fix: address delegation client review feedback

Signed-off-by: Michael Kantor <6068672+kantorcodes@users.noreply.github.com>

Author: kantorcodes

examples/registry-broker-delegation/main.go

@@ -17,7 +17,8 @@ const (
 
 func main() {
 	if err := run(); err != nil {
-		fmt.Println("error:", err)
+		_, _ = fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
 	}
 }
 

examples/registry-broker-delegation/main_test.go

@@ -3,7 +3,25 @@ package main
 import "testing"
 
 func TestGetEnvOrDefault(t *testing.T) {
-	if value := getEnvOrDefault("REGISTRY_BROKER_DELEGATION_EXAMPLE_MISSING", "fallback"); value != "fallback" {
-		t.Fatalf("expected fallback, got %s", value)
-	}
+	t.Run("returns fallback when env var is not set", func(t *testing.T) {
+		if value := getEnvOrDefault("REGISTRY_BROKER_DELEGATION_EXAMPLE_MISSING", "fallback"); value != "fallback" {
+			t.Fatalf("expected fallback, got %s", value)
+		}
+	})
+
+	t.Run("returns env var value when set", func(t *testing.T) {
+		t.Setenv("REGISTRY_BROKER_DELEGATION_EXAMPLE_SET", "env-value")
+
+		if value := getEnvOrDefault("REGISTRY_BROKER_DELEGATION_EXAMPLE_SET", "fallback"); value != "env-value" {
+			t.Fatalf("expected env-value, got %s", value)
+		}
+	})
+
+	t.Run("returns trimmed env var value when set with whitespace", func(t *testing.T) {
+		t.Setenv("REGISTRY_BROKER_DELEGATION_EXAMPLE_SPACED", "  env-value  ")
+
+		if value := getEnvOrDefault("REGISTRY_BROKER_DELEGATION_EXAMPLE_SPACED", "fallback"); value != "env-value" {
+			t.Fatalf("expected env-value, got %s", value)
+		}
+	})
 }

pkg/registrybroker/delegation_plan_test.go

@@ -105,7 +105,14 @@ func TestDelegate(t *testing.T) {
 	if len(response.Opportunities) != 1 {
 		t.Fatalf("expected one opportunity, got %d", len(response.Opportunities))
 	}
-	candidate := response.Opportunities[0].Candidates[0]
+	if response.Extras["extraRootField"] != "preserved" {
+		t.Fatalf("expected additive root field to survive, got %#v", response.Extras)
+	}
+	opportunity := response.Opportunities[0]
+	if opportunity.Extras["extraOpportunityField"] != "preserved" {
+		t.Fatalf("expected additive opportunity field to survive, got %#v", opportunity.Extras)
+	}
+	candidate := opportunity.Candidates[0]
 	if candidate.Registry != "hcs-11" {
 		t.Fatalf("expected registry to parse, got %q", candidate.Registry)
 	}
@@ -115,6 +122,9 @@ func TestDelegate(t *testing.T) {
 	if candidate.Verified == nil || !*candidate.Verified {
 		t.Fatal("expected verified candidate")
 	}
+	if candidate.Extras["extraCandidateField"] != "preserved" {
+		t.Fatalf("expected additive candidate field to survive, got %#v", candidate.Extras)
+	}
 	if candidate.Agent["extraAgentField"] != "preserved" {
 		t.Fatalf("expected additive agent field to survive, got %#v", candidate.Agent)
 	}

pkg/registrybroker/types.go

@@ -2,6 +2,7 @@ package registrybroker
 
 import (
 	"context"
+	"encoding/json"
 	"net/http"
 	"time"
 )
@@ -107,6 +108,7 @@ type DelegationPlanCandidate struct {
 	Reasons                []string   `json:"reasons,omitempty"`
 	SuggestedMessage       string     `json:"suggestedMessage,omitempty"`
 	Agent                  JSONObject `json:"agent,omitempty"`
+	Extras                 JSONObject `json:"-"`
 }
 
 type DelegationOpportunity struct {
@@ -122,6 +124,7 @@ type DelegationOpportunity struct {
 	Languages     []string                  `json:"languages,omitempty"`
 	Artifacts     []string                  `json:"artifacts,omitempty"`
 	Candidates    []DelegationPlanCandidate `json:"candidates,omitempty"`
+	Extras        JSONObject                `json:"-"`
 }
 
 type DelegationPlanResponse struct {
@@ -137,6 +140,118 @@ type DelegationPlanResponse struct {
 	LocalFirstReason string                        `json:"localFirstReason,omitempty"`
 	Recommendation   *DelegationPlanRecommendation `json:"recommendation,omitempty"`
 	Opportunities    []DelegationOpportunity       `json:"opportunities,omitempty"`
+	Extras           JSONObject                    `json:"-"`
+}
+
+func (c *DelegationPlanCandidate) UnmarshalJSON(data []byte) error {
+	type candidateAlias DelegationPlanCandidate
+	aux := candidateAlias{}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	candidate := DelegationPlanCandidate(aux)
+	extras, err := extractUnknownFields(
+		data,
+		"uaid",
+		"label",
+		"registry",
+		"score",
+		"trustScore",
+		"verified",
+		"communicationSupported",
+		"availability",
+		"explanation",
+		"matchedQueries",
+		"matchedRoles",
+		"matchedProtocols",
+		"matchedSurfaces",
+		"matchedLanguages",
+		"matchedArtifacts",
+		"matchedTaskTags",
+		"reasons",
+		"suggestedMessage",
+		"agent",
+	)
+	if err != nil {
+		return err
+	}
+	candidate.Extras = extras
+	*c = candidate
+	return nil
+}
+
+func (o *DelegationOpportunity) UnmarshalJSON(data []byte) error {
+	type opportunityAlias DelegationOpportunity
+	aux := opportunityAlias{}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	opportunity := DelegationOpportunity(aux)
+	extras, err := extractUnknownFields(
+		data,
+		"id",
+		"title",
+		"reason",
+		"role",
+		"type",
+		"suggestedMode",
+		"searchQueries",
+		"protocols",
+		"surfaces",
+		"languages",
+		"artifacts",
+		"candidates",
+	)
+	if err != nil {
+		return err
+	}
+	opportunity.Extras = extras
+	*o = opportunity
+	return nil
+}
+
+func (r *DelegationPlanResponse) UnmarshalJSON(data []byte) error {
+	type responseAlias DelegationPlanResponse
+	aux := responseAlias{}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	response := DelegationPlanResponse(aux)
+	extras, err := extractUnknownFields(
+		data,
+		"task",
+		"context",
+		"summary",
+		"intents",
+		"surfaces",
+		"protocols",
+		"languages",
+		"artifacts",
+		"shouldDelegate",
+		"localFirstReason",
+		"recommendation",
+		"opportunities",
+	)
+	if err != nil {
+		return err
+	}
+	response.Extras = extras
+	*r = response
+	return nil
+}
+
+func extractUnknownFields(data []byte, knownKeys ...string) (JSONObject, error) {
+	var payload map[string]any
+	if err := json.Unmarshal(data, &payload); err != nil {
+		return nil, err
+	}
+	for _, key := range knownKeys {
+		delete(payload, key)
+	}
+	if len(payload) == 0 {
+		return nil, nil
+	}
+	return JSONObject(payload), nil
 }
 
 type VectorSearchFilter struct {