diff --git a/lua/test-samurai/config.lua b/lua/test-samurai/config.lua
index d3538cb..e13eddd 100644
--- a/lua/test-samurai/config.lua
+++ b/lua/test-samurai/config.lua
@@ -6,7 +6,6 @@ local defaults = {
     "test-samurai.runners.js-jest",
     "test-samurai.runners.js-mocha",
     "test-samurai.runners.js-vitest",
-    "test-samurai.runners.lua-plenary",
   },
 }
 
diff --git a/lua/test-samurai/core.lua b/lua/test-samurai/core.lua
index d8b02bc..4dec1a6 100644
--- a/lua/test-samurai/core.lua
+++ b/lua/test-samurai/core.lua
@@ -8,6 +8,11 @@ local state = {
   last_win = nil,
   last_buf = nil,
   last_command = nil,
+  last_scope_command = nil,
+  last_scope_runner = nil,
+  last_scope_kind = nil,
+  last_scope_exit_code = nil,
+  last_scope_failures = nil,
   autocmds_set = false,
 }
 
@@ -52,6 +57,11 @@ function M.setup()
   load_runners()
   ensure_output_autocmds()
   state.last_command = nil
+  state.last_scope_command = nil
+  state.last_scope_runner = nil
+  state.last_scope_kind = nil
+  state.last_scope_exit_code = nil
+  state.last_scope_failures = nil
 end
 
 function M.reload_runners()
@@ -299,12 +309,45 @@ local function run_cmd(cmd, cwd, handlers)
   })
 end
 
-local function run_command(command)
+local function format_results(results)
+  local lines = {}
+  if type(results.passes) == "table" then
+    for _, title in ipairs(results.passes) do
+      table.insert(lines, "[ PASS ] - " .. title)
+    end
+  end
+  if type(results.skips) == "table" then
+    for _, title in ipairs(results.skips) do
+      table.insert(lines, "[ SKIP ] - " .. title)
+    end
+  end
+  if type(results.failures) == "table" then
+    for _, title in ipairs(results.failures) do
+      table.insert(lines, "[ FAIL ] - " .. title)
+    end
+  end
+  return lines
+end
+
+local function run_command(command, opts)
+  local options = opts or {}
   if command and type(command.cmd) == "table" and #command.cmd > 0 then
-    state.last_command = {
-      cmd = vim.deepcopy(command.cmd),
-      cwd = command.cwd,
-    }
+    if options.save_last ~= false then
+      state.last_command = {
+        cmd = vim.deepcopy(command.cmd),
+        cwd = command.cwd,
+      }
+    end
+    if options.track_scope then
+      state.last_scope_command = {
+        cmd = vim.deepcopy(command.cmd),
+        cwd = command.cwd,
+      }
+      state.last_scope_runner = options.runner
+      state.last_scope_kind = options.scope_kind
+      state.last_scope_exit_code = nil
+      state.last_scope_failures = nil
+    end
   end
   local cmd = command.cmd
   local cwd = command.cwd or vim.loop.cwd()
@@ -312,48 +355,126 @@ local function run_command(command)
   local header = "$ " .. table.concat(cmd, " ")
   local buf = nil
   local has_output = false
+  local parser = options.output_parser
+  if type(parser) == "function" then
+    parser = { on_complete = parser }
+  end
+  local parser_state = {}
+  local had_parsed_output = false
+
+  local output_lines = {}
+
+  local function collect_output(lines)
+    if not lines or #lines == 0 then
+      return
+    end
+    for _, line in ipairs(lines) do
+      if line ~= nil then
+        table.insert(output_lines, line)
+      end
+    end
+  end
+
+  local function ensure_output_started()
+    if not buf then
+      buf = select(1, create_output_win({ header, "" }))
+    end
+    if not has_output then
+      local cur = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
+      if #cur > 0 and cur[#cur] == "[running...]" then
+        vim.api.nvim_buf_set_lines(buf, #cur - 1, #cur, false, {})
+      end
+      has_output = true
+    end
+  end
+
+  local function handle_parsed(results)
+    if not results then
+      return
+    end
+    local lines = format_results(results)
+    if #lines == 0 then
+      return
+    end
+    ensure_output_started()
+    append_lines(buf, lines)
+    had_parsed_output = true
+    if options.track_scope then
+      if results.failures_all ~= nil then
+        state.last_scope_failures = results.failures_all
+      elseif results.failures ~= nil then
+        state.last_scope_failures = results.failures
+      end
+    end
+  end
 
   run_cmd(cmd, cwd, {
     on_start = function()
       buf = select(1, create_output_win({ header, "", "[running...]" }))
     end,
     on_stdout = function(lines)
-      if not buf then
-        buf = select(1, create_output_win({ header, "" }))
-      end
-      if not has_output then
-        local cur = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
-        if #cur > 0 and cur[#cur] == "[running...]" then
-          vim.api.nvim_buf_set_lines(buf, #cur - 1, #cur, false, {})
+      if parser then
+        collect_output(lines)
+        if parser.on_line then
+          for _, line in ipairs(lines or {}) do
+            local ok_parse, results = pcall(parser.on_line, line, parser_state)
+            if ok_parse then
+              handle_parsed(results)
+            end
+          end
         end
-        has_output = true
+        return
       end
+      ensure_output_started()
       append_lines(buf, lines)
     end,
     on_stderr = function(lines)
-      if not buf then
-        buf = select(1, create_output_win({ header, "" }))
-      end
-      if not has_output then
-        local cur = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
-        if #cur > 0 and cur[#cur] == "[running...]" then
-          vim.api.nvim_buf_set_lines(buf, #cur - 1, #cur, false, {})
+      if parser then
+        collect_output(lines)
+        if parser.on_line then
+          for _, line in ipairs(lines or {}) do
+            local ok_parse, results = pcall(parser.on_line, line, parser_state)
+            if ok_parse then
+              handle_parsed(results)
+            end
+          end
         end
-        has_output = true
+        return
       end
+      ensure_output_started()
       append_lines(buf, lines)
     end,
     on_exit = function(code)
       if not buf then
         buf = select(1, create_output_win({ header }))
       end
-      if not has_output then
-        local cur = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
-        if #cur > 0 and cur[#cur] == "[running...]" then
-          vim.api.nvim_buf_set_lines(buf, #cur - 1, #cur, false, {})
+      if parser and parser.on_complete then
+        local output = table.concat(output_lines, "\n")
+        local ok_parse, results = pcall(parser.on_complete, output, parser_state)
+        if ok_parse then
+          handle_parsed(results)
         end
       end
-      append_lines(buf, { "", "[exit code] " .. tostring(code) })
+      if parser then
+        if not had_parsed_output and #output_lines > 0 then
+          ensure_output_started()
+          append_lines(buf, output_lines)
+        elseif not has_output then
+          ensure_output_started()
+        end
+        append_lines(buf, { "", "[exit code] " .. tostring(code) })
+      else
+        if not has_output then
+          local cur = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
+          if #cur > 0 and cur[#cur] == "[running...]" then
+            vim.api.nvim_buf_set_lines(buf, #cur - 1, #cur, false, {})
+          end
+        end
+        append_lines(buf, { "", "[exit code] " .. tostring(code) })
+      end
+      if options.track_scope then
+        state.last_scope_exit_code = code
+      end
     end,
   })
 end
@@ -405,7 +526,16 @@ function M.run_nearest()
     return
   end
 
