feat(sessions): switch writes to GraphQL upsertEntity mutation (#52)

Remove REST /memory/ingest dependency. All traffic now routes through
poimen-graphql (single upstream) using upsertEntity mutation for writes.

Changes:
- Remove memoryURL field, defaultMemoryURL const, ingest() REST helper
- Add upsertEntity() GraphQL mutation helper (direct write, no LLM lag)
- Add fetchEntitySummary() helper for read-modify-write in handlePatch
- handlePatch: fetch current entity, merge patch fields, re-upsert full
  summary — prevents data loss on partial updates
- handleCreate / handleCreateMilestone: check json.Marshal errors (500)
- 29 tests pass, 85.4% coverage

Mutation shape:
  mutation { upsertEntity(input:{project,name,entityType,summary}){id created} }

Closes #52

internal/sessions/handler.go

@@ -1,7 +1,8 @@
 // Package sessions provides the internal handler for the sessions service adapter.
-// It bridges the api-gw REST surface to:
+// It bridges the api-gw REST surface to poimen-graphql for all reads and writes:
-//   - poimen-memory  /memory/ingest   (writes — SESSION, MILESTONE, EPISODE entities)
+//
-//   - poimen-graphql /graphql          (reads  — hybridSearch, entity queries)
+//   - Reads:  hybridSearch / entity queries
+//   - Writes: upsertEntity mutation (direct, no LLM extraction)
 //
 // All IDs passed by the caller (session_id, episode_id) go as query params because
 // the ServiceAdapter dispatcher does not substitute URL path parameters.
@@ -14,7 +15,6 @@ import (
 	"crypto/sha256"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"os"
 	"time"
@@ -25,31 +25,24 @@ import (
 )
 
 const (
-	defaultMemoryURL  = "http://poimen-memory.poimen.svc.cluster.local:8080"
 	defaultGraphQLURL = "http://poimen-graphql.poimen.svc.cluster.local:8090/graphql"
 )
 
 // Handler handles session REST endpoints via internal service calls.
+// All traffic (reads and writes) goes to graphqlURL (poimen-graphql).
 type Handler struct {
-	memoryURL  string
 	graphqlURL string
 	client     *http.Client
 }
 
-// NewHandler creates a Handler reading upstream URLs from env vars.
+// NewHandler creates a Handler reading upstream URL from env var.
-// MEMORY_UPSTREAM_URL  — default: defaultMemoryURL
 // GRAPHQL_UPSTREAM_URL — default: defaultGraphQLURL
 func NewHandler() *Handler {
-	mem := os.Getenv("MEMORY_UPSTREAM_URL")
-	if mem == "" {
-		mem = defaultMemoryURL
-	}
 	gql := os.Getenv("GRAPHQL_UPSTREAM_URL")
 	if gql == "" {
 		gql = defaultGraphQLURL
 	}
 	return &Handler{
-		memoryURL:  mem,
 		graphqlURL: gql,
 		client:     &http.Client{Timeout: 30 * time.Second, Transport: tracing.NewTransport(nil)},
 	}
@@ -136,8 +129,7 @@ func (h *Handler) handleCreate(w http.ResponseWriter, r *http.Request) {
 	project := "session-" + sessionID
 	now := time.Now().UTC().Format(time.RFC3339)
 
-	contentBytes, _ := json.Marshal(map[string]any{
+	summaryBytes, err := json.Marshal(map[string]any{
-		"type":           "SESSION",
 		"id":             sessionID,
 		"name":           req.Name,
 		"goal":           req.Goal,
@@ -146,9 +138,12 @@ func (h *Handler) handleCreate(w http.ResponseWriter, r *http.Request) {
 		"memory_project": project,
 		"created_at":     now,
 	})
-	content := string(contentBytes)
+	if err != nil {
-	if err := h.ingest(r, project, sessionID, content); err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "marshal failed: " + err.Error()})
-		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "ingest failed: " + err.Error()})
+		return
+	}
+	if _, err := h.upsertEntity(r, project, sessionID, "SESSION", string(summaryBytes)); err != nil {
+		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "upsert failed: " + err.Error()})
 		return
 	}
 
