diff --git a/src/fennel-ls.fnl b/src/fennel-ls.fnl
index 3316961..dcce084 100644
--- a/src/fennel-ls.fnl
+++ b/src/fennel-ls.fnl
@@ -10,6 +10,7 @@
                                     :method "initialize"
                                     :params {:capabilities {:general {:positionEncodings [:utf-8]}}
                                              :clientInfo {:name "fennel-ls"}
+                                             ; " don't think this is a valid URI, but I want to operate in the current directory
                                              :rootUri "file://."}}))]
     (var should-err? false)
     (each [_ filename (ipairs filenames)]
diff --git a/src/fennel-ls/diagnostics.fnl b/src/fennel-ls/diagnostics.fnl
index 7f4cf0d..7470e3c 100644
--- a/src/fennel-ls/diagnostics.fnl
+++ b/src/fennel-ls/diagnostics.fnl
@@ -9,6 +9,10 @@ the `file.diagnostics` field, filling it with diagnostics."
 (local {:scopes {:global {: specials}}}
   (require :fennel.compiler))
 
+(local diagnostic-mt {:__json_exclude_keys {:quickfix true}})
+(fn diagnostic [self]
+  (setmetatable self diagnostic-mt))
+
 (local ops {"+" 1 "-" 1 "*" 1 "/" 1 "//" 1 "%" 1 "^" 1 ">" 1 "<" 1 ">=" 1 "<=" 1 "=" 1 "not=" 1 ".." 1 "." 1 "and" 1 "or" 1 "band" 1 "bor" 1 "bxor" 1 "bnot" 1 "lshift" 1 "rshift" 1})
 (fn special? [item]
   (and (sym? item)
@@ -28,11 +32,14 @@ the `file.diagnostics` field, filling it with diagnostics."
                             &until reference]
                  (or (= ref.ref-type :read)
                      (= ref.ref-type :mutate)))))
-    {:range (message.ast->range self file symbol)
-     :message (.. "unused definition: " (tostring symbol))
-     :severity message.severity.WARN
-     :code 301
-     :codeDescription "unused-definition"}))
+    (diagnostic
+      {:range (message.ast->range self file symbol)
+       :message (.. "unused definition: " (tostring symbol))
+       :severity message.severity.WARN
+       :code 301
+       :codeDescription "unused-definition"
+       :quickfix #[{:range (message.ast->range symbol)
+                    :newText (.. "_" (tostring symbol))}]})))
 
 (λ unknown-module-field [self file]
   "any multisym whose definition can't be found through a (require) call"
@@ -73,15 +80,21 @@ the `file.diagnostics` field, filling it with diagnostics."
                  (sym? (. last-item 1) :table.unpack))
              (. file.lexical last-item)
              (. file.lexical call))
-     {:range (message.ast->range self file last-item)
-      :message (.. "faulty unpack call: " (tostring op) " isn't variadic at runtime."
-                   (if (sym? op "..")
-                     (let [unpackme (view (. last-item 2))]
-                       (.. " Use (table.concat " unpackme ") instead of (.. (unpack " unpackme "))"))
-                     (.. " Use a loop when you have a dynamic number of arguments to (" (tostring op) ")")))
-      :severity message.severity.WARN
-      :code 304
-      :codeDescription "bad-unpack"})))
+      (diagnostic
+        {:range (message.ast->range self file last-item)
+         :message (.. "faulty unpack call: " (tostring op) " isn't variadic at runtime."
+                      (if (sym? op "..")
+                        (let [unpackme (view (. last-item 2))]
+                          (.. " Use (table.concat " unpackme ") instead of (.. (unpack " unpackme "))"))
+                        (.. " Use a loop when you have a dynamic number of arguments to (" (tostring op) ")")))
+         :severity message.severity.WARN
+         :code 304
+         :codeDescription "bad-unpack"
+         :quickfix (if (and (= (length call) 2)
+                            (= (length (. call 2)) 2)
+                            (sym? op ".."))
+                     #[{:range (message.ast->range self file call)
+                        :newText (.. "(table.concat " (view (. call 2 2)) ")")}])}))))
 
 (λ var-never-set [self file symbol definition]
   (if (and definition.var? (not definition.var-set) (. file.lexical symbol))
@@ -94,15 +107,23 @@ the `file.diagnostics` field, filling it with diagnostics."
 (local op-identity-value {:+ 0 :* 1 :and true :or false :band -1 :bor 0 :.. ""})
 (λ op-with-no-arguments [self file op call]
   "A call like (+) that could be replaced with a literal"
-  (if (and (op? op)
-           (not (. call 2))
-           (. file.lexical call)
-           (not= nil (. op-identity-value (tostring op))))
-    {:range  (message.ast->range self file call)
-     :message (.. "write " (view (. op-identity-value (tostring op))) " instead of (" (tostring op) ")")
-     :severity message.severity.WARN
-     :code 306
-     :codeDescription "op-with-no-arguments"}))
+  (let [identity (. op-identity-value (tostring op))]
+    (if (and (op? op)
+             (not (. call 2))
+             (. file.lexical call)
+             (not= nil identity))
+      (diagnostic
+        {:range  (message.ast->range self file call)
+         :message (.. "write " (view identity) " instead of (" (tostring op) ")")
+         :severity message.severity.WARN
+         :code 306
+         :codeDescription "op-with-no-arguments"
+         :quickfix #[{:range (message.ast->range self file call)
+                      :newText (view identity)}]}))))
+
+; (fn quickfix.op-with-no-arguments [item]
+;   {:range item.range
+;    :newText (tostring item.data)})
 