-  run_command(command)
+  local parser = runner.output_parser
+  if type(parser) == "function" then
+    parser = parser()
+  end
+  run_command(command, {
+    track_scope = true,
+    runner = runner,
+    scope_kind = "nearest",
+    output_parser = parser or runner.parse_results,
+  })
 end
 
 function M.run_file()
@@ -428,7 +558,16 @@ function M.run_file()
     return
   end
 
-  run_command(command)
+  local parser = runner.output_parser
+  if type(parser) == "function" then
+    parser = parser()
+  end
+  run_command(command, {
+    track_scope = true,
+    runner = runner,
+    scope_kind = "file",
+    output_parser = parser or runner.parse_results,
+  })
 end
 
 function M.run_all()
@@ -451,7 +590,59 @@ function M.run_all()
     return
   end
 
-  run_command(command)
+  local parser = runner.output_parser
+  if type(parser) == "function" then
+    parser = parser()
+  end
+  run_command(command, {
+    track_scope = true,
+    runner = runner,
+    scope_kind = "all",
+    output_parser = parser or runner.parse_results,
+  })
+end
+
+local function build_failed_only_command()
+  if not (state.last_scope_command and type(state.last_scope_command.cmd) == "table") then
+    return nil, "[test-samurai] No previous scoped test command"
+  end
+
+  local failures = state.last_scope_failures or {}
+  if #failures == 0 then
+    return nil, nil
+  end
+
+  local runner = state.last_scope_runner
+  if not runner or type(runner.build_failed_command) ~= "function" then
+    local name = runner and runner.name or "unknown"
+    return nil, "[test-samurai] Runner does not support failed-only: " .. name
+  end
+
+  local ok_build, command = pcall(runner.build_failed_command, state.last_scope_command, failures, state.last_scope_kind)
+  if not ok_build or not command or type(command.cmd) ~= "table" or #command.cmd == 0 then
+    return nil, "[test-samurai] Runner failed to build failed-only command"
+  end
+
+  return command, nil
+end
+
+function M.run_failed_only()
+  if not (state.last_scope_command and type(state.last_scope_command.cmd) == "table") then
+    vim.notify("[test-samurai] No previous scoped test command", vim.log.levels.WARN)
+    return
+  end
+
+  local command, err = build_failed_only_command()
+  if not command then
+    if not err then
+      M.run_last()
+      return
+    end
+    vim.notify(err, vim.log.levels.WARN)
+    return
+  end
+
+  run_command(command, { save_last = false })
 end
 
 function M.show_output()
diff --git a/lua/test-samurai/init.lua b/lua/test-samurai/init.lua
index 8342807..d5246da 100644
--- a/lua/test-samurai/init.lua
+++ b/lua/test-samurai/init.lua
@@ -24,6 +24,10 @@ function M.test_last()
   core.run_last()
 end
 
+function M.test_failed_only()
+  core.run_failed_only()
+end
+
 function M.show_output()
   core.show_output()
 end
diff --git a/lua/test-samurai/runners/go.lua b/lua/test-samurai/runners/go.lua
index 6a31517..0896616 100644
--- a/lua/test-samurai/runners/go.lua
+++ b/lua/test-samurai/runners/go.lua
@@ -106,6 +106,18 @@ local function build_pkg_arg(spec)
   return "./" .. rel
 end
 
+local function collect_unique(list)
+  local out = {}
+  local seen = {}
+  for _, item in ipairs(list) do
+    if item and item ~= "" and not seen[item] then
+      seen[item] = true
+      table.insert(out, item)
+    end
+  end
+  return out
+end
+
 function runner.is_test_file(bufnr)
   local path = util.get_buf_path(bufnr)
   if not path or path == "" then
@@ -170,7 +182,7 @@ end
 function runner.build_command(spec)
   local pattern = build_run_pattern(spec)
   local pkg = build_pkg_arg(spec)
-  local cmd = { "go", "test", "-v", pkg, "-run", pattern }
+  local cmd = { "go", "test", "-json", pkg, "-run", pattern }
   return {
     cmd = cmd,
     cwd = spec.cwd,
@@ -188,7 +200,7 @@ function runner.build_file_command(bufnr)
   end
   local spec = { file = path, cwd = root }
   local pkg = build_pkg_arg(spec)
-  local cmd = { "go", "test", "-v", pkg }
+  local cmd = { "go", "test", "-json", pkg }
   return {
     cmd = cmd,
     cwd = root,
@@ -204,11 +216,125 @@ function runner.build_all_command(bufnr)
   if not root or root == "" then
     root = vim.loop.cwd()
   end
-  local cmd = { "go", "test", "-v", "./..." }
+  local cmd = { "go", "test", "-json", "./..." }
   return {
     cmd = cmd,
     cwd = root,
   }
 end
 
+function runner.parse_results(output)
+  if not output or output == "" then
+    return { passes = {}, failures = {}, skips = {} }
+  end
+  local passes = {}
+  local failures = {}
+  local skips = {}
+  for line in output:gmatch("[^\n]+") do
+    local ok, data = pcall(vim.json.decode, line)
+    if ok and type(data) == "table" then
+      if data.Test and data.Test ~= "" then
+        if data.Action == "pass" then
+          table.insert(passes, data.Test)
+        elseif data.Action == "fail" then
+          table.insert(failures, data.Test)
+        elseif data.Action == "skip" then
+          table.insert(skips, data.Test)
+        end
+      end
+    end
+  end
+  return {
+    passes = collect_unique(passes),
+    failures = collect_unique(failures),
+    skips = collect_unique(skips),
+  }
+end
+
+function runner.output_parser()
+  local seen_pass = {}
+  local seen_fail = {}
+  local failures = {}
+  local passes = {}
+  local skips = {}
+
+  return {
+    on_line = function(line, _state)
+      local ok, data = pcall(vim.json.decode, line)
+      if not ok or type(data) ~= "table" then
+        return nil
+      end
+      local name = data.Test
+      if not name or name == "" then
+        return nil
+      end
+      if data.Action == "pass" and not seen_pass[name] then
+        seen_pass[name] = true
+        table.insert(passes, name)
+        return {
+          passes = { name },
+          failures = {},
+          skips = {},
+          failures_all = vim.deepcopy(failures),
+        }
+      elseif data.Action == "fail" and not seen_fail[name] then
+        seen_fail[name] = true
+        table.insert(failures, name)
+        return {
+          passes = {},
+          failures = { name },
+          skips = {},
+          failures_all = vim.deepcopy(failures),
+        }
+      elseif data.Action == "skip" and not seen_pass[name] then
+        seen_pass[name] = true
+        table.insert(skips, name)
+        return {
+          passes = {},
+          failures = {},
+          skips = { name },
+          failures_all = vim.deepcopy(failures),
+        }
+      end
+      return nil
+    end,
+    on_complete = function(_output, _state)
+      return nil
+    end,
+  }
+end
+
+function runner.build_failed_command(last_command, failures, _scope_kind)
+  if not last_command or type(last_command.cmd) ~= "table" then
+    return nil
+  end
+  local pattern_parts = {}
+  for _, name in ipairs(failures or {}) do
+    table.insert(pattern_parts, escape_go_regex(name))
+  end
+  if #pattern_parts == 0 then
+    return nil
+  end
+  local pattern = "^(" .. table.concat(pattern_parts, "|") .. ")$"
+
+  local cmd = {}
+  local skip_next = false
+  for _, arg in ipairs(last_command.cmd) do
+    if skip_next then
+      skip_next = false
+    elseif arg == "-run" then
+      skip_next = true
+    else
+      table.insert(cmd, arg)
+    end
+  end
+  table.insert(cmd, "-run")
+  table.insert(cmd, pattern)
+
+  return {
+    cmd = cmd,
+    cwd = last_command.cwd,
+  }
+end
+
 return runner
diff --git a/lua/test-samurai/runners/js-jest.lua b/lua/test-samurai/runners/js-jest.lua
index 4aa0cba..6959ba2 100644
--- a/lua/test-samurai/runners/js-jest.lua
+++ b/lua/test-samurai/runners/js-jest.lua
@@ -4,4 +4,5 @@ return js.new({
   name = "js-jest",
   framework = "jest",
   command = { "npx", "jest" },
+  json_args = { "--json" },
 })
diff --git a/lua/test-samurai/runners/js-mocha.lua b/lua/test-samurai/runners/js-mocha.lua
index 8664f3e..d9813bf 100644
--- a/lua/test-samurai/runners/js-mocha.lua
+++ b/lua/test-samurai/runners/js-mocha.lua
@@ -5,4 +5,5 @@ return js.new({
   framework = "mocha",
   command = { "npx", "mocha" },
   all_glob = "test/**/*.test.js",
+  json_args = { "--reporter", "json-stream" },
 })
diff --git a/lua/test-samurai/runners/js-vitest.lua b/lua/test-samurai/runners/js-vitest.lua
index d56b206..4d17b7f 100644
--- a/lua/test-samurai/runners/js-vitest.lua
+++ b/lua/test-samurai/runners/js-vitest.lua
@@ -4,4 +4,5 @@ return js.new({
   name = "js-vitest",
   framework = "vitest",
   command = { "npx", "vitest" },
+  json_args = { "--reporter", "tap-flat" },
 })
diff --git a/lua/test-samurai/runners/js.lua b/lua/test-samurai/runners/js.lua
index f471e78..e864da3 100644
--- a/lua/test-samurai/runners/js.lua
+++ b/lua/test-samurai/runners/js.lua
@@ -28,6 +28,48 @@ local function is_js_test_file(bufnr, filetypes, patterns)
   return false
 end
 
