diff --git a/lua/peekstack/commands.lua b/lua/peekstack/commands.lua
index 9720369..af0902e 100644
--- a/lua/peekstack/commands.lua
+++ b/lua/peekstack/commands.lua
@@ -177,21 +177,7 @@ function M.setup()
   end, {
     nargs = "?",
     complete = function()
-      return {
-        "lsp.definition",
-        "lsp.implementation",
-        "lsp.references",
-        "lsp.type_definition",
-        "lsp.declaration",
-        "lsp.symbols_document",
-        "diagnostics.under_cursor",
-        "diagnostics.in_buffer",
-        "file.under_cursor",
-        "grep.search",
-        "marks.buffer",
-        "marks.global",
-        "marks.all",
-      }
+      return require("peekstack").list_providers()
     end,
   })
 end
diff --git a/lua/peekstack/init.lua b/lua/peekstack/init.lua
index f52bb52..3bef8ea 100644
--- a/lua/peekstack/init.lua
+++ b/lua/peekstack/init.lua
@@ -43,6 +43,13 @@ function M.register_provider(name, fn)
   providers[name] = fn
 end
 
+---@return string[]
+function M.list_providers()
+  local names = vim.tbl_keys(providers)
+  table.sort(names)
+  return names
+end
+
 ---@param name string
 ---@param fn PeekstackPicker
 function M.register_picker(name, fn)
diff --git a/tests/commands_spec.lua b/tests/commands_spec.lua
index e41cbaf..c6e37e7 100644
--- a/tests/commands_spec.lua
+++ b/tests/commands_spec.lua
@@ -1,6 +1,7 @@
 describe("peekstack.commands", function()
   local commands = require("peekstack.commands")
   local config = require("peekstack.config")
+  local peekstack = require("peekstack")
   local persist = require("peekstack.persist")
   local original_list_sessions = nil
   local original_select = nil
@@ -135,15 +136,37 @@ describe("peekstack.commands", function()
     assert.equals("alpha: 0 items (updated: formatted-time)", prompts[2])
   end)
 
-  it("includes extended providers in quick peek completion", function()
-    commands.setup()
+  it("uses registered providers for quick peek completion", function()
+    peekstack.setup({})
     local names = vim.fn.getcompletion("PeekstackQuickPeek ", "cmdline")
 
     assert.is_true(vim.list_contains(names, "lsp.declaration"))
     assert.is_true(vim.list_contains(names, "lsp.symbols_document"))
     assert.is_true(vim.list_contains(names, "diagnostics.in_buffer"))
+    assert.is_false(vim.list_contains(names, "marks.buffer"))
+    assert.is_false(vim.list_contains(names, "marks.global"))
+    assert.is_false(vim.list_contains(names, "marks.all"))
+  end)
+
+  it("reflects provider registration changes in quick peek completion", function()
+    peekstack.setup({
+      providers = {
+        marks = {
+          enable = true,
+        },
+      },
+    })
+
+    local names = vim.fn.getcompletion("PeekstackQuickPeek ", "cmdline")
     assert.is_true(vim.list_contains(names, "marks.buffer"))
     assert.is_true(vim.list_contains(names, "marks.global"))
     assert.is_true(vim.list_contains(names, "marks.all"))
+
+    peekstack.register_provider("custom.test", function(_ctx, cb)
+      cb({})
+    end)
+
+    names = vim.fn.getcompletion("PeekstackQuickPeek ", "cmdline")
+    assert.is_true(vim.list_contains(names, "custom.test"))
   end)
 end)