checker: thread rule states into ReportContext

Reporters can now read rule output via ctx.States() instead of
re-deriving severity/hints from the raw payload, keeping the rules
screen and the HTML report aligned on a single source of truth.

checker/server/interactive.go

@@ -96,14 +96,15 @@ func (s *Server) handleCheckForm(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *Server) handleCheckSubmit(w http.ResponseWriter, r *http.Request) {
+	fields := s.interactive.RenderForm()
 	if err := r.ParseForm(); err != nil {
-		s.renderCheckForm(w, s.interactive.RenderForm(), fmt.Sprintf("invalid form: %v", err))
+		s.renderCheckForm(w, fields, fmt.Sprintf("invalid form: %v", err))
 		return
 	}
 
 	opts, err := s.interactive.ParseForm(r)
 	if err != nil {
-		s.renderCheckForm(w, s.interactive.RenderForm(), err.Error())
+		s.renderCheckForm(w, fields, err.Error())
 		return
 	}
 
@@ -135,7 +136,7 @@ func (s *Server) handleCheckSubmit(w http.ResponseWriter, r *http.Request) {
 		result.States = s.evaluateRules(r.Context(), obs, opts, nil)
 	}
 
-	ctx := checker.NewReportContext(raw, related)
+	ctx := checker.NewReportContext(raw, related, result.States)
 
 	if reporter, ok := s.provider.(checker.CheckerHTMLReporter); ok {
 		html, rerr := reporter.GetHTMLReport(ctx)

checker/server/interactive_test.go

@@ -355,6 +355,65 @@ func TestCheck_Submit_RunsSiblingAndExposesRelated(t *testing.T) {
 	}
 }
 
+// interactiveStatesPeekingProvider implements Interactive + HTMLReporter
+// and captures the ReportContext.States() seen at GetHTMLReport time.
+type interactiveStatesPeekingProvider struct {
+	key  checker.ObservationKey
+	def  *checker.CheckerDefinition
+	seen *[]checker.CheckState
+}
+
+func (p *interactiveStatesPeekingProvider) Key() checker.ObservationKey { return p.key }
+func (p *interactiveStatesPeekingProvider) Collect(ctx context.Context, opts checker.CheckerOptions) (any, error) {
+	return map[string]string{"ok": "1"}, nil
+}
+func (p *interactiveStatesPeekingProvider) Definition() *checker.CheckerDefinition { return p.def }
+func (p *interactiveStatesPeekingProvider) RenderForm() []checker.CheckerOptionField {
+	return []checker.CheckerOptionField{{Id: "domain", Type: "string"}}
+}
+func (p *interactiveStatesPeekingProvider) ParseForm(r *http.Request) (checker.CheckerOptions, error) {
+	return checker.CheckerOptions{"domain": r.FormValue("domain")}, nil
+}
+func (p *interactiveStatesPeekingProvider) GetHTMLReport(ctx checker.ReportContext) (string, error) {
+	if p.seen != nil {
+		*p.seen = ctx.States()
+	}
+	return "<p>ok</p>", nil
+}
+
+// TestCheck_Submit_ThreadsStatesIntoReport verifies that CheckStates
+// produced by evaluateRules during POST /check are threaded into the
+// ReportContext handed to GetHTMLReport. Without this wiring, the /check
+// UI can show states in its own section but the embedded report would
+// have to re-derive severity/hints from Data.
+func TestCheck_Submit_ThreadsStatesIntoReport(t *testing.T) {
+	var seen []checker.CheckState
+	p := &interactiveStatesPeekingProvider{
+		key: "test",
+		def: &checker.CheckerDefinition{
+			ID:    "test",
+			Rules: []checker.CheckRule{&dummyRule{name: "rule1", desc: "first"}},
+		},
+		seen: &seen,
+	}
+	srv := New(p)
+	defer srv.Close()
+
+	rec := postForm(srv.Handler(), "/check", url.Values{"domain": {"example.com"}})
+	if rec.Code != http.StatusOK {
+		t.Fatalf("POST /check = %d, want 200", rec.Code)
+	}
+	if len(seen) != 1 {
+		t.Fatalf("reporter saw %d states, want 1", len(seen))
+	}
+	if seen[0].RuleName != "rule1" {
+		t.Errorf("state RuleName = %q, want %q", seen[0].RuleName, "rule1")
+	}
+	if seen[0].Status != checker.StatusOK {
+		t.Errorf("state Status = %v, want %v", seen[0].Status, checker.StatusOK)
+	}
+}
+
 func TestCheck_Submit_NoSibling_LeavesRelatedEmpty(t *testing.T) {
 	p := &interactiveProvider{
 		testProvider: &testProvider{