+local function append_args(cmd, args)
+  if not args or #args == 0 then
+    return
+  end
+  for _, arg in ipairs(args) do
+    table.insert(cmd, arg)
+  end
+end
+
+local function escape_regex(s)
+  s = s or ""
+  return (s:gsub("([\\.^$|()%%[%]{}*+?%-])", "\\\\%1"))
+end
+
+local function build_pattern(names)
+  local parts = {}
+  for _, name in ipairs(names or {}) do
+    if name and name ~= "" then
+      table.insert(parts, escape_regex(name))
+    end
+  end
+  if #parts == 0 then
+    return nil
+  end
+  return table.concat(parts, "|")
+end
+
+local function find_test_file_arg(cmd)
+  if not cmd then
+    return nil
+  end
+  for i = #cmd, 1, -1 do
+    local arg = cmd[i]
+    if type(arg) == "string" and arg:sub(1, 1) ~= "-" then
+      if arg:match("%.test%.[jt]sx?$") or arg:match("%.spec%.[jt]sx?$") then
+        return arg
+      end
+    end
+  end
+  return nil
+end
+
 local function find_block_end(lines, start_idx)
   local depth = 0
   local started = false
@@ -221,6 +263,8 @@ function M.new(opts)
   runner.framework = cfg.framework or "jest"
   runner.command = cfg.command or { "npx", runner.framework }
   runner.all_glob = cfg.all_glob
+  runner.json_args = cfg.json_args or {}
+  runner.failed_only_flag = cfg.failed_only_flag
 
   runner.filetypes = {}
   if cfg.filetypes then
@@ -271,6 +315,7 @@ function M.new(opts)
 
   local function build_jest(spec)
     local cmd = vim.deepcopy(runner.command)
+    append_args(cmd, runner.json_args)
     table.insert(cmd, spec.file)
     table.insert(cmd, "-t")
     table.insert(cmd, spec.test_name)
@@ -279,6 +324,7 @@ function M.new(opts)
 
   local function build_mocha(spec)
     local cmd = vim.deepcopy(runner.command)
+    append_args(cmd, runner.json_args)
     local target = spec.full_name or spec.test_name
     table.insert(cmd, "--fgrep")
     table.insert(cmd, target)
@@ -288,6 +334,7 @@ function M.new(opts)
 
   local function build_vitest(spec)
     local cmd = vim.deepcopy(runner.command)
+    append_args(cmd, runner.json_args)
     table.insert(cmd, spec.file)
     table.insert(cmd, "-t")
     table.insert(cmd, spec.test_name)
@@ -332,6 +379,7 @@ function M.new(opts)
       })
     end
     local cmd = vim.deepcopy(runner.command)
+    append_args(cmd, runner.json_args)
     table.insert(cmd, path)
     return {
       cmd = cmd,
@@ -360,6 +408,7 @@ function M.new(opts)
       root = vim.loop.cwd()
     end
     local cmd = vim.deepcopy(runner.command)
+    append_args(cmd, runner.json_args)
     if runner.framework == "mocha" and runner.all_glob then
       table.insert(cmd, runner.all_glob)
     end
@@ -369,6 +418,226 @@ function M.new(opts)
     }
   end
 
