diff --git a/README.md b/README.md
index d4068e1..63d02ba 100644
--- a/README.md
+++ b/README.md
@@ -111,7 +111,7 @@ Built-in provider names:
 - `:PeekstackSaveSession` — save current stack (persist enabled)
 - `:PeekstackRestoreSession` — restore a saved session
 - `:PeekstackListSessions` — list all saved sessions
-- `:PeekstackDeleteSession {name}` — delete a saved session by name
+- `:PeekstackDeleteSession [name]` — delete a saved session (prompts to select when no name is given)
 - `:PeekstackRestorePopup` — restore the last closed popup (undo close)
 - `:PeekstackRestoreAllPopups` — restore all closed popups
 - `:PeekstackCloseAll` — close all popups in the current stack
diff --git a/doc/peekstack.txt b/doc/peekstack.txt
index d8e2e94..7aaec7e 100644
--- a/doc/peekstack.txt
+++ b/doc/peekstack.txt
@@ -279,8 +279,9 @@ Commands are registered after `setup()` is called.
 :PeekstackListSessions                       *:PeekstackListSessions*
     List all saved sessions. Select one to view its summary.
 
-:PeekstackDeleteSession {name}               *:PeekstackDeleteSession*
-    Delete a saved session by name. Prompts for confirmation.
+:PeekstackDeleteSession [name]               *:PeekstackDeleteSession*
+    Delete a saved session. Prompts for confirmation before deleting. When
+    no name is given, prompts to select one from the saved sessions.
 
 :PeekstackRestorePopup                        *:PeekstackRestorePopup*
     Restore the last closed popup from history (undo close).
diff --git a/lua/peekstack/commands.lua b/lua/peekstack/commands.lua
index 9b3a495..59c5ffd 100644
--- a/lua/peekstack/commands.lua
+++ b/lua/peekstack/commands.lua
@@ -46,6 +46,37 @@ local function list_session_names()
   return names
 end
 
+---Keep only candidates whose prefix matches the current argument.
+---Lua command completion behaves like `customlist`, so Neovim does not filter
+---the returned list against `ArgLead` for us.
+---@param candidates string[]
+---@param arg_lead string
+---@return string[]
+local function filter_by_prefix(candidates, arg_lead)
+  if not arg_lead or arg_lead == "" then
+    return candidates
+  end
+  return vim.tbl_filter(function(candidate)
+    return vim.startswith(candidate, arg_lead)
+  end, candidates)
+end
+
+---@param arg_lead string
+---@return string[]
+local function complete_session_names(arg_lead)
+  return filter_by_prefix(list_session_names(), arg_lead)
+end
+
+---Confirm and delete a named session.
+---@param name string
+local function confirm_delete_session(name)
+  vim.ui.select({ "Yes", "No" }, { prompt = "Delete session '" .. name .. "'?" }, function(choice)
+    if choice == "Yes" then
+      require("peekstack.persist").delete_session(name)
+    end
+  end)
+end
+
 function M.setup()
   if loaded then
     return
@@ -80,7 +111,7 @@ function M.setup()
     require("peekstack.persist").restore(name)
   end, {
     nargs = "?",
-    complete = list_session_names,
+    complete = complete_session_names,
   })
 
   vim.api.nvim_create_user_command("PeekstackListSessions", function()
@@ -115,19 +146,31 @@ function M.setup()
   end, {})
 
   vim.api.nvim_create_user_command("PeekstackDeleteSession", function(opts)
-    local name = opts.args
-    if not name or name == "" then
-      notify.warn("Usage: PeekstackDeleteSession <name>")
+    local name = opts.args and opts.args ~= "" and opts.args or nil
+    if name then
+      confirm_delete_session(name)
       return
     end
-    vim.ui.select({ "Yes", "No" }, { prompt = "Delete session '" .. name .. "'?" }, function(choice)
-      if choice == "Yes" then
-        require("peekstack.persist").delete_session(name)
-      end
-    end)
+
+    require("peekstack.persist").list_sessions({
+      on_done = function(sessions)
+        local names = vim.tbl_keys(sessions)
+        table.sort(names)
+        if #names == 0 then
+          notify.info("No saved sessions")
+          return
+        end
+        vim.ui.select(names, { prompt = "Delete session" }, function(selected)
+          if not selected then
+            return
+          end
+          confirm_delete_session(selected)
+        end)
+      end,
+    })
   end, {
-    nargs = 1,
-    complete = list_session_names,
+    nargs = "?",
+    complete = complete_session_names,
   })
 
