diff --git a/checker/server.go b/checker/server.go
index 8b2eb31..86e6a4b 100644
--- a/checker/server.go
+++ b/checker/server.go
@@ -259,7 +259,7 @@ func (s *Server) handleCollect(w http.ResponseWriter, r *http.Request) {
 	resp := ExternalCollectResponse{Data: json.RawMessage(raw)}
 
 	// Harvest discovery entries from the native Go value, before it goes
-	// out of scope. No re-parse; DiscoverEntries operates on the same
+	// out of scope. No re-parse — DiscoverEntries operates on the same
 	// object that was just marshaled above.
 	if dp, ok := s.provider.(DiscoveryPublisher); ok {
 		entries, derr := dp.DiscoverEntries(data)
diff --git a/checker/server_test.go b/checker/server_test.go
index 6a228b6..e4c7854 100644
--- a/checker/server_test.go
+++ b/checker/server_test.go
@@ -429,7 +429,7 @@ func TestServer_Report_Metrics(t *testing.T) {
 }
 
 // TestServer_Report_Related verifies the remote /report path wires
-// ExternalReportRequest.Related through to the provider's ReportContext,
+// ExternalReportRequest.Related through to the provider's ReportContext —
 // the fix for the "remote checkers can't see related observations" gap.
 func TestServer_Report_Related(t *testing.T) {
 	var gotRelated []RelatedObservation
diff --git a/checker/types.go b/checker/types.go
index 9099a2f..3112b77 100644
--- a/checker/types.go
+++ b/checker/types.go
@@ -245,7 +245,7 @@ type CheckRuleWithOptions interface {
 // DiscoveryPublisher can, during rule evaluation, fetch the latest
 // observations that cover those entries and fold them into its own states.
 //
-// GetRelated returns an empty slice (not an error) when there is nothing
+// GetRelated returns an empty slice — not an error — when there is nothing
 // to relate (no entries originally published, no downstream observation
 // yet, no downstream checker registered for the entry type, …). Callers
 // handle that as "no related data", typically skipping optional sections.
@@ -275,7 +275,7 @@ type RelatedObservation struct {
 	CollectedAt time.Time `json:"collectedAt"`
 
 	// Ref matches DiscoveryEntry.Ref of the entry this observation covers.
-	// Opaque to the SDK; meaningful within the producer/consumer contract.
+	// Opaque to the SDK — meaningful within the producer/consumer contract.
 	Ref string `json:"ref"`
 }
 
@@ -290,7 +290,7 @@ type CheckAggregator interface {
 //
 // The method set is deliberately tiny: a single primary payload (Data) and
 // a query for related observations by key (Related). Hosts return nil from
-// Related when there is nothing to relate; reporters must tolerate that.
+// Related when there is nothing to relate — reporters must tolerate that.
 type ReportContext interface {
 	Data() json.RawMessage
 	Related(key ObservationKey) []RelatedObservation
@@ -417,12 +417,13 @@ type ExternalCollectResponse struct {
 // The SDK treats Payload as an opaque byte string: producer and consumer
 // checkers agree on a schema through a separate contract (typically a small
 // shared Go package imported by both). This keeps the SDK free of
-// protocol-specific concepts; new entry families (TLS endpoint, HTTP probe,
+// protocol-specific concepts — new entry families (TLS endpoint, HTTP probe,
 // ACME challenge, DNSSEC key, …) can appear without touching it.
 //
 // Entries are ingested by happyDomain into a separate index. Each new
 // collection from the same source atomically replaces the set of entries
-// previously published for the same (producer, target) pair.
+// previously published for the same (producer, target) pair; see
+// DISCOVERY.md for the host-side semantics.
 type DiscoveryEntry struct {
 	// Type names the contract Payload follows, e.g. "tls.endpoint" or
 	// "http.probe". Producers and consumers match on this string; the SDK
@@ -470,7 +471,7 @@ type ExternalEvaluateResponse struct {
 // ExternalReportRequest is sent to POST /report on a remote checker endpoint.
 //
 // Related carries observations produced by other checkers on DiscoveryEntry
-// records originally published by the target of this report, that is, the
+// 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;
 // when absent, the remote checker receives a context that reports no