diff --git a/workspace-server/internal/handlers/delegation_test.go b/workspace-server/internal/handlers/delegation_test.go
index 427e71b2..38c63206 100644
--- a/workspace-server/internal/handlers/delegation_test.go
+++ b/workspace-server/internal/handlers/delegation_test.go
@@ -1262,4 +1262,3 @@ func TestExecuteDelegation_CleanProxyResponse_Unchanged(t *testing.T) {
 		t.Errorf("unmet sqlmock expectations: %v", err)
 	}
 }
-}
diff --git a/workspace-server/internal/handlers/workspace_provision.go b/workspace-server/internal/handlers/workspace_provision.go
index 57d6c5a6..bf910ff4 100644
--- a/workspace-server/internal/handlers/workspace_provision.go
+++ b/workspace-server/internal/handlers/workspace_provision.go
@@ -717,13 +717,16 @@ func deriveProviderFromModelSlug(model string) string {
 func applyRuntimeModelEnv(envVars map[string]string, runtime, model string) {
 	// Resolution order (priority high → low):
 	//   1. payload.Model (caller passed the canvas-picked model id verbatim)
-	//   2. envVars["MODEL"]  (workspace_secret persisted by /org/import via
+	//   2. envVars["MOLECULE_MODEL"]  (the canonical, unambiguous name)
+	//   3. envVars["MODEL"]  (workspace_secret persisted by /org/import via
 	//      the persona env file — MODEL=MiniMax-M2.7-highspeed etc.)
-	//   3. envVars["MODEL_PROVIDER"] (legacy: this secret was historically a
-	//      *model id* set by canvas Save+Restart's PUT /model; on the
-	//      post-2026-05-08 persona-env convention it's a *provider slug*
-	//      (e.g. "minimax") which is NOT a valid model id, so this fallback
-	//      only fires when MODEL is absent.)
+	//   4. envVars["MODEL_PROVIDER"] (legacy + misleadingly named: it carries
+	//      a *model id*, never the provider — that's LLM_PROVIDER. Historically
+	//      set by canvas Save+Restart's PUT /model; the post-2026-05-08
+	//      persona-env convention sometimes (mis)set it to a provider slug
+	//      ("minimax") or a runtime name ("claude-code"), neither a valid
+	//      model id — see internal#226. Only fires when the better-named
+	//      vars are absent.)
 	//
 	// Pre-fix bug: this function unconditionally OVERWROTE envVars["MODEL"]
 	// with the MODEL_PROVIDER slug (when payload.Model was empty), wiping
@@ -736,6 +739,9 @@ func applyRuntimeModelEnv(envVars map[string]string, runtime, model string) {
 	// and the workspace template's adapter routed to providers[0]
 	// (anthropic-oauth) and wedged at SDK initialize. Caught 2026-05-08
 	// during Phase 4 verification of template-claude-code PR #9.
+	if model == "" {
+		model = envVars["MOLECULE_MODEL"]
+	}
 	if model == "" {
 		model = envVars["MODEL"]
 	}
@@ -746,16 +752,18 @@ func applyRuntimeModelEnv(envVars map[string]string, runtime, model string) {
 		return
 	}
 
-	// Universal MODEL env var — every adapter that wants to honour the
-	// canvas-picked model (instead of its template's default) reads this.
-	// molecule-runtime's workspace/config.py already falls back to MODEL
-	// for runtime_config.model (#194). Without this line, the user's
-	// canvas selection is silently dropped on every templated provision —
-	// confirmed via crash-loop diagnosis on 2026-05-02 where MiniMax
-	// picks booted with model=sonnet (template default) and demanded
-	// CLAUDE_CODE_OAUTH_TOKEN. Set it FIRST so the per-runtime branches
-	// below can still layer on additional vendor-specific names without
-	// fighting over the canonical one.
+	// Canonical model env vars — molecule-runtime's workspace/config.py
+	// resolves the picked model as MOLECULE_MODEL > MODEL > (legacy)
+	// MODEL_PROVIDER (#280). Export both new names so adapters can read
+	// either; MODEL stays for backwards compat with everything that
+	// already reads os.environ["MODEL"] (the claude-code adapter does,
+	// since #194). Without this, the user's canvas selection is silently
+	// dropped on every templated provision — confirmed via crash-loop
+	// diagnosis on 2026-05-02 where MiniMax picks booted with model=sonnet
+	// (template default) and demanded CLAUDE_CODE_OAUTH_TOKEN. Set these
+	// FIRST so the per-runtime branches below can layer on additional
+	// vendor-specific names without fighting over the canonical one.
+	envVars["MOLECULE_MODEL"] = model
 	envVars["MODEL"] = model
 
