diff --git a/cmd/orchestra/main.go b/cmd/orchestra/main.go
index 77d2fc1..ad9bd00 100644
--- a/cmd/orchestra/main.go
+++ b/cmd/orchestra/main.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"orchestra/internal/authz"
@@ -121,6 +122,31 @@ func main() {
 		}
 		json.NewEncoder(w).Encode(s.Events(n))
 	})
+	mux.HandleFunc("/v1/artifacts", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		// Reports and handoffs are content-addressed evidence. Keep uploads
+		// bounded because event payloads only carry their resulting hash.
+		r.Body = http.MaxBytesReader(w, r.Body, 4<<20)
+		b, err := io.ReadAll(r.Body)
+		if err != nil {
+			http.Error(w, "artifact too large or unreadable", http.StatusRequestEntityTooLarge)
+			return
+		}
+		if len(b) == 0 {
+			http.Error(w, "artifact is empty", http.StatusBadRequest)
+			return
+		}
+		ref, err := s.PutArtifact(b)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		w.WriteHeader(http.StatusCreated)
+		json.NewEncoder(w).Encode(map[string]string{"ref": ref})
+	})
 	mux.HandleFunc("/v1/brief", func(w http.ResponseWriter, r *http.Request) {
 		to := time.Now().UTC()
 		from := to.Add(-12 * time.Hour)
diff --git a/progress.md b/progress.md
index 63b80bb..7bb1008 100644
--- a/progress.md
+++ b/progress.md
@@ -57,6 +57,8 @@ Item 1 substrate hardening pass: newly appended events use schema envelope versi
 
 Harness registration now uses configured `harness` and `protocol` fields, pings each configured herdr before exposing it to orchestration, selects Claude/Codex/opencode adapters accordingly, and skips unavailable or unsupported deployments at startup. This is an initial discovery/health slice; active-session discovery and ongoing heartbeats remain open.
 
+Added bounded `POST /v1/artifacts` CAS upload support for report/handoff evidence. It returns the verified content hash used by lifecycle events and rejects empty or oversized uploads.
+
 Recommended order:
 
 1. Add the orchestration coordinator: lease → worktree → harness session → bootstrap → lifecycle events.