checker/server/server.go

@@ -357,7 +357,7 @@ func (s *Server) handleReport(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		html, err := reporter.GetHTMLReport(checker.NewReportContext(req.Data, req.Related))
+		html, err := reporter.GetHTMLReport(checker.NewReportContext(req.Data, req.Related, req.States))
 		if err != nil {
 			http.Error(w, fmt.Sprintf("failed to generate HTML report: %v", err), http.StatusInternalServerError)
 			return
@@ -375,7 +375,7 @@ func (s *Server) handleReport(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	metrics, err := reporter.ExtractMetrics(checker.NewReportContext(req.Data, req.Related), time.Now())
+	metrics, err := reporter.ExtractMetrics(checker.NewReportContext(req.Data, req.Related, req.States), time.Now())
 	if err != nil {
 		writeJSON(w, http.StatusInternalServerError, map[string]string{
 			"error": fmt.Sprintf("failed to extract metrics: %v", err),

checker/server/server_test.go

@@ -542,6 +542,107 @@ func (p *relatedPeekingProvider) GetHTMLReport(ctx checker.ReportContext) (strin
 	return "<p>ok</p>", nil
 }
 
+// statesPeekingProvider captures the ReportContext's States slice at
+// GetHTMLReport / ExtractMetrics time.
+type statesPeekingProvider struct {
+	base       *testProvider
+	htmlSeen   *[]checker.CheckState
+	metricSeen *[]checker.CheckState
+}
+
+func (p *statesPeekingProvider) Key() checker.ObservationKey { return p.base.Key() }
+func (p *statesPeekingProvider) Collect(ctx context.Context, opts checker.CheckerOptions) (any, error) {
+	return p.base.Collect(ctx, opts)
+}
+func (p *statesPeekingProvider) Definition() *checker.CheckerDefinition { return p.base.definition }
+func (p *statesPeekingProvider) GetHTMLReport(ctx checker.ReportContext) (string, error) {
+	if p.htmlSeen != nil {
+		*p.htmlSeen = ctx.States()
+	}
+	return "<p>ok</p>", nil
+}
+func (p *statesPeekingProvider) ExtractMetrics(ctx checker.ReportContext, t time.Time) ([]checker.CheckMetric, error) {
+	if p.metricSeen != nil {
+		*p.metricSeen = ctx.States()
+	}
+	return []checker.CheckMetric{{Name: "m1", Value: 1.0, Timestamp: t}}, nil
+}
+
+// TestServer_Report_States_HTML verifies ExternalReportRequest.States is
+// threaded into the ReportContext seen by the HTML reporter.
+func TestServer_Report_States_HTML(t *testing.T) {
+	var seen []checker.CheckState
+	base := &testProvider{
+		key:        "test",
+		definition: &checker.CheckerDefinition{ID: "test-checker", Rules: []checker.CheckRule{}},
+	}
+	srv := New(&statesPeekingProvider{base: base, htmlSeen: &seen})
+	defer srv.Close()
+
+	states := []checker.CheckState{
+		{Status: checker.StatusCrit, Message: "broken", RuleName: "r1", Code: "bad", Subject: "host.example"},
+	}
+	req := checker.ExternalReportRequest{
+		Key:    "test",
+		Data:   json.RawMessage(`{}`),
+		States: states,
+	}
+	rec := doRequest(srv.Handler(), "POST", "/report", req, map[string]string{"Accept": "text/html"})
+	if rec.Code != http.StatusOK {
+		t.Fatalf("POST /report = %d, want 200", rec.Code)
+	}
+	if len(seen) != 1 || seen[0].RuleName != "r1" || seen[0].Code != "bad" || seen[0].Subject != "host.example" {
+		t.Errorf("reporter saw states = %+v, want single state {RuleName:r1, Code:bad, Subject:host.example}", seen)
+	}
+}
+
+// TestServer_Report_States_Metrics verifies the States passthrough on the
+// metrics path as well.
+func TestServer_Report_States_Metrics(t *testing.T) {
+	var seen []checker.CheckState
+	base := &testProvider{
+		key:        "test",
+		definition: &checker.CheckerDefinition{ID: "test-checker", Rules: []checker.CheckRule{}},
+	}
+	srv := New(&statesPeekingProvider{base: base, metricSeen: &seen})
+	defer srv.Close()
+
+	req := checker.ExternalReportRequest{
+		Key:    "test",
+		Data:   json.RawMessage(`{}`),
+		States: []checker.CheckState{{Status: checker.StatusWarn, RuleName: "r1"}},
+	}
+	rec := doRequest(srv.Handler(), "POST", "/report", req, map[string]string{"Accept": "application/json"})
+	if rec.Code != http.StatusOK {
+		t.Fatalf("POST /report = %d, want 200", rec.Code)
+	}
+	if len(seen) != 1 || seen[0].RuleName != "r1" {
+		t.Errorf("reporter saw states = %+v, want single state with RuleName=r1", seen)
+	}
+}
+
+// TestServer_Report_States_Absent verifies that omitting States in the
+// request yields a nil States() slice on the reporter side (graceful
+// degradation for hosts that don't thread evaluate→report yet).
+func TestServer_Report_States_Absent(t *testing.T) {
+	seen := []checker.CheckState{{Status: checker.StatusOK}} // non-nil sentinel
+	base := &testProvider{
+		key:        "test",
+		definition: &checker.CheckerDefinition{ID: "test-checker", Rules: []checker.CheckRule{}},
+	}
+	srv := New(&statesPeekingProvider{base: base, htmlSeen: &seen})
+	defer srv.Close()
+
+	req := checker.ExternalReportRequest{Key: "test", Data: json.RawMessage(`{}`)}
+	rec := doRequest(srv.Handler(), "POST", "/report", req, map[string]string{"Accept": "text/html"})
+	if rec.Code != http.StatusOK {
+		t.Fatalf("POST /report = %d, want 200", rec.Code)
+	}
+	if seen != nil {
+		t.Errorf("States() = %+v, want nil when ExternalReportRequest.States is absent", seen)
+	}
+}
+
 func TestServer_Report_BadBody(t *testing.T) {
 	p := &testProvider{
 		key:        "test",

