Function ResolveChainMode

coderd/x/chatd/chatopenai/responses.go:206–240

ResolveChainMode scans DB messages from the end to inspect the current trailing user turn and detect whether the immediately preceding assistant/tool block can chain from a provider response ID.

(messages []database.ChatMessage)

// trailing user turn and detect whether the immediately preceding assistant/tool
// block can chain from a provider response ID.
func ResolveChainMode(messages []database.ChatMessage) ChainModeInfo {
	var info ChainModeInfo
	i := len(messages) - 1
	for ; i >= 0; i-- {
		if messages[i].Role != database.ChatMessageRoleUser {
			break
		}
		if userMessageContributesToChainMode(messages[i]) {
			info.contributingTrailingUserCount++
		}
	}
	for ; i >= 0; i-- {
		switch messages[i].Role {
		case database.ChatMessageRoleAssistant:
			if messages[i].ProviderResponseID.Valid &&
				messages[i].ProviderResponseID.String != "" {
				info.previousResponseID = messages[i].ProviderResponseID.String
				if messages[i].ModelConfigID.Valid {
					info.modelConfigID = messages[i].ModelConfigID.UUID
				}
				info.hasUnresolvedLocalToolCalls = assistantHasUnresolvedLocalToolCalls(messages, i)
				if !info.hasUnresolvedLocalToolCalls {
					info.providerMissingToolResults = providerHasMissingToolResults(messages, i)
				}
				return info
			}
			return info
		case database.ChatMessageRoleTool:
			continue
		default:
			return info
		}
	}
	return info
}

// FilterPromptForChainMode keeps only system messages and the trailing user
// messages that still contribute model-visible content to the current turn.