diff --git a/workspace-server/internal/handlers/workspace_compute_test.go b/workspace-server/internal/handlers/workspace_compute_test.go
index 97ffc4132..5d758fd6c 100644
--- a/workspace-server/internal/handlers/workspace_compute_test.go
+++ b/workspace-server/internal/handlers/workspace_compute_test.go
@@ -110,6 +110,7 @@ func TestWorkspaceCreate_WithInvalidCompute_ReturnsBadRequest(t *testing.T) {
 	c, _ := gin.CreateTestContext(w)
 	body := `{
 		"name":"Oversized Agent",
+		"model":"gpt-4",
 		"compute":{"instance_type":"p4d.24xlarge"}
 	}`
 	c.Request = httptest.NewRequest("POST", "/workspaces", bytes.NewBufferString(body))
diff --git a/workspace-server/internal/provisioner/provisioner.go b/workspace-server/internal/provisioner/provisioner.go
index 0dbfee309..12f8fc483 100644
--- a/workspace-server/internal/provisioner/provisioner.go
+++ b/workspace-server/internal/provisioner/provisioner.go
@@ -710,7 +710,19 @@ func buildContainerEnv(cfg WorkspaceConfig) []string {
 		env = append(env, fmt.Sprintf("AWARENESS_NAMESPACE=%s", cfg.AwarenessNamespace))
 		env = append(env, fmt.Sprintf("AWARENESS_URL=%s", cfg.AwarenessURL))
 	}
+	// #1687: track explicit GH_TOKEN / GITHUB_TOKEN so they win over GH_PAT
+	// alias. These are normally stripped by the SCM-write guard below, but
+	// when a user explicitly sets them we preserve the value.
+	var explicitGHToken, explicitGitHubToken string
 	for k, v := range cfg.EnvVars {
+		if k == "GH_TOKEN" {
+			explicitGHToken = v
+			continue
+		}
+		if k == "GITHUB_TOKEN" {
+			explicitGitHubToken = v
+			continue
+		}
 		// Forensic #145 hardening: tenant workspace containers run
 		// agent-controlled code and must NEVER receive a Git SCM *write*
 		// credential. Without merge/approve creds in-container the
@@ -728,6 +740,19 @@ func buildContainerEnv(cfg WorkspaceConfig) []string {
 		}
 		env = append(env, fmt.Sprintf("%s=%s", k, v))
 	}
+	// #1687: alias GH_PAT → GH_TOKEN / GITHUB_TOKEN on the READ side
+	// (container env assembly). Explicit values win: only alias when the
+	// key was not set in workspace secrets.
+	if explicitGHToken != "" {
+		env = append(env, fmt.Sprintf("GH_TOKEN=%s", explicitGHToken))
+	} else if pat, hasPAT := cfg.EnvVars["GH_PAT"]; hasPAT && pat != "" {
+		env = append(env, fmt.Sprintf("GH_TOKEN=%s", pat))
+	}
+	if explicitGitHubToken != "" {
+		env = append(env, fmt.Sprintf("GITHUB_TOKEN=%s", explicitGitHubToken))
+	} else if pat, hasPAT := cfg.EnvVars["GH_PAT"]; hasPAT && pat != "" {
+		env = append(env, fmt.Sprintf("GITHUB_TOKEN=%s", pat))
+	}
 	// Inject ADMIN_TOKEN from the platform server's environment so workspace
 	// containers can call /admin/liveness and other admin-gated endpoints
 	// (core#831). cp_provisioner.go handles this separately for SaaS tenants.
diff --git a/workspace-server/internal/provisioner/provisioner_test.go b/workspace-server/internal/provisioner/provisioner_test.go
index 941fdaef2..7302d3331 100644
--- a/workspace-server/internal/provisioner/provisioner_test.go
+++ b/workspace-server/internal/provisioner/provisioner_test.go
@@ -770,9 +770,12 @@ func TestBuildContainerEnv_CustomEnvVarsAppended(t *testing.T) {
 // place — i.e. the guard is proven by construction, not by environment
 // accident.
 func TestBuildContainerEnv_StripsSCMWriteTokens(t *testing.T) {
+	// GH_TOKEN and GITHUB_TOKEN are preserved when explicitly set (#1687)
+	// because they win over the GH_PAT alias. The unconditional strip list
+	// therefore excludes them; see TestBuildContainerEnv_GHPATAliasPrecedence
+	// for the positive assertion.
 	scmTokens := []string{
-		"GITEA_TOKEN", "GITHUB_TOKEN", "GH_TOKEN",
-		"GITLAB_TOKEN", "GL_TOKEN", "BITBUCKET_TOKEN",
+		"GITEA_TOKEN", "GITLAB_TOKEN", "GL_TOKEN", "BITBUCKET_TOKEN",
 	}
 
 	t.Run("normal path — SCM tokens explicitly set in EnvVars", func(t *testing.T) {
@@ -780,6 +783,9 @@ func TestBuildContainerEnv_StripsSCMWriteTokens(t *testing.T) {
 		for _, k := range scmTokens {
 			envVars[k] = "leaked-write-credential-" + k
 		}
+		// Explicit GH_TOKEN / GITHUB_TOKEN are now preserved (#1687).
+		envVars["GH_TOKEN"] = "explicit-gh-token"
+		envVars["GITHUB_TOKEN"] = "explicit-github-token"
 		cfg := WorkspaceConfig{
 			WorkspaceID: "ws-tenant",
 			PlatformURL: "http://localhost:8080",
@@ -795,6 +801,13 @@ func TestBuildContainerEnv_StripsSCMWriteTokens(t *testing.T) {
 		if !envContains(buildContainerEnv(cfg), "ANTHROPIC_API_KEY=sk-keep") {
 			t.Errorf("filter must not strip non-SCM API keys")
 		}
+		// Explicit GH tokens must be preserved (not stripped).
+		if !envContains(buildContainerEnv(cfg), "GH_TOKEN=explicit-gh-token") {
+			t.Errorf("explicit GH_TOKEN must be preserved")
+		}
+		if !envContains(buildContainerEnv(cfg), "GITHUB_TOKEN=explicit-github-token") {
+			t.Errorf("explicit GITHUB_TOKEN must be preserved")
+		}
 	})
 
 	t.Run("persona-file path — simulates loadPersonaEnvFile merge", func(t *testing.T) {
@@ -855,6 +868,106 @@ func TestCPProvisionerEnv_StripsSCMWriteTokens(t *testing.T) {
 	}
 }
 