+  local function parse_jest_like(output)
+    local ok, data = pcall(vim.json.decode, output)
+    if not ok or type(data) ~= "table" then
+      return nil
+    end
+    local passes = {}
+    local failures = {}
+    local skips = {}
+    for _, result in ipairs(data.testResults or {}) do
+      for _, assertion in ipairs(result.assertionResults or {}) do
+        local title = assertion.fullName or assertion.title
+        if assertion.status == "passed" and title then
+          table.insert(passes, title)
+        elseif assertion.status == "failed" and title then
+          table.insert(failures, title)
+        elseif (assertion.status == "pending" or assertion.status == "skipped" or assertion.status == "todo")
+          and title then
+          table.insert(skips, title)
+        end
+      end
+    end
+    return { passes = passes, failures = failures, skips = skips }
+  end
+
+  local function parse_mocha(output)
+    local ok, data = pcall(vim.json.decode, output)
+    if not ok or type(data) ~= "table" then
+      return nil
+    end
+    local passes = {}
+    local failures = {}
+    local skips = {}
+    if type(data.tests) == "table" then
+      for _, test in ipairs(data.tests) do
+        local title = test.fullTitle or test.title
+        if test.state == "passed" and title then
+          table.insert(passes, title)
+        elseif test.state == "failed" and title then
+          table.insert(failures, title)
+        elseif test.state == "pending" and title then
+          table.insert(skips, title)
+        end
+      end
+    elseif type(data.passes) == "table" or type(data.failures) == "table" then
+      for _, test in ipairs(data.passes or {}) do
+        local title = test.fullTitle or test.title
+        if title then
+          table.insert(passes, title)
+        end
+      end
+      for _, test in ipairs(data.failures or {}) do
+        local title = test.fullTitle or test.title
+        if title then
+          table.insert(failures, title)
+        end
+      end
+      for _, test in ipairs(data.pending or {}) do
+        local title = test.fullTitle or test.title
+        if title then
+          table.insert(skips, title)
+        end
+      end
+    end
+    return { passes = passes, failures = failures, skips = skips }
+  end
+
+  local function parse_output(output)
+    if runner.framework == "mocha" then
+      return parse_mocha(output)
+    end
+    return parse_jest_like(output)
+  end
+
+  function runner.parse_results(output)
+    return parse_output(output)
+  end
+
+  function runner.output_parser()
+    local state = { raw = {}, done = false }
+    local failures = {}
+    local skips = {}
+    return {
+      on_line = function(line, _state)
+        if state.done then
+          return nil
+        end
+        if runner.framework == "mocha" and runner.json_args then
+          local uses_stream = false
+          for i = 1, #runner.json_args - 1 do
+            if runner.json_args[i] == "--reporter" and runner.json_args[i + 1] == "json-stream" then
+              uses_stream = true
+              break
+            end
+          end
+          if uses_stream then
+            local ok, data = pcall(vim.json.decode, line)
+            if ok and type(data) == "table" and data.event then
+              if data.event == "pass" and data.fullTitle then
+                return {
+                  passes = { data.fullTitle },
+                  failures = {},
+                  skips = {},
+                  failures_all = vim.deepcopy(failures),
+                }
+              elseif data.event == "fail" and data.fullTitle then
+                table.insert(failures, data.fullTitle)
+                return {
+                  passes = {},
+                  failures = { data.fullTitle },
+                  skips = {},
+                  failures_all = vim.deepcopy(failures),
+                }
+              elseif data.event == "pending" and data.fullTitle then
+                table.insert(skips, data.fullTitle)
+                return {
+                  passes = {},
+                  failures = {},
+                  skips = { data.fullTitle },
+                  failures_all = vim.deepcopy(failures),
+                }
+              end
+            end
+            return nil
+          end
+        end
+        if runner.framework == "vitest" and runner.json_args then
+          local uses_tap = false
+          for i = 1, #runner.json_args - 1 do
+            if runner.json_args[i] == "--reporter" and (runner.json_args[i + 1] == "tap" or runner.json_args[i + 1] == "tap-flat") then
+              uses_tap = true
+              break
+            end
+          end
+          if uses_tap then
+            local ok_title = line:match("^ok%s+%d+%s+%-%s+(.+)")
+            if ok_title then
+              local skip_title = ok_title:match("^(.-)%s+#%s+SKIP.*$")
+              if skip_title then
+                skip_title = skip_title:gsub("%s+$", "")
+                table.insert(skips, skip_title)
+                return {
+                  passes = {},
+                  failures = {},
+                  skips = { skip_title },
+                  failures_all = vim.deepcopy(failures),
+                }
+              end
+              ok_title = ok_title:gsub("%s+#%s+time=.*$", "")
+              return {
+                passes = { ok_title },
+                failures = {},
+                skips = {},
+                failures_all = vim.deepcopy(failures),
+              }
+            end
+            local fail_title = line:match("^not ok%s+%d+%s+%-%s+(.+)")
+            if fail_title then
+              fail_title = fail_title:gsub("%s+#%s+time=.*$", "")
+              table.insert(failures, fail_title)
+              return {
+                passes = {},
+                failures = { fail_title },
+                skips = {},
+                failures_all = vim.deepcopy(failures),
+              }
+            end
+            return nil
+          end
+        end
+        table.insert(state.raw, line)
+        local output = table.concat(state.raw, "\n")
+        local results = parse_output(output)
+        if results then
+          state.done = true
+        end
+        return results
+      end,
+      on_complete = function(output, _state)
+        if state.done then
+          return nil
+        end
+        local results = parse_output(output)
+        if results then
+          state.done = true
+        end
+        return results
+      end,
+    }
+  end
+
+  function runner.build_failed_command(last_command, failures, scope_kind)
+    local pattern = build_pattern(failures)
+    if not pattern then
+      return nil
+    end
+
+    local cmd = vim.deepcopy(runner.command)
+    append_args(cmd, runner.json_args)
+
+    if runner.framework == "mocha" then
+      table.insert(cmd, "--grep")
+      table.insert(cmd, pattern)
+    else
+      table.insert(cmd, "-t")
+      table.insert(cmd, pattern)
+    end
+
+    if scope_kind ~= "all" and last_command then
+      local file = find_test_file_arg(last_command.cmd)
+      if file then
+        table.insert(cmd, file)
+      end
+    end
+
+    return {
+      cmd = cmd,
+      cwd = last_command and last_command.cwd or nil,
+    }
+  end
+
   return runner
 end
 
