an OpenAI GPT-5 variant.
+func isGPT5(provider, model string) bool {
+	return provider == "openai" &&
+		strings.HasPrefix(strings.ToLower(model), "gpt-5")
+}
+
+// ResolveTemperature picks the effective temperature from an optional
+// per-surface override (entryTemp) or the global coding temperature
+// (codingTemp). For OpenAI GPT-5 models the default coding temperature
+// of 0.2 is automatically raised to 1.0, and when no temperature is
+// configured at all GPT-5 defaults to 1.0.
+//
+// Returns (temperature, true) when a value was resolved, or (0, false)
+// when no temperature should be sent (let the provider choose).
+func ResolveTemperature(provider, model string, entryTemp, codingTemp *float64) (float64, bool) {
+	if entryTemp != nil {
+		return *entryTemp, true
+	}
+	if codingTemp != nil {
+		temp := *codingTemp
+		if isGPT5(provider, model) && temp == 0.2 {
+			temp = 1.0
+		}
+		return temp, true
+	}
+	if isGPT5(provider, model) {
+		return 1.0, true
+	}
+	return 0, false
+}