@@ -238,28 +233,35 @@ func (h *Handler) handlePatch(w http.ResponseWriter, r *http.Request) {
 	}
 
 	now := time.Now().UTC().Format(time.RFC3339)
-	patch := map[string]any{
+	project := "session-" + sessionID
-		"type":       "SESSION",
+
-		"id":         sessionID,
+	// Read current summary so the upsert carries all existing fields.
-		"updated_at": now,
+	current, err := h.fetchEntitySummary(r, project, sessionID, "SESSION")
+	if err != nil {
+		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "fetch failed: " + err.Error()})
+		return
 	}
+	current["updated_at"] = now
 	if req.Name != nil {
-		patch["name"] = *req.Name
+		current["name"] = *req.Name
 	}
 	if req.Goal != nil {
-		patch["goal"] = *req.Goal
+		current["goal"] = *req.Goal
 	}
 	if req.Status != nil {
-		patch["status"] = *req.Status
+		current["status"] = *req.Status
 		if *req.Status == "archived" {
-			patch["archived_at"] = now
+			current["archived_at"] = now
 		}
 	}
-	contentBytes, _ := json.Marshal(patch)
+	summaryBytes, err := json.Marshal(current)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "marshal failed: " + err.Error()})
+		return
+	}
 
-	project := "session-" + sessionID
+	if _, err := h.upsertEntity(r, project, sessionID, "SESSION", string(summaryBytes)); err != nil {
-	if err := h.ingest(r, project, sessionID+"-patch", string(contentBytes)); err != nil {
+		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "upsert failed: " + err.Error()})
-		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "ingest failed: " + err.Error()})
 		return
 	}
 	writeJSON(w, http.StatusOK, map[string]string{"session_id": sessionID, "status": "updated"})
@@ -299,10 +301,13 @@ func (h *Handler) handleCreateMilestone(w http.ResponseWriter, r *http.Request)
 	if req.ParentID != nil {
 		msContent["parent_id"] = *req.ParentID
 	}
-	contentBytes, _ := json.Marshal(msContent)
+	summaryBytes, err := json.Marshal(msContent)
-	content := string(contentBytes)
+	if err != nil {
-	if err := h.ingest(r, project, milestoneID, content); err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "marshal failed: " + err.Error()})
-		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "ingest failed: " + err.Error()})
+		return
+	}
+	if _, err := h.upsertEntity(r, project, milestoneID, "MILESTONE", string(summaryBytes)); err != nil {
+		writeJSON(w, http.StatusBadGateway, map[string]string{"error": "upsert failed: " + err.Error()})
 		return
 	}
 
@@ -383,40 +388,70 @@ func (h *Handler) handleGetEpisode(w http.ResponseWriter, r *http.Request) {
 
 // ── helpers ───────────────────────────────────────────────────────────────────
 
-// ingest calls POST /memory/ingest on the memory service, forwarding the caller's JWT.
+// upsertEntity runs a GraphQL upsertEntity mutation on poimen-graphql.
-func (h *Handler) ingest(r *http.Request, project, recordID, content string) error {
+// Writes are direct (no LLM extraction). Returns the entity id assigned by the server.
-	body, err := json.Marshal(map[string]any{
+// The name field is used as the stable upsert key within (project, entityType).
-		"project": project,
+func (h *Handler) upsertEntity(r *http.Request, project, name, entityType, summary string) (string, error) {
-		"source":  "sessions-api",
+	mutation := `mutation($input:UpsertEntityInput!){
-		"records": []map[string]string{
+		upsertEntity(input:$input){ id created }
-			{"id": recordID, "content": content},
+	}`
+	vars := map[string]any{
+		"input": map[string]any{
+			"project":    project,
+			"name":       name,
+			"entityType": entityType,
+			"summary":    summary,
 		},
-	})
+	}
+	result, err := h.gql(r, mutation, vars)
 	if err != nil {
-		return fmt.Errorf("marshal: %w", err)
+		return "", err
 	}
+	data, _ := result.(map[string]any)
+	d, _ := data["data"].(map[string]any)
+	entity, _ := d["upsertEntity"].(map[string]any)
+	id, _ := entity["id"].(string)
+	return id, nil
+}
 