diff --git a/lua/test-samurai/runners/lua-plenary.lua b/lua/test-samurai/runners/lua-plenary.lua
deleted file mode 100644
index d3eeecb..0000000
--- a/lua/test-samurai/runners/lua-plenary.lua
+++ /dev/null
@@ -1,240 +0,0 @@
-local util = require("test-samurai.util")
-
-local runner = {
-  name = "lua-plenary",
-  framework = "plenary",
-}
-
-local function is_lua_test_path(path)
-  if not path or path == "" then
-    return false
-  end
-  if not path:match("%.lua$") then
-    return false
-  end
-  if path:match("_spec%.lua$") then
-    return true
-  end
-  if path:match("/tests/") then
-    return true
-  end
-  return false
-end
-
-function runner.is_test_file(bufnr)
-  local path = util.get_buf_path(bufnr)
-  return is_lua_test_path(path)
-end
-
-local function find_repo_root(file)
-  local root = util.find_root(file, { ".git", "tests", "lua", "plugin" })
-  if not root or root == "" then
-    root = vim.loop.cwd()
-  end
-  return root
-end
-
-local function minimal_init_for(root)
-  return vim.fs.joinpath(root, "tests", "minimal_init.lua")
-end
-
-local function escape_for_ex_double_quotes(s)
-  s = s or ""
-  s = s:gsub("\\", "\\\\")
-  s = s:gsub('"', '\\"')
-  return s
-end
-
-local function count_keyword(line, kw)
-  local c = 0
-  local pat = "%f[%w]" .. kw .. "%f[%W]"
-  for _ in line:gmatch(pat) do
-    c = c + 1
-  end
-  return c
-end
-
-local function find_end_lua_block(lines, start_idx)
-  local depth = 0
-  local started = false
-  for i = start_idx, #lines do
-    local line = lines[i]
-    local fnc = count_keyword(line, "function")
-    local endc = count_keyword(line, "end")
-    if fnc > 0 then
-      depth = depth + fnc
-      started = true
-    end
-    if started and endc > 0 then
-      depth = depth - endc
-      if depth <= 0 then
-        return i - 1
-      end
-    end
-  end
-  return #lines - 1
-end
-
-local function collect_lua_structs(lines)
-  local describes = {}
-  local tests = {}
-
-  for i, line in ipairs(lines) do
-    local dname = line:match("^%s*describe%s*%(%s*['\"`]([^'\"`]+)['\"`]")
-    if dname then
-      local start0 = i - 1
-      local end0 = find_end_lua_block(lines, i)
-      table.insert(describes, { kind = "describe", name = dname, start = start0, ["end"] = end0 })
-    else
-      local tname = line:match("^%s*it%s*%(%s*['\"`]([^'\"`]+)['\"`]")
-      if tname then
-        local start0 = i - 1
-        local end0 = find_end_lua_block(lines, i)
-        table.insert(tests, { kind = "it", name = tname, start = start0, ["end"] = end0 })
-      end
-    end
-  end
-
-  return describes, tests
-end
-
-local function build_full_name(lines, idx, leaf_name)
-  local parts = { leaf_name }
-  for i = idx - 1, 1, -1 do
-    local line = lines[i]
-    local dname = line:match("^%s*describe%s*%(%s*['\"`]([^'\"`]+)['\"`]")
-    if dname then
-      table.insert(parts, 1, dname)
-    end
-  end
-  return table.concat(parts, " ")
-end
-
-function runner.find_nearest(bufnr, row, _col)
-  if not runner.is_test_file(bufnr) then
-    return nil, "not a lua test file"
-  end
-
-  local lines = util.get_buf_lines(bufnr)
-  local describes, tests = collect_lua_structs(lines)
-
-  for _, t in ipairs(tests) do
-    if row >= t.start and row <= t["end"] then
-      local full = build_full_name(lines, t.start + 1, t.name)
-      local file = util.get_buf_path(bufnr)
-      local root = find_repo_root(file)
-      return { file = file, cwd = root, test_name = t.name, full_name = full, kind = "it" }
-    end
-  end
-
-  local best_describe = nil
-  for _, d in ipairs(describes) do
-    if row >= d.start and row <= d["end"] then
-      if not best_describe or d.start >= best_describe.start then
-        best_describe = d
-      end
-    end
-  end
-  if best_describe then
-    local full = build_full_name(lines, best_describe.start + 1, best_describe.name)
-    local file = util.get_buf_path(bufnr)
-    local root = find_repo_root(file)
-    return { file = file, cwd = root, test_name = best_describe.name, full_name = full, kind = "describe" }
-  end
-
-  local start = row + 1
-  if start > #lines then
-    start = #lines
-  elseif start < 1 then
-    start = 1
-  end
-  for i = start, 1, -1 do
-    local line = lines[i]
-    local tname = line:match("^%s*it%s*%(%s*['\"`]([^'\"`]+)['\"`]")
-    if tname then
-      local full = build_full_name(lines, i, tname)
-      local file = util.get_buf_path(bufnr)
-      local root = find_repo_root(file)
-      return { file = file, cwd = root, test_name = tname, full_name = full, kind = "it" }
-    end
-    local dname = line:match("^%s*describe%s*%(%s*['\"`]([^'\"`]+)['\"`]")
-    if dname then
-      local full = build_full_name(lines, i, dname)
-      local file = util.get_buf_path(bufnr)
-      local root = find_repo_root(file)
-      return { file = file, cwd = root, test_name = dname, full_name = full, kind = "describe" }
-    end
-  end
-
-  return nil, "no test call found"
-end
-
-local function ex_plenary_busted_file(file, filter_name)
-  local ex = "PlenaryBustedFile " .. vim.fn.fnameescape(file)
-  if filter_name and filter_name ~= "" then
-    local f = escape_for_ex_double_quotes(filter_name)
-    ex = ex .. ' { busted_args = { "--filter", "' .. f .. '" } }'
-  end
-  return ex
-end
-
-function runner.build_command(spec)
-  local root = spec and spec.cwd or vim.loop.cwd()
-  local minit = minimal_init_for(root)
-
-  local cmd = {
-    "nvim",
-    "--headless",
-    "-u",
-    minit,
-    "-c",
-    ex_plenary_busted_file(spec.file, spec.test_name),
-    "-c",
-    "qa",
-  }
-
-  return { cmd = cmd, cwd = root }
-end
-
-function runner.build_file_command(bufnr)
-  local file = util.get_buf_path(bufnr)
-  if not file or file == "" then
-    return nil
-  end
-  local root = find_repo_root(file)
-  local minit = minimal_init_for(root)
-
-  local cmd = {
-    "nvim",
-    "--headless",
-    "-u",
-    minit,
-    "-c",
-    ex_plenary_busted_file(file, nil),
-    "-c",
-    "qa",
-  }
-
-  return { cmd = cmd, cwd = root }
-end
-
-function runner.build_all_command(bufnr)
-  local file = util.get_buf_path(bufnr)
-  local root = find_repo_root(file)
-  local minit = minimal_init_for(root)
-
-  local cmd = {
-    "nvim",
-    "--headless",
-    "-u",
-    minit,
-    "-c",
-    "PlenaryBustedDirectory tests",
-    "-c",
-    "qa",
-  }
-
-  return { cmd = cmd, cwd = root }
-end
-
-return runner
diff --git a/plugin/test-samurai.lua b/plugin/test-samurai.lua
index a7e634f..98b8e15 100644
--- a/plugin/test-samurai.lua
+++ b/plugin/test-samurai.lua
@@ -23,6 +23,10 @@ vim.api.nvim_create_user_command("TSamLast", function()
   require("test-samurai").test_last()
 end, { desc = "test-samurai: rerun last test command" })
 