checker/types.go

@@ -298,32 +298,40 @@ type CheckAggregator interface {
 	Aggregate(states []CheckState) CheckState
 }
 
-// ReportContext carries both the primary observation payload and any
+// ReportContext carries the primary observation payload, any observations
-// observations produced by other checkers that cover the same discovery
+// produced by other checkers that cover the same discovery entries, and the
-// entries. Hosts build a ReportContext and hand it to reporter methods.
+// CheckStates produced by this checker's rules for the same observation.
+// Hosts build a ReportContext and hand it to reporter methods.
 //
-// The method set is deliberately tiny: a single primary payload (Data) and
+// Reporters use States() to render rule-driven sections (for example a
-// a query for related observations by key (Related). Hosts return nil from
+// "fix these first" list) without re-deriving severity or hints from the
-// Related when there is nothing to relate; reporters must tolerate that.
+// raw payload. Hosts that have not yet threaded rule output into the
+// report pipeline return nil; reporters must treat a nil or empty slice
+// as "not provided" and fall back to a data-only rendering. The same
+// nil-tolerance applies to Related(key).
 type ReportContext interface {
 	Data() json.RawMessage
 	Related(key ObservationKey) []RelatedObservation
+	States() []CheckState
 }
 
-// NewReportContext returns a ReportContext backed by a primary payload and
+// NewReportContext returns a ReportContext backed by a primary payload, a
-// a pre-resolved map of related observations by key. The SDK's /report HTTP
+// pre-resolved map of related observations by key, and the CheckStates
-// handler uses this to wrap ExternalReportRequest contents; hosts and tests
+// produced by the checker's rules on this observation. The SDK's /report
-// can use it whenever they already have the related observations in memory.
+// HTTP handler uses this to wrap ExternalReportRequest contents; hosts and
+// tests can use it whenever they already have that material in memory.
 //
-// Passing a nil or empty related map is fine; Related(key) will then return
+// Passing a nil related map or a nil states slice is fine; Related(key)
-// nil, just like StaticReportContext.
+// and States() will then return nil respectively. Use StaticReportContext
-func NewReportContext(data json.RawMessage, related map[ObservationKey][]RelatedObservation) ReportContext {
+// as a shorthand when both are absent.
-	return fixedReportContext{data: data, related: related}
+func NewReportContext(data json.RawMessage, related map[ObservationKey][]RelatedObservation, states []CheckState) ReportContext {
+	return fixedReportContext{data: data, related: related, states: states}
 }
 