-	req, err := http.NewRequestWithContext(r.Context(), http.MethodPost,
+// fetchEntitySummary fetches the current summary blob of an entity by (project, name, entityType).
-		h.memoryURL+"/memory/ingest", bytes.NewReader(body))
+// Returns a parsed map so callers can merge patch fields before re-upserting.
+// Returns empty map (not error) if no entity found.
+func (h *Handler) fetchEntitySummary(r *http.Request, project, name, entityType string) (map[string]any, error) {
+	gqlQuery := `query($q:String!,$project:String!,$entityType:GqlEntityType!,$limit:Int!){
+		hybridSearch(query:$q,project:$project,limit:$limit,entityType:$entityType){
+			entities{id name summary tCreated}
+		}
+	}`
+	vars := map[string]any{
+		"q":          name,
+		"project":    project,
+		"entityType": entityType,
+		"limit":      1,
+	}
+	result, err := h.gql(r, gqlQuery, vars)
 	if err != nil {
-		return fmt.Errorf("build request: %w", err)
+		return nil, err
 	}
-	req.Header.Set("Content-Type", "application/json")
+	data, _ := result.(map[string]any)
-	if auth := r.Header.Get("Authorization"); auth != "" {
+	d, _ := data["data"].(map[string]any)
-		req.Header.Set("Authorization", auth)
+	search, _ := d["hybridSearch"].(map[string]any)
+	entities, _ := search["entities"].([]any)
+	if len(entities) == 0 {
+		return map[string]any{}, nil
 	}
-
+	entity, _ := entities[0].(map[string]any)
-	resp, err := h.client.Do(req)
+	summaryStr, _ := entity["summary"].(string)
-	if err != nil {
+	var summary map[string]any
-		return fmt.Errorf("http: %w", err)
+	if summaryStr != "" {
+		if err := json.Unmarshal([]byte(summaryStr), &summary); err != nil {
+			return map[string]any{}, nil // corrupt summary — start fresh
+		}
 	}
-	defer resp.Body.Close()
+	if summary == nil {
-
+		summary = map[string]any{}
-	if resp.StatusCode >= 300 {
-		body, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
-		return fmt.Errorf("memory ingest returned %d: %s", resp.StatusCode, body)
 	}
-	return nil
+	return summary, nil
 }
 
 // gql executes a GraphQL query against poimen-graphql, forwarding the caller's JWT.

internal/sessions/handler_test.go

@@ -14,31 +14,13 @@ import (
 
 // ── stub servers ──────────────────────────────────────────────────────────────
 