 (λ multival-in-middle-of-call [self file fun call arg index]
   "generally, values and unpack are signs that the user is trying to do
diff --git a/src/fennel-ls/handlers.fnl b/src/fennel-ls/handlers.fnl
index 648ffe1..255f4ee 100644
--- a/src/fennel-ls/handlers.fnl
+++ b/src/fennel-ls/handlers.fnl
@@ -11,7 +11,6 @@ Every time the client sends a message, it gets handled by a function in the corr
 (local language (require :fennel-ls.language))
 (local formatter (require :fennel-ls.formatter))
 (local utils (require :fennel-ls.utils))
-
 (local fennel (require :fennel))
 
 (local requests [])
@@ -33,7 +32,7 @@ Every time the client sends a message, it gets handled by a function in the corr
    :referencesProvider {:workDoneProgress false}
    ;; :documentHighlightProvider nil
    ;; :documentSymbolProvider nil
-   ;; :codeActionProvider nil
+   :codeActionProvider {:workDoneProgress false}
    ;; :codeLensProvider nil
    ;; :documentLinkProvider nil
    ;; :colorProvider nil
@@ -229,6 +228,23 @@ Every time the client sends a message, it gets handled by a function in the corr
         {:changes {definition.file.uri usages}})
       (catch _ nil))))
 
+(fn pos<= [pos-1 pos-2]
+  (or (< pos-1.line pos-2.line)
+      (and (= pos-1.line pos-2.line)
+           (<= pos-1.character pos-2.character))))
+
+(fn overlap? [range-1 range-2]
+  (and (pos<= range-1.start range-2.end)
+       (pos<= range-2.start range-1.end)))
+
+(λ requests.textDocument/codeAction [self send {: range :textDocument {: uri} &as params}]
+  (let [file (state.get-by-uri self uri)]
+    (icollect [_ diagnostic (ipairs file.diagnostics)]
+      (if (and (overlap? diagnostic.range range)
+               diagnostic.quickfix)
+        {:title diagnostic.codeDescription
+         :edit {:changes {uri (diagnostic.quickfix)}}}))))
+
 (λ notifications.textDocument/didChange [self send {: contentChanges :textDocument {: uri}}]
   (local file (state.get-by-uri self uri))
   (state.set-uri-contents self uri (utils.apply-changes file.text contentChanges self.position-encoding))
@@ -243,12 +259,12 @@ Every time the client sends a message, it gets handled by a function in the corr
 
 (λ notifications.textDocument/didSave [self send {:textDocument {: uri}}]
   ;; TODO be careful about which modules need to be recomputed, and also eagerly flush existing files
-  (tset (require :fennel) :macro-loaded []))
+  (set fennel.macro-loaded []))
 
 (λ notifications.textDocument/didClose [self send {:textDocument {: uri}}]
   (local file (state.get-by-uri self uri))
   (set file.open? false)
-  (tset (require :fennel) :macro-loaded [])
+  (set fennel.macro-loaded [])
   ;; TODO only reload from disk if we didn't get a didSave, instead of always
   (state.flush-uri self uri))
 
diff --git a/test/code-action.fnl b/test/code-action.fnl
new file mode 100644
index 0000000..fae02ba
--- /dev/null
+++ b/test/code-action.fnl
@@ -0,0 +1,15 @@
+(local _faith (require :faith))
+(local {: view} (require :fennel))
+(local {: create-client-with-files} (require :test.utils))
+
+(fn check [file-contents]
+  (let [{: self : uri :locations [range]} (create-client-with-files file-contents)
+        response (self:code-action uri range.range)]
+;;    (print "hello" (view response))))
+      nil))
+
+(fn test-thing []
+  (check "(+====)"
+         "op-with-no-arguments"))
+
+{: test-thing}
diff --git a/test/init.fnl b/test/init.fnl
index 7e8d0f2..9761b51 100644
--- a/test/init.fnl
+++ b/test/init.fnl
@@ -21,5 +21,6 @@
    :test.completion
    :test.references
    :test.diagnostic
+   :test.code-action
    :test.rename
    :test.misc])
diff --git a/test/utils/client.fnl b/test/utils/client.fnl
index d858d7e..6b3c858 100644
--- a/test/utils/client.fnl
+++ b/test/utils/client.fnl
@@ -86,6 +86,13 @@
       :textDocument {:uri file}
       : newName})))
 
+(fn code-action [self file range]
+  (dispatch.handle* self.server
+    (message.create-request (next-id! self) :textDocument/codeAction
+     {: range
+      :textDocument {:uri file}
+      :context {:diagnostics []}})))
+
 (set mt.__index
      {: open-file!
       : pretend-this-file-exists!
@@ -93,7 +100,8 @@
       : definition
       : hover
       : references
-      : rename})
+      : rename
+      : code-action})
 
 {: create-client
  : default-encoding