+vim.api.nvim_create_user_command("TSamFailedOnly", function()
+  require("test-samurai").test_failed_only()
+end, { desc = "test-samurai: rerun failed tests from last scoped run" })
+
 vim.keymap.set("n", "<leader>tn", function()
   require("test-samurai").test_nearest()
 end, { desc = "test-samurai: run nearest test" })
@@ -42,3 +46,7 @@ end, { desc = "test-samurai: run all tests in project (per runner)" })
 vim.keymap.set("n", "<leader>tl", function()
   require("test-samurai").test_last()
 end, { desc = "test-samurai: rerun last test command" })
+
+vim.keymap.set("n", "<leader>te", function()
+  require("test-samurai").test_failed_only()
+end, { desc = "test-samurai: rerun failed tests from last scoped run" })
diff --git a/tests/test_samurai_commands_spec.lua b/tests/test_samurai_commands_spec.lua
new file mode 100644
index 0000000..fb39566
--- /dev/null
+++ b/tests/test_samurai_commands_spec.lua
@@ -0,0 +1,15 @@
+describe("test-samurai commands", function()
+  before_each(function()
+    vim.g.loaded_test_samurai_plugin = nil
+    vim.cmd("runtime plugin/test-samurai.lua")
+  end)
+
+  it("registers TSamFailedOnly command", function()
+    assert.equals(2, vim.fn.exists(":TSamFailedOnly"))
+  end)
+
+  it("registers <leader>te keymap", function()
+    local map = vim.fn.maparg("<leader>te", "n")
+    assert.is_true(map ~= nil and map ~= "")
+  end)
+end)
diff --git a/tests/test_samurai_failed_only_spec.lua b/tests/test_samurai_failed_only_spec.lua
new file mode 100644
index 0000000..9d3fdf1
--- /dev/null
+++ b/tests/test_samurai_failed_only_spec.lua
@@ -0,0 +1,225 @@
+local test_samurai = require("test-samurai")
+local core = require("test-samurai.core")
+
+local function mkbuf(path, ft, lines)
+  local bufnr = vim.api.nvim_create_buf(false, true)
+  vim.api.nvim_buf_set_name(bufnr, path)
+  vim.bo[bufnr].filetype = ft
+  if lines then
+    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
+  end
+  return bufnr
+end
+
+local function stub_jobstart(opts_config)
+  local calls = {}
+  local orig = vim.fn.jobstart
+  local idx = 0
+  local config = opts_config or {}
+  vim.fn.jobstart = function(cmd, opts)
+    idx = idx + 1
+    table.insert(calls, { cmd = cmd, opts = opts })
+    local code = 0
+    if type(config.exit_codes) == "table" then
+      code = config.exit_codes[idx] or 0
+    elseif type(config.exit_codes) == "number" then
+      code = config.exit_codes
+    end
+    local out = config.stdout and config.stdout[idx] or nil
+    if out and opts and opts.on_stdout then
+      if type(out) == "string" then
+        out = { out }
+      end
+      opts.on_stdout(1, out, nil)
+    end
+    local err = config.stderr and config.stderr[idx] or nil
+    if err and opts and opts.on_stderr then
+      if type(err) == "string" then
+        err = { err }
+      end
+      opts.on_stderr(1, err, nil)
+    end
+    if opts and opts.on_exit then
+      opts.on_exit(1, code, nil)
+    end
+    return 1
+  end
+  return calls, orig
+end
+
+describe("TSamFailedOnly", function()
+  before_each(function()
+    test_samurai.setup()
+  end)
+
+  it("reruns failed jest tests with --onlyFailures", function()
+    local json = vim.json.encode({
+      testResults = {
+        {
+          assertionResults = {
+            { status = "passed", title = "inner 1", fullName = "outer inner 1" },
+            { status = "failed", title = "inner 2", fullName = "outer inner 2" },
+          },
+        },
+      },
+    })
+
+    local calls, orig_jobstart = stub_jobstart({
+      exit_codes = { 1, 0 },
+      stdout = { { json } },
+    })
+
+    local bufnr = mkbuf("/tmp/project/foo_failed_only.test.ts", "typescript", {
+      'describe("outer", function() {',
+      '  it("inner 1", function() {',
+      "    -- inside 1",
+      "  })",
+      "",
+      '  it("inner 2", function() {',
+      "    -- inside 2",
+      "  })",
+      "})",
+    })
+
+    vim.api.nvim_set_current_buf(bufnr)
+    vim.api.nvim_win_set_cursor(0, { 7, 0 })
+
+    core.run_nearest()
+    core.run_failed_only()
+
+    vim.fn.jobstart = orig_jobstart
+
+    assert.equals(2, #calls)
+    assert.are.same(
+      { "npx", "jest", "--json", "/tmp/project/foo_failed_only.test.ts", "-t", "inner 2" },
+      calls[1].cmd
+    )
+    assert.are.same(
+      { "npx", "jest", "--json", "-t", "outer inner 2", "/tmp/project/foo_failed_only.test.ts" },
+      calls[2].cmd
+    )
+  end)
+
+  it("falls back to TSamLast when last run had no failures", function()
+    local json = vim.json.encode({
+      testResults = {
+        {
+          assertionResults = {
+            { status = "passed", title = "inner 1", fullName = "outer inner 1" },
+          },
+        },
+      },
+    })
+
+    local calls, orig_jobstart = stub_jobstart({
+      exit_codes = { 0, 0 },
+      stdout = { { json } },
+    })
+
+    local bufnr = mkbuf("/tmp/project/foo_failed_only_pass.test.ts", "typescript", {
+      'describe("outer", function() {',
+      '  it("inner 1", function() {',
+      "    -- inside 1",
+      "  })",
+      "",
+      '  it("inner 2", function() {',
+      "    -- inside 2",
+      "  })",
+      "})",
+    })
+
+    vim.api.nvim_set_current_buf(bufnr)
+    vim.api.nvim_win_set_cursor(0, { 7, 0 })
+
+    core.run_nearest()
+    core.run_failed_only()
+
+    vim.fn.jobstart = orig_jobstart
+
+    assert.equals(2, #calls)
+    assert.are.same(calls[1].cmd, calls[2].cmd)
+  end)
+
+  it("reruns failed go tests with -run regex", function()
+    local json_lines = {
+      vim.json.encode({ Action = "fail", Test = "TestFoo/first" }),
+      vim.json.encode({ Action = "fail", Test = "TestBar" }),
+    }
+
+    local calls, orig_jobstart = stub_jobstart({
+      exit_codes = { 1, 0 },
+      stdout = { json_lines },
+    })
+
+    local bufnr = mkbuf("/tmp/project/foo_failed_only_test.go", "go", {
+      "package main",
+      "import \"testing\"",
+      "",
+      "func TestFoo(t *testing.T) {",
+      "  t.Run(\"first\", func(t *testing.T) {",
+      "    -- inside first",
+      "  })",
+      "}",
+      "",
+      "func TestBar(t *testing.T) {",
+      "  -- inside bar",
+      "}",
+    })
+
+    vim.api.nvim_set_current_buf(bufnr)
+
+    core.run_all()
+    core.run_failed_only()
+
+    vim.fn.jobstart = orig_jobstart
+
+    assert.equals(2, #calls)
+    assert.are.same({ "go", "test", "-json", "./..." }, calls[1].cmd)
+    assert.are.same({ "go", "test", "-json", "./...", "-run", "^(TestFoo/first|TestBar)$" }, calls[2].cmd)
+  end)
+
+  it("does not affect TSamLast history", function()
+    local json = vim.json.encode({
+      testResults = {
+        {
+          assertionResults = {
+            { status = "failed", title = "inner 2", fullName = "outer inner 2" },
+          },
+        },
+      },
+    })
+
+    local calls, orig_jobstart = stub_jobstart({
+      exit_codes = { 1, 1, 1 },
+      stdout = { { json } },
+    })
+
+    local bufnr = mkbuf("/tmp/project/foo_failed_only_last.test.ts", "typescript", {
+      'describe("outer", function() {',
+      '  it("inner 1", function() {',
+      "    -- inside 1",
+      "  })",
+      "",
+      '  it("inner 2", function() {',
+      "    -- inside 2",
+      "  })",
+      "})",
+    })
+
+    vim.api.nvim_set_current_buf(bufnr)
+    vim.api.nvim_win_set_cursor(0, { 7, 0 })
+
+    core.run_nearest()
+    core.run_failed_only()
+    core.run_last()
+
+    vim.fn.jobstart = orig_jobstart
+
+    assert.equals(3, #calls)
+    assert.are.same(calls[1].cmd, calls[3].cmd)
+    assert.are.same(
+      { "npx", "jest", "--json", "-t", "outer inner 2", "/tmp/project/foo_failed_only_last.test.ts" },
+      calls[2].cmd
+    )
+  end)
+end)
diff --git a/tests/test_samurai_go_spec.lua b/tests/test_samurai_go_spec.lua
index ef3629c..8e1048a 100644
--- a/tests/test_samurai_go_spec.lua
+++ b/tests/test_samurai_go_spec.lua
@@ -95,7 +95,7 @@ describe("test-samurai go runner", function()
 
     local cmd_spec_sub = go_runner.build_command(spec_sub)
     assert.are.same(
-      { "go", "test", "-v", "./pkg", "-run", "^TestFoo/first$" },
+      { "go", "test", "-json", "./pkg", "-run", "^TestFoo/first$" },
       cmd_spec_sub.cmd
     )
 