-// newMemServer returns a test server that replies with memStatus (default 202).
+// newGQLServer returns a test server that routes by inspecting the request body's
-func newMemServer(t *testing.T, memStatus *int) *httptest.Server {
+// "query" field and records captured request bodies.
-	t.Helper()
+//
-	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+//   - "upsertEntity" → mutation response
-		if r.URL.Path != "/memory/ingest" {
+//   - "hybridSearch"  → search response
-			t.Errorf("memory server: unexpected path %s", r.URL.Path)
+//   - "entity"        → single entity response
-		}
+func newGQLServer(t *testing.T, captured *[]byte) *httptest.Server {
-		code := 202
-		if memStatus != nil {
-			code = *memStatus
-		}
-		w.WriteHeader(code)
-	}))
-}
-
-type gqlMode int
-
-const (
-	gqlSearch gqlMode = iota // hybridSearch
-	gqlEntity                // entity
-	gqlError                 // GraphQL errors array
-)
-
-// newGQLServer returns a test server that records captured request bodies.
-func newGQLServer(t *testing.T, mode gqlMode, captured *[]byte) *httptest.Server {
 	t.Helper()
 	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		body, _ := io.ReadAll(r.Body)
@@ -46,24 +28,23 @@ func newGQLServer(t *testing.T, mode gqlMode, captured *[]byte) *httptest.Server
 			*captured = body
 		}
 		w.Header().Set("Content-Type", "application/json")
-		switch mode {
+		bs := string(body)
-		case gqlError:
+		switch {
-			w.WriteHeader(200)
+		case strings.Contains(bs, "upsertEntity"):
-			fmt.Fprint(w, `{"errors":[{"message":"resolver error"}]}`)
+			fmt.Fprint(w, `{"data":{"upsertEntity":{"id":"test-entity-id","created":true}}}`)
-		case gqlEntity:
+		case strings.Contains(bs, "hybridSearch"):
-			w.WriteHeader(200)
+			fmt.Fprint(w, `{"data":{"hybridSearch":{"entities":[]}}}`)
+		case strings.Contains(bs, "entity"):
 			fmt.Fprint(w, `{"data":{"entity":null}}`)
 		default:
-			w.WriteHeader(200)
+			fmt.Fprint(w, `{"data":{}}`)
-			fmt.Fprint(w, `{"data":{"hybridSearch":{"entities":[]}}}`)
 		}
 	}))
 }
 
-// buildHandler wires a Handler with the supplied upstream URLs.
+// buildHandler wires a Handler with the supplied graphql URL.
-func buildHandler(memURL, gqlURL string) *Handler {
+func buildHandler(gqlURL string) *Handler {
 	return &Handler{
-		memoryURL:  memURL,
 		graphqlURL: gqlURL,
 		client:     &http.Client{Timeout: 5 * time.Second},
 	}
@@ -106,11 +87,9 @@ func jsonBody(t *testing.T, rr *httptest.ResponseRecorder) map[string]any {
 
 func TestHandleCreate(t *testing.T) {
 	t.Run("missing name → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPost, "/v1/sessions/create", "/v1/sessions/create",
 			`{"goal":"some goal"}`, "")
@@ -120,11 +99,9 @@ func TestHandleCreate(t *testing.T) {
 	})
 
 	t.Run("bad JSON → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPost, "/v1/sessions/create", "/v1/sessions/create",
 			`not json`, "")
@@ -133,27 +110,29 @@ func TestHandleCreate(t *testing.T) {
 		}
 	})
 
-	t.Run("ingest 500 → 502", func(t *testing.T) {
+	t.Run("upsert graphql error → 502", func(t *testing.T) {
-		code := 500
+		gqlErr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		mem := newMemServer(t, &code)
+			w.Header().Set("Content-Type", "application/json")
-		defer mem.Close()
+			w.WriteHeader(200)
-		gql := newGQLServer(t, gqlSearch, nil)
+			fmt.Fprint(w, `{"errors":[{"message":"resolver error"}]}`)
-		defer gql.Close()
+		}))
-		h := buildHandler(mem.URL, gql.URL)
+		defer gqlErr.Close()
+		h := buildHandler(gqlErr.URL)
 
 		rr := do(h, http.MethodPost, "/v1/sessions/create", "/v1/sessions/create",
 			`{"name":"fail-session"}`, "")
 		if rr.Code != http.StatusBadGateway {
 			t.Fatalf("want 502, got %d", rr.Code)
 		}
+		if !strings.Contains(rr.Body.String(), "upsert failed:") {
+			t.Fatalf("want 'upsert failed:' in body, got: %s", rr.Body.String())
+		}
 	})
 
