diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c2673b40..ba289fec 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,6 +25,7 @@ on:
 env:
     LUA_VERSION: 5.4.7
     LUAROCKS_VERSION: 3.9.0
+    PT_VERSION: 0.5.0a
 
 jobs:
     lint:
@@ -79,7 +80,7 @@ jobs:
 
             - name: Install Pallene Tracer
               run: |
-                  git clone https://github.com/pallene-lang/pallene-tracer
+                  git clone --depth 1 https://github.com/pallene-lang/pallene-tracer --branch ${{env.PT_VERSION}}
                   cd pallene-tracer
                   make LUA_PREFIX=/usr/local
                   sudo make install
diff --git a/spec/traceback_spec.lua b/spec/traceback_spec.lua
index f0ce4366..316e66ef 100644
--- a/spec/traceback_spec.lua
+++ b/spec/traceback_spec.lua
@@ -19,25 +19,26 @@ local function assert_test(test, expected_traceback)
     end
 
     local luafile = util.shell_quote("spec/traceback/"..test.."/main.lua")
-    local ok, _, output_content, err_content = util.outputs_of_execute("pt-run "..luafile)
+    local ok, _, output_content, err_content = util.outputs_of_execute("pt-lua "..luafile)
     assert(not ok, output_content)
     assert.are.same(expected_traceback, err_content)
 end
 
 it("Rectangle", function()
     assert_test("rect", [[
-Runtime error: spec/traceback/rect/main.lua:8: file spec/traceback/rect/rect.pln: line 10: wrong type for downcasted value, expected float but found string
-Stack traceback:
+pt-lua: spec/traceback/rect/main.lua:8: file spec/traceback/rect/rect.pln: line 10: wrong type for downcasted value, expected float but found string
+stack traceback:
     spec/traceback/rect/rect.pln:10: in function 'universal_calc_area'
     spec/traceback/rect/rect.pln:13: in function 'area'
     spec/traceback/rect/main.lua:8: in <main>
+    C: in function '<?>'
 ]])
 end)
 
 it("Multi-module Lua", function()
     assert_test("module_lua", [[
-Runtime error: spec/traceback/module_lua/main.lua:25: Any normal error from Lua!
-Stack traceback:
+pt-lua: spec/traceback/module_lua/main.lua:25: Any normal error from Lua!
+stack traceback:
     C: in function 'error'
     spec/traceback/module_lua/main.lua:25: in function 'lua_3'
     spec/traceback/module_lua/module_lua.pln:12: in function 'pallene_2'
@@ -46,26 +47,28 @@ Stack traceback:
     spec/traceback/module_lua/main.lua:12: in function 'callback'
     ./spec/traceback/module_lua/another_module.lua:7: in function 'call_lua_callback'
     spec/traceback/module_lua/main.lua:28: in <main>
+    C: in function '<?>'
 ]])
 end)
 
 it("Multi-module Pallene", function()
     assert_test("module_pallene", [[
-Runtime error: spec/traceback/module_pallene/main.lua:11: There's an error in everyday life. Alas!
-Stack traceback:
+pt-lua: spec/traceback/module_pallene/main.lua:11: There's an error in everyday life. Alas!
+stack traceback:
     C: in function 'error'
     spec/traceback/module_pallene/main.lua:11: in function 'lua_2'
     spec/traceback/module_pallene/module_pallene_alt.pln:8: in function 'alternate_everyday_fn'
     spec/traceback/module_pallene/main.lua:16: in function 'lua_1'
     spec/traceback/module_pallene/module_pallene.pln:8: in function 'normal_everyday_fn'
     spec/traceback/module_pallene/main.lua:19: in <main>
+    C: in function '<?>'
 ]])
 end)
 
 it("Depth recursion", function()
     assert_test("depth_recursion", [[
-Runtime error: spec/traceback/depth_recursion/main.lua:11: Depth reached 0!
-Stack traceback:
+pt-lua: spec/traceback/depth_recursion/main.lua:11: Depth reached 0!
+stack traceback:
     C: in function 'error'
     spec/traceback/depth_recursion/main.lua:11: in function 'lua_fn'
     spec/traceback/depth_recursion/depth_recursion.pln:8: in function 'pallene_fn'
@@ -79,13 +82,14 @@ Stack traceback:
     spec/traceback/depth_recursion/depth_recursion.pln:8: in function 'pallene_fn'
     spec/traceback/depth_recursion/main.lua:14: in function 'lua_fn'
     spec/traceback/depth_recursion/main.lua:17: in <main>
+    C: in function '<?>'
 ]])
 end)
 
 it("Stack overflow", function()
     assert_test("stack_overflow", [[
-Runtime error: C stack overflow
-Stack traceback:
+pt-lua: C stack overflow
+stack traceback:
     spec/traceback/stack_overflow/stack_overflow.pln:8: in function 'no_overflow'
     spec/traceback/stack_overflow/main.lua:10: in function 'please_dont_overflow'
     spec/traceback/stack_overflow/stack_overflow.pln:8: in function 'no_overflow'
@@ -97,9 +101,8 @@ Stack traceback:
     spec/traceback/stack_overflow/stack_overflow.pln:8: in function 'no_overflow'
     spec/traceback/stack_overflow/main.lua:10: in function 'please_dont_overflow'
 
-    ... (Skipped 380 frames) ...
+    ... (Skipped 379 frames) ...
 
-    spec/traceback/stack_overflow/main.lua:10: in function 'please_dont_overflow'
     spec/traceback/stack_overflow/stack_overflow.pln:8: in function 'no_overflow'
     spec/traceback/stack_overflow/main.lua:10: in function 'please_dont_overflow'
     spec/traceback/stack_overflow/stack_overflow.pln:8: in function 'no_overflow'
@@ -109,16 +112,18 @@ Stack traceback:
     spec/traceback/stack_overflow/stack_overflow.pln:8: in function 'no_overflow'
     spec/traceback/stack_overflow/main.lua:10: in function 'please_dont_overflow'
     spec/traceback/stack_overflow/main.lua:13: in <main>
+    C: in function '<?>'
 ]])
 end)
 
 it("Anonymous lua functions", function()
     assert_test("anon_lua", [[
-Runtime error: spec/traceback/anon_lua/main.lua:9: Error from an anonymous Lua fn!
-Stack traceback:
+pt-lua: spec/traceback/anon_lua/main.lua:9: Error from an anonymous Lua fn!
+stack traceback:
     C: in function 'error'
     spec/traceback/anon_lua/main.lua:9: in function '<?>'
     spec/traceback/anon_lua/anon_lua.pln:8: in function 'call_anon_lua_fn'
     spec/traceback/anon_lua/main.lua:8: in <main>
+    C: in function '<?>'
 ]])
 end)