@@ -108,7 +108,7 @@ describe("test-samurai go runner", function()
 
     local cmd_spec_func = go_runner.build_command(spec_func)
     assert.are.same(
-      { "go", "test", "-v", "./", "-run", "^TestFoo($|/)" },
+      { "go", "test", "-json", "./", "-run", "^TestFoo($|/)" },
       cmd_spec_func.cmd
     )
   end)
diff --git a/tests/test_samurai_js_spec.lua b/tests/test_samurai_js_spec.lua
index a4c4f84..14b5d4c 100644
--- a/tests/test_samurai_js_spec.lua
+++ b/tests/test_samurai_js_spec.lua
@@ -1,5 +1,6 @@
 local jest = require("test-samurai.runners.js-jest")
 local mocha = require("test-samurai.runners.js-mocha")
+local vitest = require("test-samurai.runners.js-vitest")
 local util = require("test-samurai.util")
 
 describe("test-samurai js runner (jest)", function()
@@ -51,7 +52,7 @@ describe("test-samurai js runner (jest)", function()
     assert.is_true(spec.cwd:match("tmp$") ~= nil)
 
     local cmd_spec = jest.build_command(spec)
-    assert.are.same({ "npx", "jest", spec.file, "-t", "inner 2" }, cmd_spec.cmd)
+    assert.are.same({ "npx", "jest", "--json", spec.file, "-t", "inner 2" }, cmd_spec.cmd)
   end)
 
   it("returns describe block when cursor is between it() calls", function()
@@ -133,7 +134,7 @@ describe("test-samurai js runner (mocha)", function()
     local cmd_spec = mocha.build_command(spec)
 
     assert.are.same(
-      { "npx", "mocha", "--fgrep", "outer inner 2", spec.file },
+      { "npx", "mocha", "--reporter", "json-stream", "--fgrep", "outer inner 2", spec.file },
       cmd_spec.cmd
     )
     assert.equals("/tmp/project", cmd_spec.cwd)
@@ -154,7 +155,47 @@ describe("test-samurai js runner (mocha)", function()
     util.find_root = orig_find_root
 
     assert.are.same(
-      { "npx", "mocha", "test/**/*.test.js" },
+      { "npx", "mocha", "--reporter", "json-stream", "test/**/*.test.js" },
+      cmd_spec.cmd
+    )
+    assert.equals("/tmp/project", cmd_spec.cwd)
+  end)
+end)
+
+describe("test-samurai js runner (vitest)", function()
+  it("builds vitest command with tap-flat reporter", function()
+    local spec = {
+      file = "/tmp/project/test/foo_nearest.test.ts",
+      cwd = "/tmp/project",
+      test_name = "inner 2",
+      full_name = "outer inner 2",
+    }
+
+    local cmd_spec = vitest.build_command(spec)
+
+    assert.are.same(
+      { "npx", "vitest", "--reporter", "tap-flat", spec.file, "-t", "inner 2" },
+      cmd_spec.cmd
+    )
+    assert.equals("/tmp/project", cmd_spec.cwd)
+  end)
+
+  it("builds vitest all command with tap-flat reporter", function()
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_buf_set_name(bufnr, "/tmp/project/test/foo_all.test.ts")
+    vim.bo[bufnr].filetype = "typescript"
+
+    local orig_find_root = util.find_root
+    util.find_root = function(path, markers)
+      return "/tmp/project"
+    end
+
+    local cmd_spec = vitest.build_all_command(bufnr)
+
+    util.find_root = orig_find_root
+
+    assert.are.same(
+      { "npx", "vitest", "--reporter", "tap-flat" },
       cmd_spec.cmd
     )
     assert.equals("/tmp/project", cmd_spec.cwd)
diff --git a/tests/test_samurai_last_spec.lua b/tests/test_samurai_last_spec.lua
index 3f5a7f4..334a0d9 100644
--- a/tests/test_samurai_last_spec.lua
+++ b/tests/test_samurai_last_spec.lua
@@ -49,7 +49,7 @@ describe("TSamLast", function()
     vim.fn.jobstart = orig_jobstart
 
     assert.equals(2, #calls)
-    assert.are.same({ "go", "test", "-v", "./", "-run", "^TestFoo/first$" }, calls[1].cmd)
+    assert.are.same({ "go", "test", "-json", "./", "-run", "^TestFoo/first$" }, calls[1].cmd)
     assert.are.same(calls[1].cmd, calls[2].cmd)
     assert.equals(calls[1].opts.cwd, calls[2].opts.cwd)
   end)
@@ -79,48 +79,10 @@ describe("TSamLast", function()
 
     assert.equals(2, #calls)
     assert.are.same(
-      { "npx", "jest", "/tmp/project/foo_last.test.ts", "-t", "inner 2" },
+      { "npx", "jest", "--json", "/tmp/project/foo_last.test.ts", "-t", "inner 2" },
       calls[1].cmd
     )
     assert.are.same(calls[1].cmd, calls[2].cmd)
     assert.equals(calls[1].opts.cwd, calls[2].opts.cwd)
   end)
-
-  it("reruns last Lua command", function()
-    local calls, orig_jobstart = capture_jobstart()
-
-    local bufnr = mkbuf("/tmp/project/foo_last_spec.lua", "lua", {
-      "describe('outer', function()",
-      "  it('inner 1', function()",
-      "    local x = 1",
-      "  end)",
-      "",
-      "  it('inner 2', function()",
-      "    local y = 2",
-      "  end)",
-      "end)",
-    })
-
-    vim.api.nvim_set_current_buf(bufnr)
-    vim.api.nvim_win_set_cursor(0, { 7, 0 })
-
-    core.run_nearest()
-    core.run_last()
-
-    vim.fn.jobstart = orig_jobstart
-
-    assert.equals(2, #calls)
-    assert.are.same({
-      "nvim",
-      "--headless",
-      "-u",
-      "/tmp/project/tests/minimal_init.lua",
-      "-c",
-      'PlenaryBustedFile /tmp/project/foo_last_spec.lua { busted_args = { "--filter", "inner 2" } }',
-      "-c",
-      "qa",
-    }, calls[1].cmd)
-    assert.are.same(calls[1].cmd, calls[2].cmd)
-    assert.equals(calls[1].opts.cwd, calls[2].opts.cwd)
-  end)
 end)
diff --git a/tests/test_samurai_lua_spec.lua b/tests/test_samurai_lua_spec.lua
deleted file mode 100644
index 25286d2..0000000
--- a/tests/test_samurai_lua_spec.lua
+++ /dev/null
@@ -1,130 +0,0 @@
-local test_samurai = require("test-samurai")
-local lua_runner = require("test-samurai.runners.lua-plenary")
-local util = require("test-samurai.util")
-
-local function mkbuf(path, ft, lines)
-  local bufnr = vim.api.nvim_create_buf(false, true)
-  vim.api.nvim_buf_set_name(bufnr, path)
-  vim.bo[bufnr].filetype = ft
-  if lines then
-    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
-  end
-  return bufnr
-end
-
-describe("test-samurai lua runner (plenary)", function()
-  it("detects lua spec files by suffix", function()
-    local bufnr = mkbuf("/tmp/test_samurai_lua_spec_unique_1_spec.lua", "lua")
-    assert.is_true(lua_runner.is_test_file(bufnr))
-  end)
-
-  it("finds nearest it() when cursor is inside it block and builds filtered command", function()
-    local bufnr = mkbuf("/tmp/project/tests/test_samurai_lua_nearest_unique_2_spec.lua", "lua", {
-      "describe('outer', function()",
-      "  it('inner 1', function()",
-      "    local x = 1",
-      "  end)",
-      "",
-      "  it('inner 2', function()",
-      "    local y = 2",
-      "  end)",
-      "end)",
-    })
-
-    local orig_find_root = util.find_root
-    util.find_root = function()
-      return "/tmp/project"
-    end
-
-    local spec, err = lua_runner.find_nearest(bufnr, 6, 0)
-
-    util.find_root = orig_find_root
-
-    assert.is_nil(err)
-    assert.is_not_nil(spec)
-    assert.equals("inner 2", spec.test_name)
-    assert.equals("outer inner 2", spec.full_name)
-    assert.equals("/tmp/project", spec.cwd)
-
-    local cmd_spec = lua_runner.build_command(spec)
-    assert.equals("/tmp/project", cmd_spec.cwd)
-    assert.are.same({
-      "nvim",
-      "--headless",
-      "-u",
-      "/tmp/project/tests/minimal_init.lua",
-      "-c",
-      'PlenaryBustedFile ' .. spec.file .. ' { busted_args = { "--filter", "inner 2" } }',
-      "-c",
-      "qa",
-    }, cmd_spec.cmd)
-  end)
-
-  it("returns describe block when cursor is between it() calls", function()
-    local bufnr = mkbuf("/tmp/project/tests/test_samurai_lua_between_unique_3_spec.lua", "lua", {
-      "describe('outer', function()",
-      "  it('inner 1', function()",
-      "    local x = 1",
-      "  end)",
-      "",
-      "  it('inner 2', function()",
-      "    local y = 2",
-      "  end)",
-      "end)",
-    })
-
-    local orig_find_root = util.find_root
-    util.find_root = function()
-      return "/tmp/project"
-    end
-
-    local spec, err = lua_runner.find_nearest(bufnr, 4, 0)
-
-    util.find_root = orig_find_root
-
-    assert.is_nil(err)
-    assert.is_not_nil(spec)
-    assert.equals("outer", spec.test_name)
-    assert.equals("outer", spec.full_name)
-    assert.equals("describe", spec.kind)
-  end)
-
-  it("builds all command via PlenaryBustedDirectory", function()
-    local bufnr = mkbuf("/tmp/project/tests/test_samurai_core_spec_unique_4_spec.lua", "lua")
-
-    local orig_find_root = util.find_root
-    util.find_root = function()
-      return "/tmp/project"
-    end
-
-    local cmd_spec = lua_runner.build_all_command(bufnr)
-
-    util.find_root = orig_find_root
-
-    assert.are.same({
-      "nvim",
-      "--headless",
-      "-u",
-      "/tmp/project/tests/minimal_init.lua",
-      "-c",
-      "PlenaryBustedDirectory tests",
-      "-c",
-      "qa",
-    }, cmd_spec.cmd)
-    assert.equals("/tmp/project", cmd_spec.cwd)
-  end)
-
-  it("core selects lua runner for *_spec.lua buffers", function()
-    test_samurai.setup({
-      runner_modules = {
-        "test-samurai.runners.lua-plenary",
-      },
-    })
-
-    local bufnr = mkbuf("/tmp/project/tests/test_samurai_core_spec_unique_5_spec.lua", "lua")
-
-    local runner = require("test-samurai.core").get_runner_for_buf(bufnr)
-    assert.is_not_nil(runner)
-    assert.equals("lua-plenary", runner.name)
-  end)
-end)
diff --git a/tests/test_samurai_output_spec.lua b/tests/test_samurai_output_spec.lua
index d61b48e..abf5e5c 100644
--- a/tests/test_samurai_output_spec.lua
+++ b/tests/test_samurai_output_spec.lua
@@ -76,4 +76,157 @@ describe("test-samurai public API", function()
 