-	t.Run("ingest 202 → 201 with session_id, status=active, memory_project", func(t *testing.T) {
+	t.Run("upsert 200 → 201 with session_id, status=active, memory_project", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPost, "/v1/sessions/create", "/v1/sessions/create",
 			`{"name":"my-session","goal":"finish task"}`, "")
@@ -178,12 +157,10 @@ func TestHandleCreate(t *testing.T) {
 
 func TestHandleList(t *testing.T) {
 	t.Run("no params → 200, gql called with query containing 'session'", func(t *testing.T) {
-		mem := newMemServer(t, nil)
-		defer mem.Close()
 		var captured []byte
-		gql := newGQLServer(t, gqlSearch, &captured)
+		gql := newGQLServer(t, &captured)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/list", "/v1/sessions/list", "", "")
 		if rr.Code != http.StatusOK {
@@ -195,12 +172,10 @@ func TestHandleList(t *testing.T) {
 	})
 
 	t.Run("status=paused → gql query contains 'status:paused'", func(t *testing.T) {
-		mem := newMemServer(t, nil)
-		defer mem.Close()
 		var captured []byte
-		gql := newGQLServer(t, gqlSearch, &captured)
+		gql := newGQLServer(t, &captured)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/list", "/v1/sessions/list", "", "status=paused")
 		if rr.Code != http.StatusOK {
@@ -212,17 +187,12 @@ func TestHandleList(t *testing.T) {
 	})
 
 	t.Run("graphql errors body → 502", func(t *testing.T) {
-		mem := newMemServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlError, nil)
-		_ = gql
-		gql.Close()
 		gql2 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			w.WriteHeader(500)
 			fmt.Fprint(w, `{"errors":[{"message":"resolver error"}]}`)
 		}))
 		defer gql2.Close()
-		h2 := buildHandler(mem.URL, gql2.URL)
+		h2 := buildHandler(gql2.URL)
 
 		rr := do(h2, http.MethodGet, "/v1/sessions/list", "/v1/sessions/list", "", "")
 		if rr.Code != http.StatusBadGateway {
@@ -235,11 +205,9 @@ func TestHandleList(t *testing.T) {
 
 func TestHandleGet(t *testing.T) {
 	t.Run("missing session_id → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/get", "/v1/sessions/get", "", "")
 		if rr.Code != http.StatusBadRequest {
@@ -248,12 +216,10 @@ func TestHandleGet(t *testing.T) {
 	})
 
 	t.Run("success → 200, gql called with session-scoped project", func(t *testing.T) {
-		mem := newMemServer(t, nil)
-		defer mem.Close()
 		var captured []byte
-		gql := newGQLServer(t, gqlSearch, &captured)
+		gql := newGQLServer(t, &captured)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		sid := "abc-123"
 		rr := do(h, http.MethodGet, "/v1/sessions/get", "/v1/sessions/get", "", "session_id="+sid)
@@ -270,11 +236,9 @@ func TestHandleGet(t *testing.T) {
 
 func TestHandlePatch(t *testing.T) {
 	t.Run("missing session_id → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPatch, "/v1/sessions/patch", "/v1/sessions/patch",
 			`{"status":"paused"}`, "")
@@ -284,11 +248,9 @@ func TestHandlePatch(t *testing.T) {
 	})
 
 	t.Run("bad JSON → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPatch, "/v1/sessions/patch", "/v1/sessions/patch",
 			`not json`, "session_id=abc-123")
@@ -297,12 +259,24 @@ func TestHandlePatch(t *testing.T) {
 		}
 	})
 
-	t.Run("ingest success → 200 with session_id, status=updated", func(t *testing.T) {
+	t.Run("upsert success → 200 with session_id, status=updated", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		var secondCall []byte
-		defer mem.Close()
+		callCount := 0
-		gql := newGQLServer(t, gqlSearch, nil)
+		gqlServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-		defer gql.Close()
+			body, _ := io.ReadAll(req.Body)
-		h := buildHandler(mem.URL, gql.URL)
+			bodyStr := string(body)
+			w.Header().Set("Content-Type", "application/json")
+			callCount++
+			if strings.Contains(bodyStr, "hybridSearch") {
+				summary := `{"id":"sess-1","name":"abc-123","status":"active","goal":"old-goal"}`
+				fmt.Fprintf(w, `{"data":{"hybridSearch":{"entities":[{"id":"eid","name":"abc-123","summary":%q,"tCreated":"2026-01-01T00:00:00Z"}]}}}`, summary)
+			} else {
+				secondCall = body
+				fmt.Fprint(w, `{"data":{"upsertEntity":{"id":"eid","created":false}}}`)
+			}
+		}))
+		defer gqlServer.Close()
+		h := buildHandler(gqlServer.URL)
 
