scrum 2026-04-30: 4 real fixes + 2 INFOs from cross-lineage review

3-lineage scrum (Opus 4.7 / Kimi K2.6 / Qwen3-coder) on today's wave
landed 4 real findings (2 BLOCK + 2 WARN) and 2 INFO touch-ups.
Verbatim verdicts + disposition table at:
  reports/scrum/_evidence/2026-04-30/

B-1 (BLOCK Opus + INFO Kimi convergent) — ResolveKey API:
  collapse from 3-arg (envVar, envFileName, envFilePath) to 2-arg
  (envVar, envFilePath). Pre-fix every chatd caller passed the env
  var name twice; if operator renamed *_key_env in lakehouse.toml
  while keeping the canonical KEY= line in the .env file, fallback
  silently missed.

B-2 (WARN Opus + WARN Kimi convergent) — handleProviders probe:
  drop the synthesize-then-Resolve probe; look up by name directly
  via Registry.Available(name). Prior probe synthesized "<name>/probe"
  model strings and routed through Resolve, fragile to any future
  routing rule (e.g. cloud-suffix special case).

B-3 (BLOCK Opus single — verified by trace + end-to-end probe) —
  OllamaCloud.Chat StripPrefix used "cloud" but registry routes
  "ollama_cloud/<m>". Result: upstream got the prefixed model name
  and 400'd. Smoke missed it because chatd_smoke runs without
  ollama_cloud registered. Now strips the right prefix; new
  TestOllamaCloud_StripsCorrectPrefix locks both prefix + suffix
  cases. Verified live: ollama_cloud/deepseek-v3.2 round-trips
  cleanly through the real ollama.com endpoint.

B-4 (WARN Opus single) — Ollama finishReason: read done_reason
  field instead of inferring from done bool alone. Newer Ollama
  reports done=true with done_reason="length" on truncation; the
  prior code mapped that to "stop" and lost the truncation signal
  the playbook_lift judge needs to retry. New
  TestFinishReasonFromOllama_PrefersDoneReason covers the fallback
  ladder.

INFOs:
- B-5: replace hand-rolled insertion sort in Registry.Names with
  sort.Strings (Opus called the "avoid sort import" comment a
  false economy — correct).
- A-1: clarify the playbook_lift.sh comment around -judge "" arg
  passing (Opus noted the comment said "env priority" but didn't
  reflect that the empty arg also passes through the Go driver's
  resolution chain).

False positives dismissed (3, documented in disposition.md):
- Kimi: TestMaybeDowngrade_WithConfigList wrong assertion (test IS
  correct per design — model excluded from weak list = strong = downgrade)
- Qwen: nil-deref claim (defensive code already handles nil)
- Opus: qwen3.5:latest doesn't exist on Ollama hub (true on the
  public hub but local install has it)

just verify: PASS. chatd_smoke 6/6 PASS. New regression tests:
3 (B-2, B-3, B-4 each get a focused test).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/chat/openai_compat_test.go

@@ -113,6 +113,102 @@ func TestOpenAICompat_EmptyKeyUnavailable(t *testing.T) {
 	}
 }
 
+// TestOllamaCloud_StripsCorrectPrefix locks in scrum fix B-3.
+// Pre-fix: StripPrefix(req.Model, "cloud") never matched "ollama_cloud/<m>"
+// because the prefix string was "cloud/" not "ollama_cloud/". Result was
+// the upstream got the prefixed model name and 400'd. This test would
+// have caught it had it existed.
+func TestOllamaCloud_StripsCorrectPrefix(t *testing.T) {
+	captured := ""
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		bs, _ := io.ReadAll(r.Body)
+		captured = string(bs)
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(200)
+		_, _ = w.Write([]byte(`{"model":"deepseek-v3.2","response":"ok","done":true,"done_reason":"stop"}`))
+	}))
+	t.Cleanup(srv.Close)
+
+	// Inject the test server URL via reflection-free constructor —
+	// just build the struct directly with our overrides since
+	// NewOllamaCloud hardcodes ollama.com.
+	o := &OllamaCloud{
+		apiKey:     "test-key",
+		baseURL:    srv.URL,
+		httpClient: srv.Client(),
+	}
+
+	cases := []struct {
+		input    string
+		expected string // model the upstream should see
+	}{
+		// Prefix form (Phase 4 scrum fix B-3): strip "ollama_cloud/"
+		{"ollama_cloud/deepseek-v3.2", "deepseek-v3.2"},
+		{"ollama_cloud/kimi-k2.6:cloud", "kimi-k2.6:cloud"},
+		// Suffix form: nothing to strip (already canonical)
+		{"kimi-k2.6:cloud", "kimi-k2.6:cloud"},
+		{"qwen3-coder:480b", "qwen3-coder:480b"},
+	}
+	for _, c := range cases {
+		captured = ""
+		_, err := o.Chat(context.Background(), Request{
+			Model:    c.input,
+			Messages: []Message{{Role: "user", Content: "hi"}},
+		})
+		if err != nil {
+			t.Errorf("Chat(%q): %v", c.input, err)
+			continue
+		}
+		var sent map[string]any
+		if err := json.Unmarshal([]byte(captured), &sent); err != nil {
+			t.Fatalf("parse captured: %v", err)
+		}
+		got, _ := sent["model"].(string)
+		if got != c.expected {
+			t.Errorf("Chat(%q): upstream got model=%q, want %q", c.input, got, c.expected)
+		}
+	}
+}
+
+func TestFinishReasonFromOllama_PrefersDoneReason(t *testing.T) {
+	// Phase 4 scrum fix B-4: done_reason takes precedence when present.
+	cases := []struct {
+		done       bool
+		doneReason string
+		want       string
+	}{
+		{true, "stop", "stop"},
+		{true, "length", "length"}, // truncation surfaced — pre-fix lost this
+		{true, "", "stop"},          // legacy fallback
+		{false, "", "length"},
+		{false, "stop", "stop"}, // done_reason wins regardless of done
+	}
+	for _, c := range cases {
+		got := finishReasonFromOllama(c.done, c.doneReason)
+		if got != c.want {
+			t.Errorf("finishReasonFromOllama(%v, %q) = %q, want %q", c.done, c.doneReason, got, c.want)
+		}
+	}
+}
+
+func TestRegistry_AvailableLooksUpDirectly(t *testing.T) {
+	// Phase 4 scrum fix B-2: Available() reports registry membership,
+	// not routing. Unregistered name → false; registered + Available()
+	// → true; registered but empty key → false.
+	registered := newFake("openrouter", true)
+	disabled := newFake("opencode", false) // "registered" but no key
+	r := NewRegistry(registered, disabled)
+	if !r.Available("openrouter") {
+		t.Errorf("openrouter should be Available")
+	}
+	if r.Available("opencode") {
+		t.Errorf("opencode has no key — Available should be false")
+	}
+	if r.Available("nonexistent") {
+		t.Errorf("nonexistent should be false")
+	}
+}
+
 func TestNewProviderConstructors(t *testing.T) {
 	// Smoke: each public constructor produces a working provider with
 	// the right name/prefix and respects empty-key=unavailable.