     assert.is_true(called)
   end)
+
+  it("delegates test_failed_only to core.run_failed_only", function()
+    local called = false
+    local orig = core.run_failed_only
+
+    core.run_failed_only = function()
+      called = true
+    end
+
+    test_samurai.test_failed_only()
+
+    core.run_failed_only = orig
+
+    assert.is_true(called)
+  end)
+end)
+
+describe("test-samurai output formatting", function()
+  before_each(function()
+    test_samurai.setup()
+  end)
+
+  it("formats JSON output as PASS/FAIL lines", function()
+    local json = vim.json.encode({
+      testResults = {
+        {
+          assertionResults = {
+            { status = "passed", title = "inner 1", fullName = "outer inner 1" },
+            { status = "skipped", title = "inner skip", fullName = "outer inner skip" },
+            { status = "failed", title = "inner 2", fullName = "outer inner 2" },
+          },
+        },
+      },
+    })
+
+    local orig_jobstart = vim.fn.jobstart
+    vim.fn.jobstart = function(_cmd, opts)
+      if opts and opts.on_stdout then
+        opts.on_stdout(1, { json }, nil)
+      end
+      if opts and opts.on_exit then
+        opts.on_exit(1, 1, nil)
+      end
+      return 1
+    end
+
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_buf_set_name(bufnr, "/tmp/output_format.test.ts")
+    vim.bo[bufnr].filetype = "typescript"
+    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, {
+      'describe("outer", function() {',
+      '  it("inner 1", function() {',
+      "    -- inside 1",
+      "  })",
+      "",
+      '  it("inner 2", function() {',
+      "    -- inside 2",
+      "  })",
+      "})",
+    })
+
+    vim.api.nvim_set_current_buf(bufnr)
+    vim.api.nvim_win_set_cursor(0, { 7, 0 })
+
+    core.run_nearest()
+
+    local out_buf = vim.api.nvim_get_current_buf()
+    local lines = vim.api.nvim_buf_get_lines(out_buf, 0, -1, false)
+
+    vim.fn.jobstart = orig_jobstart
+
+    local has_pass = false
+    local has_skip = false
+    local has_fail = false
+    for _, line in ipairs(lines) do
+      if line == "[ PASS ] - outer inner 1" then
+        has_pass = true
+      elseif line == "[ SKIP ] - outer inner skip" then
+        has_skip = true
+      elseif line == "[ FAIL ] - outer inner 2" then
+        has_fail = true
+      end
+    end
+    assert.is_true(has_pass)
+    assert.is_true(has_skip)
+    assert.is_true(has_fail)
+  end)
+
+  it("formats TAP output as PASS/FAIL lines", function()
+    test_samurai.setup({
+      runner_modules = {
+        "test-samurai.runners.js-vitest",
+      },
+    })
+
+    local orig_jobstart = vim.fn.jobstart
+    vim.fn.jobstart = function(_cmd, opts)
+      if opts and opts.on_stdout then
+        opts.on_stdout(1, {
+          "TAP version 13",
+          "1..2",
+          "ok 1 - outer inner 1 # time=1.00ms",
+          "ok 2 - outer inner skip # SKIP not now",
+          "not ok 2 - outer inner 2 # time=2.00ms",
+        }, nil)
+      end
+      if opts and opts.on_exit then
+        opts.on_exit(1, 1, nil)
+      end
+      return 1
+    end
+
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_buf_set_name(bufnr, "/tmp/output_format.tap.test.ts")
+    vim.bo[bufnr].filetype = "typescript"
+    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, {
+      'describe("outer", function() {',
+      '  it("inner 1", function() {',
+      "    -- inside 1",
+      "  })",
+      "",
+      '  it("inner 2", function() {',
+      "    -- inside 2",
+      "  })",
+      "})",
+    })
+
+    vim.api.nvim_set_current_buf(bufnr)
+    vim.api.nvim_win_set_cursor(0, { 7, 0 })
+
+    core.run_nearest()
+
+    local out_buf = vim.api.nvim_get_current_buf()
+    local lines = vim.api.nvim_buf_get_lines(out_buf, 0, -1, false)
+
+    vim.fn.jobstart = orig_jobstart
+
+    local has_pass = false
+    local has_skip = false
+    local has_fail = false
+    for _, line in ipairs(lines) do
+      if line == "[ PASS ] - outer inner 1" then
+        has_pass = true
+      elseif line == "[ SKIP ] - outer inner skip" then
+        has_skip = true
+      elseif line == "[ FAIL ] - outer inner 2" then
+        has_fail = true
+      end
+    end
+    assert.is_true(has_pass)
+    assert.is_true(has_skip)
+    assert.is_true(has_fail)
+  end)
 end)