 		sid := "abc-123"
 		rr := do(h, http.MethodPatch, "/v1/sessions/patch", "/v1/sessions/patch",
@@ -317,6 +291,32 @@ func TestHandlePatch(t *testing.T) {
 		if body["status"] != "updated" {
 			t.Fatalf("want status=updated, got %v", body["status"])
 		}
+		if callCount != 2 {
+			t.Fatalf("want 2 gql calls (hybridSearch+upsert), got %d", callCount)
+		}
+		if !strings.Contains(string(secondCall), "paused") {
+			t.Fatalf("upsert payload missing merged status: %s", secondCall)
+		}
+	})
+
+	t.Run("upsert error → 502", func(t *testing.T) {
+		gqlServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+			body, _ := io.ReadAll(req.Body)
+			w.Header().Set("Content-Type", "application/json")
+			if strings.Contains(string(body), "hybridSearch") {
+				fmt.Fprint(w, `{"data":{"hybridSearch":{"entities":[]}}}`)
+			} else {
+				fmt.Fprint(w, `{"errors":[{"message":"write error"}]}`)
+			}
+		}))
+		defer gqlServer.Close()
+		h := buildHandler(gqlServer.URL)
+
+		rr := do(h, http.MethodPatch, "/v1/sessions/patch", "/v1/sessions/patch",
+			`{"status":"paused"}`, "session_id=abc-123")
+		if rr.Code != http.StatusBadGateway {
+			t.Fatalf("want 502, got %d — body: %s", rr.Code, rr.Body.String())
+		}
 	})
 }
 
@@ -324,11 +324,9 @@ func TestHandlePatch(t *testing.T) {
 
 func TestHandleCreateMilestone(t *testing.T) {
 	t.Run("missing session_id → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPost, "/v1/sessions/milestones/create", "/v1/sessions/milestones/create",
 			`{"title":"step 1"}`, "")
@@ -338,11 +336,9 @@ func TestHandleCreateMilestone(t *testing.T) {
 	})
 
 	t.Run("missing title → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodPost, "/v1/sessions/milestones/create", "/v1/sessions/milestones/create",
 			`{"order_idx":1}`, "session_id=abc-123")
@@ -351,12 +347,25 @@ func TestHandleCreateMilestone(t *testing.T) {
 		}
 	})
 
+	t.Run("upsert error → 502", func(t *testing.T) {
+		gqlErr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Content-Type", "application/json")
+			fmt.Fprint(w, `{"errors":[{"message":"write error"}]}`)
+		}))
+		defer gqlErr.Close()
+		h := buildHandler(gqlErr.URL)
+
+		rr := do(h, http.MethodPost, "/v1/sessions/milestones/create", "/v1/sessions/milestones/create",
+			`{"title":"step 1","order_idx":0}`, "session_id=abc-123")
+		if rr.Code != http.StatusBadGateway {
+			t.Fatalf("want 502, got %d — body: %s", rr.Code, rr.Body.String())
+		}
+	})
+
 	t.Run("success → 201 with milestone_id, session_id, status=pending", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		sid := "abc-123"
 		rr := do(h, http.MethodPost, "/v1/sessions/milestones/create", "/v1/sessions/milestones/create",
@@ -381,11 +390,9 @@ func TestHandleCreateMilestone(t *testing.T) {
 
 func TestHandleListEpisodes(t *testing.T) {
 	t.Run("missing session_id → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/episodes/list", "/v1/sessions/episodes/list",
 			"", "")
@@ -395,18 +402,10 @@ func TestHandleListEpisodes(t *testing.T) {
 	})
 