 	switch runtime {
diff --git a/workspace-server/internal/handlers/workspace_provision_shared_test.go b/workspace-server/internal/handlers/workspace_provision_shared_test.go
index 7a85d118..01101ddf 100644
--- a/workspace-server/internal/handlers/workspace_provision_shared_test.go
+++ b/workspace-server/internal/handlers/workspace_provision_shared_test.go
@@ -665,46 +665,62 @@ func TestApplyRuntimeModelEnv_SetsUniversalMODELForAllRuntimes(t *testing.T) {
 		runtime           string
 		model             string
 		modelProviderEnv  string
+		moleculeModelEnv  string
 		wantMODEL         string
 		wantHermesDefault string // empty string = must be unset
 	}{
 		{
-			name:      "claude-code: picked model populates MODEL",
+			name:      "claude-code: picked model populates MODEL + MOLECULE_MODEL",
 			runtime:   "claude-code",
 			model:     "MiniMax-M2",
 			wantMODEL: "MiniMax-M2",
 		},
 		{
-			name:              "hermes: picked model populates BOTH MODEL and HERMES_DEFAULT_MODEL",
+			name:              "hermes: picked model populates MODEL, MOLECULE_MODEL, HERMES_DEFAULT_MODEL",
 			runtime:           "hermes",
 			model:             "minimax/MiniMax-M2.7",
 			wantMODEL:         "minimax/MiniMax-M2.7",
 			wantHermesDefault: "minimax/MiniMax-M2.7",
 		},
 		{
-			name:      "langgraph: picked model populates MODEL (no vendor-specific name)",
+			name:      "langgraph: picked model populates MODEL + MOLECULE_MODEL (no vendor-specific name)",
 			runtime:   "langgraph",
 			model:     "anthropic:claude-opus-4-7",
 			wantMODEL: "anthropic:claude-opus-4-7",
 		},
 		{
-			name:      "crewai: picked model populates MODEL (no vendor-specific name)",
+			name:      "crewai: picked model populates MODEL + MOLECULE_MODEL (no vendor-specific name)",
 			runtime:   "crewai",
 			model:     "openai:gpt-4o",
 			wantMODEL: "openai:gpt-4o",
 		},
 		{
-			name:    "empty model + empty MODEL_PROVIDER fallback: nothing set",
+			name:    "empty model + no env fallback: nothing set",
 			runtime: "claude-code",
 			model:   "",
 		},
 		{
-			name:             "empty model + MODEL_PROVIDER fallback hits: MODEL set from secret",
+			name:             "empty model + MODEL_PROVIDER fallback hits: MODEL/MOLECULE_MODEL set from secret",
 			runtime:          "claude-code",
 			model:            "",
 			modelProviderEnv: "MiniMax-M2",
 			wantMODEL:        "MiniMax-M2",
 		},
+		{
+			name:             "empty model + MOLECULE_MODEL env fallback hits (canonical name)",
+			runtime:          "claude-code",
+			model:            "",
+			moleculeModelEnv: "opus",
+			wantMODEL:        "opus",
+		},
+		{
+			name:             "MOLECULE_MODEL beats MODEL_PROVIDER when both set (misnomer guard, internal#226)",
+			runtime:          "claude-code",
+			model:            "",
+			moleculeModelEnv: "opus",
+			modelProviderEnv: "claude-code",
+			wantMODEL:        "opus",
+		},
 	}
 
 	for _, tc := range cases {
@@ -713,11 +729,18 @@ func TestApplyRuntimeModelEnv_SetsUniversalMODELForAllRuntimes(t *testing.T) {
 			if tc.modelProviderEnv != "" {
 				envVars["MODEL_PROVIDER"] = tc.modelProviderEnv
 			}
+			if tc.moleculeModelEnv != "" {
+				envVars["MOLECULE_MODEL"] = tc.moleculeModelEnv
+			}
 			applyRuntimeModelEnv(envVars, tc.runtime, tc.model)
 
 			if got := envVars["MODEL"]; got != tc.wantMODEL {
 				t.Errorf("MODEL = %q, want %q", got, tc.wantMODEL)
 			}
+			// MOLECULE_MODEL (the canonical name) must mirror MODEL exactly.
+			if got := envVars["MOLECULE_MODEL"]; got != tc.wantMODEL {
+				t.Errorf("MOLECULE_MODEL = %q, want %q", got, tc.wantMODEL)
+			}
 			if got := envVars["HERMES_DEFAULT_MODEL"]; got != tc.wantHermesDefault {
 				t.Errorf("HERMES_DEFAULT_MODEL = %q, want %q", got, tc.wantHermesDefault)
 			}