   vim.api.nvim_create_user_command("PeekstackRestorePopup", function()
@@ -201,8 +244,8 @@ function M.setup()
     require("peekstack").peek(provider, { mode = "quick" })
   end, {
     nargs = "?",
-    complete = function()
-      return require("peekstack").list_providers()
+    complete = function(arg_lead)
+      return filter_by_prefix(require("peekstack").list_providers(), arg_lead)
     end,
   })
 end
diff --git a/tests/commands_spec.lua b/tests/commands_spec.lua
index befc4d2..3902875 100644
--- a/tests/commands_spec.lua
+++ b/tests/commands_spec.lua
@@ -4,6 +4,7 @@ describe("peekstack.commands", function()
   local peekstack = require("peekstack")
   local persist = require("peekstack.persist")
   local original_list_sessions = nil
+  local original_delete_session = nil
   local original_select = nil
   local original_notify = nil
   local original_strftime = nil
@@ -12,6 +13,7 @@ describe("peekstack.commands", function()
     config.setup({})
     commands._reset()
     original_list_sessions = persist.list_sessions
+    original_delete_session = persist.delete_session
     original_select = vim.ui.select
     original_notify = vim.notify
     original_strftime = vim.fn.strftime
@@ -22,6 +24,9 @@ describe("peekstack.commands", function()
     if original_list_sessions then
       persist.list_sessions = original_list_sessions
     end
+    if original_delete_session then
+      persist.delete_session = original_delete_session
+    end
     if original_select then
       vim.ui.select = original_select
     end
@@ -54,6 +59,121 @@ describe("peekstack.commands", function()
     assert.is_false(called_with_opts)
   end)
 
+  it("filters session completion by ArgLead prefix", function()
+    persist.list_sessions = function()
+      return {
+        alpha = { items = {}, meta = { created_at = 1, updated_at = 1 } },
+        alpine = { items = {}, meta = { created_at = 1, updated_at = 1 } },
+        beta = { items = {}, meta = { created_at = 1, updated_at = 1 } },
+      }
+    end
+
+    commands.setup()
+    local names = vim.fn.getcompletion("PeekstackRestoreSession al", "cmdline")
+    table.sort(names)
+
+    assert.same({ "alpha", "alpine" }, names)
+  end)
+
+  it("filters quick peek completion by ArgLead prefix", function()
+    peekstack.setup({})
+    local names = vim.fn.getcompletion("PeekstackQuickPeek lsp.d", "cmdline")
+
+    assert.is_true(#names > 0)
+    for _, name in ipairs(names) do
+      assert.is_true(vim.startswith(name, "lsp.d"))
+    end
+    assert.is_true(vim.list_contains(names, "lsp.definition"))
+    assert.is_true(vim.list_contains(names, "lsp.declaration"))
+    assert.is_false(vim.list_contains(names, "lsp.references"))
+  end)
+
+  it("prompts to select a session when delete is invoked without a name", function()
+    local deleted = nil
+    local select_items = nil
+    persist.list_sessions = function(opts)
+      assert.is_truthy(opts)
+      assert.is_truthy(opts.on_done)
+      opts.on_done({
+        beta = { items = {}, meta = { created_at = 1, updated_at = 1 } },
+        alpha = { items = {}, meta = { created_at = 1, updated_at = 1 } },
+      })
+      return {}
+    end
+    persist.delete_session = function(name)
+      deleted = name
+    end
+
+    vim.ui.select = function(items, opts, on_choice)
+      if opts.prompt == "Delete session" then
+        select_items = vim.deepcopy(items)
+        on_choice("beta")
+        return
+      end
+      on_choice("Yes")
+    end
+
+    commands.setup()
+    vim.api.nvim_cmd({ cmd = "PeekstackDeleteSession" }, {})
+
+    assert.same({ "alpha", "beta" }, select_items)
+    assert.equals("beta", deleted)
+  end)
+
+  it("notifies when no sessions exist on nameless delete", function()
+    local deleted = false
+    local messages = {}
+    persist.list_sessions = function(opts)
+      opts.on_done({})
+      return {}
+    end
+    persist.delete_session = function()
+      deleted = true
+    end
+    vim.notify = function(msg)
+      table.insert(messages, msg)
+    end
+
+    commands.setup()
+    vim.api.nvim_cmd({ cmd = "PeekstackDeleteSession" }, {})
+
+    assert.is_true(vim.list_contains(messages, "[peekstack] No saved sessions"))
+    assert.is_false(deleted)
+  end)
+
+  it("confirms before deleting a named session", function()
+    local deleted = nil
+    local prompt = nil
+    persist.delete_session = function(name)
+      deleted = name
+    end
+    vim.ui.select = function(_items, opts, on_choice)
+      prompt = opts.prompt
+      on_choice("Yes")
+    end
+
+    commands.setup()
+    vim.api.nvim_cmd({ cmd = "PeekstackDeleteSession", args = { "alpha" } }, {})
+
+    assert.equals("Delete session 'alpha'?", prompt)
+    assert.equals("alpha", deleted)
+  end)
+
+  it("does not delete a named session when confirmation is declined", function()
+    local deleted = false
+    persist.delete_session = function()
+      deleted = true
+    end
+    vim.ui.select = function(_items, _opts, on_choice)
+      on_choice("No")
+    end
+
+    commands.setup()
+    vim.api.nvim_cmd({ cmd = "PeekstackDeleteSession", args = { "alpha" } }, {})
+
+    assert.is_false(deleted)
+  end)
+
   it("handles missing session meta in list command", function()
     local prompts = {}
     persist.list_sessions = function(opts)