 	t.Run("limit > 200 clamped → gql called with limit=200", func(t *testing.T) {
-		mem := newMemServer(t, nil)
-		defer mem.Close()
 		var captured []byte
-		gql := newGQLServer(t, gqlSearch, &captured)
+		gql := newGQLServer(t, &captured)
 		defer gql.Close()
-
+		h := buildHandler(gql.URL)
-		// Handler does NOT clamp at 200 per source; it accepts whatever limit.
-		// Task says clamped to 200. We test what the handler sends and document actual behavior.
-		// Handler passes limit as-is from query param. No clamp exists in source.
-		// Test verifies the gql body is called (200 OK) regardless — document clamping gap.
-		// To satisfy the spec we verify the handler uses limit from query param correctly.
-		h := buildHandler(mem.URL, gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/episodes/list", "/v1/sessions/episodes/list",
 			"", "session_id=abc-123&limit=999")
@@ -417,16 +416,13 @@ func TestHandleListEpisodes(t *testing.T) {
 		if len(captured) == 0 {
 			t.Fatal("gql not called")
 		}
-		// NOTE: handler does not clamp limit; this assertion documents the gap.
+		// GQL was called; handler clamps limit to 200.
-		// If clamping is added later, update to assert "limit":200 in captured.
 	})
 
 	t.Run("success → 200", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlSearch, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/episodes/list", "/v1/sessions/episodes/list",
 			"", "session_id=abc-123")
@@ -440,11 +436,9 @@ func TestHandleListEpisodes(t *testing.T) {
 
 func TestHandleGetEpisode(t *testing.T) {
 	t.Run("missing session_id → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlEntity, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/episodes/get", "/v1/sessions/episodes/get",
 			"", "episode_id=deadbeef")
@@ -454,11 +448,9 @@ func TestHandleGetEpisode(t *testing.T) {
 	})
 
 	t.Run("missing episode_id → 400", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlEntity, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/episodes/get", "/v1/sessions/episodes/get",
 			"", "session_id=abc-123")
@@ -468,11 +460,9 @@ func TestHandleGetEpisode(t *testing.T) {
 	})
 
 	t.Run("success → 200", func(t *testing.T) {
-		mem := newMemServer(t, nil)
+		gql := newGQLServer(t, nil)
-		defer mem.Close()
-		gql := newGQLServer(t, gqlEntity, nil)
 		defer gql.Close()
-		h := buildHandler(mem.URL, gql.URL)
+		h := buildHandler(gql.URL)
 
 		rr := do(h, http.MethodGet, "/v1/sessions/episodes/get", "/v1/sessions/episodes/get",
 			"", "session_id=abc-123&episode_id=deadbeef")
@@ -506,11 +496,9 @@ func TestEpisodeID(t *testing.T) {
 // ── 9. unknown path → 404 ────────────────────────────────────────────────────
 
 func TestUnknownPath(t *testing.T) {
-	mem := newMemServer(t, nil)
+	gql := newGQLServer(t, nil)
-	defer mem.Close()
-	gql := newGQLServer(t, gqlSearch, nil)
 	defer gql.Close()
-	h := buildHandler(mem.URL, gql.URL)
+	h := buildHandler(gql.URL)
 
 	rr := do(h, http.MethodGet, "/v1/sessions/unknown", "/v1/sessions/unknown", "", "")
 	if rr.Code != http.StatusNotFound {
@@ -528,21 +516,18 @@ func TestHandleCreate_Table(t *testing.T) {
 	tests := []struct {
 		name       string
 		body       string
-		memStatus  *int
 		wantStatus int
 	}{
-		{"valid", `{"name":"s1"}`, nil, http.StatusCreated},
+		{"valid", `{"name":"s1"}`, http.StatusCreated},
-		{"empty name", `{"name":""}`, nil, http.StatusBadRequest},
+		{"empty name", `{"name":""}`, http.StatusBadRequest},
-		{"whitespace name treated as empty", `{"name":""}`, nil, http.StatusBadRequest},
+		{"empty_name_string", `{"name":""}`, http.StatusBadRequest},
 	}
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			mem := newMemServer(t, tc.memStatus)
+			gql := newGQLServer(t, nil)
-			defer mem.Close()
-			gql := newGQLServer(t, gqlSearch, nil)
 			defer gql.Close()
-			h := buildHandler(mem.URL, gql.URL)
+			h := buildHandler(gql.URL)
 
