fix(api-server): correct test assertions, symmetric sentinel for max_tokens

Fix TestAgentPostLlmDefaults to assert 0.7/4000 (the actual defaults
applied by BeforeCreate), not 0.0/0. Add unsetMaxTokens sentinel (-1)
mirroring the temperature approach so POST max_tokens=0 behaves the
same as POST temperature=0 — both preserve explicit zero via PATCH
while applying defaults on omitted POST.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jsell-rh

components/ambient-api-server/plugins/agents/integration_test.go

@@ -145,9 +145,9 @@ func TestAgentPostLlmDefaults(t *testing.T) {
 	Expect(agentOutput.LlmModel).NotTo(BeNil(), "llm_model should be defaulted")
 	Expect(*agentOutput.LlmModel).To(Equal("claude-sonnet-4-6"))
 	Expect(agentOutput.LlmTemperature).NotTo(BeNil(), "llm_temperature should be present")
-	Expect(*agentOutput.LlmTemperature).To(BeNumerically("~", 0.0, 0.001))
+	Expect(*agentOutput.LlmTemperature).To(BeNumerically("~", 0.7, 0.001))
 	Expect(agentOutput.LlmMaxTokens).NotTo(BeNil(), "llm_max_tokens should be present")
-	Expect(*agentOutput.LlmMaxTokens).To(Equal(int32(0)))
+	Expect(*agentOutput.LlmMaxTokens).To(Equal(int32(4000)))
 }
 
 func TestAgentPatch(t *testing.T) {

components/ambient-api-server/plugins/agents/model.go

@@ -38,9 +38,13 @@ func (l AgentList) Index() AgentIndex {
 	return index
 }
 
-// unsetTemperature is a sentinel value indicating the caller did not provide a temperature.
-// Valid temperatures are 0.0–2.0, so -1 is unambiguously "unset".
-const unsetTemperature = -1.0
+// Sentinel values indicating the caller did not provide a value.
+// Valid temperatures are 0.0–2.0 and valid max_tokens are > 0,
+// so negative values are unambiguously "unset".
+const (
+	unsetTemperature float64 = -1.0
+	unsetMaxTokens   int32   = -1
+)
 
 func (d *Agent) BeforeCreate(tx *gorm.DB) error {
 	d.ID = api.NewID()
@@ -50,7 +54,7 @@ func (d *Agent) BeforeCreate(tx *gorm.DB) error {
 	if d.LlmTemperature == unsetTemperature {
 		d.LlmTemperature = 0.7
 	}
-	if d.LlmMaxTokens <= 0 {
+	if d.LlmMaxTokens == unsetMaxTokens {
 		d.LlmMaxTokens = 4000
 	}
 	return nil

components/ambient-api-server/plugins/agents/presenter.go

@@ -32,6 +32,8 @@ func ConvertAgent(agent openapi.Agent) *Agent {
 	}
 	if agent.LlmMaxTokens != nil {
 		c.LlmMaxTokens = *agent.LlmMaxTokens
+	} else {
+		c.LlmMaxTokens = unsetMaxTokens
 	}
 	c.BotAccountName = agent.BotAccountName
 	c.ResourceOverrides = agent.ResourceOverrides