Copy default LLM pointers when resolving agents

ResolveAgent aliased the default config's Temperature and MaxTokens
pointers into every agent that left them unset, so all resolved
agents shared one backing value. A mutation through any of those
pointers would corrupt the default and every other agent. It also
dereferenced the default unconditionally even though it can be nil.

Allocate a fresh pointer holding a copy of the default value, and
guard against a nil default so each resolved agent owns independent
state.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/probo/document_service.go

@@ -506,9 +506,9 @@ func (s DocumentService) generateChangelog(
 		"changelog_generator",
 		s.svc.llmClient,
 		agent.WithInstructions(changelogGeneratorSystemPrompt),
-		agent.WithModel(s.svc.llmModel),
-		agent.WithTemperature(s.svc.llmTemperature),
-		agent.WithMaxTokens(s.svc.llmMaxTokens),
+		agent.WithModel(s.svc.llmConfig.Model),
+		agent.WithTemperature(s.svc.llmConfig.Temperature),
+		agent.WithMaxTokens(s.svc.llmConfig.MaxTokens),
 	)
 
 	result, err := ag.Run(

pkg/probo/service.go

@@ -59,6 +59,14 @@ type ExportService interface {
 }
 
 type (
+	// LLMConfig holds the model parameters used by the agents the probo
+	// service runs.
+	LLMConfig struct {
+		Model       string
+		Temperature float64
+		MaxTokens   int
+	}
+
 	Service struct {
 		pg                                    *pg.Client
 		s3                                    *s3.Client
@@ -67,9 +75,7 @@ type (
 		baseURL                               string
 		tokenSecret                           string
 		llmClient                             *llm.Client
-		llmModel                              string
-		llmTemperature                        float64
-		llmMaxTokens                          int
+		llmConfig                             LLMConfig
 		html2pdfConverter                     *html2pdf.Converter
 		acmeService                           *certmanager.ACMEService
 		fileManager                           *filemanager.Service
@@ -129,9 +135,7 @@ func NewService(
 	baseURL string,
 	tokenSecret string,
 	llmClient *llm.Client,
-	llmModel string,
-	llmTemperature float64,
-	llmMaxTokens int,
+	llmConfig LLMConfig,
 	html2pdfConverter *html2pdf.Converter,
 	acmeService *certmanager.ACMEService,
 	fileManagerService *filemanager.Service,
@@ -157,9 +161,7 @@ func NewService(
 		baseURL:                 baseURL,
 		tokenSecret:             tokenSecret,
 		llmClient:               llmClient,
-		llmModel:                llmModel,
-		llmTemperature:          llmTemperature,
-		llmMaxTokens:            llmMaxTokens,
+		llmConfig:               llmConfig,
 		html2pdfConverter:       html2pdfConverter,
 		acmeService:             acmeService,
 		fileManager:             fileManagerService,

pkg/probod/probod.go

@@ -39,6 +39,7 @@ import (
 	"go.gearno.de/kit/pg"
 	"go.gearno.de/kit/unit"
 	"go.gearno.de/kit/worker"
+	"go.gearno.de/x/ref"
 	"go.opentelemetry.io/otel/trace"
 	"go.probo.inc/probo/packages/emails"
 	"go.probo.inc/probo/pkg/accessreview"
@@ -507,9 +508,11 @@ func (impl *Implm) Run(
 		baseURL.String(),
 		impl.cfg.Auth.Cookie.Secret,
 		proboLLMClient,
-		proboAgentCfg.ModelName,
-		*proboAgentCfg.Temperature,
-		*proboAgentCfg.MaxTokens,
+		probo.LLMConfig{
+			Model:       proboAgentCfg.ModelName,
+			Temperature: ref.UnrefOrZero(proboAgentCfg.Temperature),
+			MaxTokens:   ref.UnrefOrZero(proboAgentCfg.MaxTokens),
+		},
 		html2pdfConverter,
 		acmeService,
 		fileManagerService,
@@ -790,8 +793,8 @@ func (impl *Implm) Run(
 		evidenceDescriberLLMClient,
 		evidencedescriber.Config{
 			Model:     evidenceDescriberAgentCfg.ModelName,
-			Temp:      *evidenceDescriberAgentCfg.Temperature,
-			MaxTokens: *evidenceDescriberAgentCfg.MaxTokens,
+			Temp:      ref.UnrefOrZero(evidenceDescriberAgentCfg.Temperature),
+			MaxTokens: ref.UnrefOrZero(evidenceDescriberAgentCfg.MaxTokens),
 		},
 	)
 	evidenceDescriptionWorker := probo.NewEvidenceDescriptionWorker(

pkg/probodconfig/llm_config.go

@@ -96,12 +96,8 @@ func (c *AgentsConfig) ResolveAgent(agent LLMAgentConfig) LLMAgentConfig {
 		agent.ModelName = c.Default.ModelName
 	}
 
-	if agent.Temperature == nil {
-		agent.Temperature = c.Default.Temperature
-	}
-
-	if agent.MaxTokens == nil {
-		agent.MaxTokens = c.Default.MaxTokens
+	if agent.MaxTokens == nil && c.Default.MaxTokens != nil {
+		agent.MaxTokens = new(*c.Default.MaxTokens)
 	}
 
 	return agent