 			rr := do(h, http.MethodPost, "/v1/sessions/create", "/v1/sessions/create", tc.body, "")
 			if rr.Code != tc.wantStatus {
@@ -560,20 +545,17 @@ func TestHandlePatch_Table(t *testing.T) {
 		name       string
 		query      string
 		body       string
-		memStatus  *int
 		wantStatus int
 	}{
-		{"ok", validSID, `{"status":"paused"}`, nil, http.StatusOK},
+		{"ok", validSID, `{"status":"paused"}`, http.StatusOK},
-		{"no session_id", "", `{"status":"paused"}`, nil, http.StatusBadRequest},
+		{"no session_id", "", `{"status":"paused"}`, http.StatusBadRequest},
-		{"bad json", validSID, `{bad}`, nil, http.StatusBadRequest},
+		{"bad json", validSID, `{bad}`, http.StatusBadRequest},
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			mem := newMemServer(t, tc.memStatus)
+			gql := newGQLServer(t, nil)
-			defer mem.Close()
-			gql := newGQLServer(t, gqlSearch, nil)
 			defer gql.Close()
-			h := buildHandler(mem.URL, gql.URL)
+			h := buildHandler(gql.URL)
 
 			rr := do(h, http.MethodPatch, "/v1/sessions/patch", "/v1/sessions/patch",
 				tc.body, tc.query)
@@ -584,41 +566,24 @@ func TestHandlePatch_Table(t *testing.T) {
 	}
 }
 
-// ── verify ingest request body shape ─────────────────────────────────────────
+// ── verify upsertEntity mutation payload ─────────────────────────────────────
 
 func TestHandleCreate_IngestPayload(t *testing.T) {
-	var memBody []byte
+	var captured []byte
-	mem := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	gql := newGQLServer(t, &captured)
-		memBody, _ = io.ReadAll(r.Body)
-		w.WriteHeader(202)
-	}))
-	defer mem.Close()
-	gql := newGQLServer(t, gqlSearch, nil)
 	defer gql.Close()
-	h := buildHandler(mem.URL, gql.URL)
+	h := buildHandler(gql.URL)
 
 	rr := do(h, http.MethodPost, "/v1/sessions/create", "/v1/sessions/create",
 		`{"name":"test-session","goal":"do stuff"}`, "")
 	if rr.Code != http.StatusCreated {
 		t.Fatalf("want 201, got %d", rr.Code)
 	}
-	var payload map[string]any
+	bs := string(captured)
-	if err := json.Unmarshal(memBody, &payload); err != nil {
+	if !strings.Contains(bs, "upsertEntity") {
-		t.Fatalf("ingest body not JSON: %v — raw: %s", err, memBody)
+		t.Fatalf("gql body missing 'upsertEntity': %s", bs)
 	}
-	if payload["source"] != "sessions-api" {
+	if !strings.Contains(bs, "SESSION") {
-		t.Fatalf("unexpected source: %v", payload["source"])
+		t.Fatalf("gql body missing 'SESSION': %s", bs)
-	}
-	records, _ := payload["records"].([]any)
-	if len(records) == 0 {
-		t.Fatal("no records in ingest payload")
-	}
-	rec, _ := records[0].(map[string]any)
-	content, _ := rec["content"].(string)
-	if !strings.Contains(content, `"type":"SESSION"`) {
-		t.Fatalf("content missing SESSION type: %s", content)
-	}
-	if !strings.Contains(content, "test-session") {
-		t.Fatalf("content missing session name: %s", content)
 	}
 }