-// StaticReportContext is a shorthand for NewReportContext(data, nil): a
+// StaticReportContext is a shorthand for NewReportContext(data, nil, nil):
-// ReportContext with a primary payload and no related observations.
+// a ReportContext with a primary payload, no related observations, and no
-// Intended for tests and ad-hoc callers that have no lineage to supply.
+// rule states. Intended for tests and ad-hoc callers that have no lineage
+// or rule output to supply.
 func StaticReportContext(data json.RawMessage) ReportContext {
 	return fixedReportContext{data: data}
 }
@@ -331,6 +339,7 @@ func StaticReportContext(data json.RawMessage) ReportContext {
 type fixedReportContext struct {
 	data    json.RawMessage
 	related map[ObservationKey][]RelatedObservation
+	states  []CheckState
 }
 
 func (f fixedReportContext) Data() json.RawMessage { return f.data }
@@ -340,6 +349,7 @@ func (f fixedReportContext) Related(key ObservationKey) []RelatedObservation {
 	}
 	return f.related[key]
 }
+func (f fixedReportContext) States() []CheckState { return f.states }
 
 // CheckerHTMLReporter is an optional interface that observation providers can
 // implement to render their stored data as a full HTML document (for iframe embedding).
@@ -486,13 +496,20 @@ type ExternalEvaluateResponse struct {
 // Related carries observations produced by other checkers on DiscoveryEntry
 // records originally published by the target of this report, that is, the
 // cross-checker lineage that ObservationGetter.GetRelated would expose in
-// the in-process path. The host composes it before making the HTTP request;
+// the in-process path. States carries the CheckStates the host produced by
-// when absent, the remote checker receives a context that reports no
+// evaluating this checker's rules against the same observation, letting
-// related observations (equivalent to StaticReportContext).
+// reporters render rule-driven sections (for example a "fix these first"
+// list) without re-deriving severity or hints from Data.
+//
+// The host composes both fields before making the HTTP request. When both
+// are absent, the remote checker receives a context equivalent to
+// StaticReportContext (no related observations and no states); the
+// reporter then falls back to a data-only rendering.
 type ExternalReportRequest struct {
 	Key     ObservationKey                          `json:"key"`
 	Data    json.RawMessage                         `json:"data"`
 	Related map[ObservationKey][]RelatedObservation `json:"related,omitempty"`
+	States  []CheckState                            `json:"states,omitempty"`
 }
 
 // HealthResponse is returned by GET /health on a remote checker endpoint.

checker/types_test.go

@@ -17,6 +17,7 @@ package checker
 import (
 	"context"
 	"encoding/json"
+	"reflect"
 	"testing"
 )
 
@@ -156,6 +157,54 @@ func TestCheckerDefinition_BuildRulesInfo(t *testing.T) {
 	}
 }
 
+// Compile-time check that fixedReportContext implements ReportContext.
+var _ ReportContext = fixedReportContext{}
+
+func TestStaticReportContext_NoExtras(t *testing.T) {
+	ctx := StaticReportContext(json.RawMessage(`{"k":"v"}`))
+	if string(ctx.Data()) != `{"k":"v"}` {
+		t.Errorf("Data() = %s, want %s", ctx.Data(), `{"k":"v"}`)
+	}
+	if ctx.Related("any") != nil {
+		t.Error("Related(any) should be nil for StaticReportContext")
+	}
+	if ctx.States() != nil {
+		t.Error("States() should be nil for StaticReportContext")
+	}
+}
+
+func TestNewReportContext_NilStates(t *testing.T) {
+	ctx := NewReportContext(json.RawMessage(`{}`), nil, nil)
+	if ctx.States() != nil {
+		t.Errorf("States() = %v, want nil", ctx.States())
+	}
+}
+
+func TestNewReportContext_PassesStates(t *testing.T) {
+	states := []CheckState{
+		{Status: StatusWarn, Message: "heads up", RuleName: "r1"},
+		{Status: StatusCrit, Message: "fix me", RuleName: "r2", Subject: "host.example"},
+	}
+	ctx := NewReportContext(json.RawMessage(`{}`), nil, states)
+	got := ctx.States()
+	if !reflect.DeepEqual(got, states) {
+		t.Errorf("States() = %+v, want %+v", got, states)
+	}
+}
+
+func TestNewReportContext_PassesRelated(t *testing.T) {
+	rel := map[ObservationKey][]RelatedObservation{
+		"other.key": {{CheckerID: "other", Key: "other.key", Ref: "r1"}},
+	}
+	ctx := NewReportContext(json.RawMessage(`{}`), rel, nil)
+	if got := ctx.Related("other.key"); len(got) != 1 || got[0].CheckerID != "other" {
+		t.Errorf("Related(other.key) = %+v, want one entry with CheckerID=other", got)
+	}
+	if ctx.Related("missing") != nil {
+		t.Error("Related(missing) should be nil")
+	}
+}
+
 func TestRegisterChecker_EmptyIDRejected(t *testing.T) {
 	resetRegistries()
 	RegisterChecker(&CheckerDefinition{ID: "", Name: "bad"})