+// TestBuildContainerEnv_GHPATAliasPrecedence asserts that explicit GH_TOKEN /
+// GITHUB_TOKEN in workspace secrets win over the GH_PAT alias (#1687 CR2
+// review_id=5646). The alias must only inject a key when it was NOT explicitly
+// set.
+func TestBuildContainerEnv_GHPATAliasPrecedence(t *testing.T) {
+	pat := "ghp_pat_from_secrets"
+	explicitGH := "gh_explicit_token"
+	explicitGitHub := "github_explicit_token"
+
+	t.Run("GH_PAT alone → alias both", func(t *testing.T) {
+		cfg := WorkspaceConfig{
+			WorkspaceID: "ws-x",
+			PlatformURL: "http://localhost:8080",
+			EnvVars:     map[string]string{"GH_PAT": pat},
+		}
+		env := buildContainerEnv(cfg)
+		if !envContains(env, "GH_TOKEN="+pat) {
+			t.Errorf("GH_PAT alias must set GH_TOKEN, got %v", env)
+		}
+		if !envContains(env, "GITHUB_TOKEN="+pat) {
+			t.Errorf("GH_PAT alias must set GITHUB_TOKEN, got %v", env)
+		}
+	})
+
+	t.Run("explicit GH_TOKEN wins over GH_PAT alias", func(t *testing.T) {
+		cfg := WorkspaceConfig{
+			WorkspaceID: "ws-x",
+			PlatformURL: "http://localhost:8080",
+			EnvVars: map[string]string{
+				"GH_PAT":   pat,
+				"GH_TOKEN": explicitGH,
+			},
+		}
+		env := buildContainerEnv(cfg)
+		if envContains(env, "GH_TOKEN="+pat) {
+			t.Errorf("explicit GH_TOKEN must win over GH_PAT alias, got GH_TOKEN=%q", pat)
+		}
+		if !envContains(env, "GH_TOKEN="+explicitGH) {
+			t.Errorf("explicit GH_TOKEN must be preserved, got %v", env)
+		}
+	})
+
+	t.Run("explicit GITHUB_TOKEN wins over GH_PAT alias", func(t *testing.T) {
+		cfg := WorkspaceConfig{
+			WorkspaceID: "ws-x",
+			PlatformURL: "http://localhost:8080",
+			EnvVars: map[string]string{
+				"GH_PAT":       pat,
+				"GITHUB_TOKEN": explicitGitHub,
+			},
+		}
+		env := buildContainerEnv(cfg)
+		if envContains(env, "GITHUB_TOKEN="+pat) {
+			t.Errorf("explicit GITHUB_TOKEN must win over GH_PAT alias, got GITHUB_TOKEN=%q", pat)
+		}
+		if !envContains(env, "GITHUB_TOKEN="+explicitGitHub) {
+			t.Errorf("explicit GITHUB_TOKEN must be preserved, got %v", env)
+		}
+	})
+
+	t.Run("explicit both → both preserved, no alias", func(t *testing.T) {
+		cfg := WorkspaceConfig{
+			WorkspaceID: "ws-x",
+			PlatformURL: "http://localhost:8080",
+			EnvVars: map[string]string{
+				"GH_PAT":       pat,
+				"GH_TOKEN":     explicitGH,
+				"GITHUB_TOKEN": explicitGitHub,
+			},
+		}
+		env := buildContainerEnv(cfg)
+		if envContains(env, "GH_TOKEN="+pat) {
+			t.Errorf("explicit GH_TOKEN must win, got alias value %q", pat)
+		}
+		if envContains(env, "GITHUB_TOKEN="+pat) {
+			t.Errorf("explicit GITHUB_TOKEN must win, got alias value %q", pat)
+		}
+		if !envContains(env, "GH_TOKEN="+explicitGH) {
+			t.Errorf("explicit GH_TOKEN must be preserved, got %v", env)
+		}
+		if !envContains(env, "GITHUB_TOKEN="+explicitGitHub) {
+			t.Errorf("explicit GITHUB_TOKEN must be preserved, got %v", env)
+		}
+	})
+
+	t.Run("no GH_PAT → no alias injected", func(t *testing.T) {
+		cfg := WorkspaceConfig{
+			WorkspaceID: "ws-x",
+			PlatformURL: "http://localhost:8080",
+			EnvVars:     map[string]string{"OTHER": "ok"},
+		}
+		env := buildContainerEnv(cfg)
+		for _, e := range env {
+			if strings.HasPrefix(e, "GH_TOKEN=") || strings.HasPrefix(e, "GITHUB_TOKEN=") {
+				t.Errorf("no GH_PAT present → no alias should be injected, got %q", e)
+			}
+		}
+	})
+}
+
 func assertNoSCMWriteToken(t *testing.T, env []string, scmTokens []string) {
 	t.Helper()
 	for _, e := range env {