diff --git a/infer/src/quandary/QuandarySummary.ml b/infer/src/quandary/QuandarySummary.ml
new file mode 100644
index 000000000..e481bebbd
--- /dev/null
+++ b/infer/src/quandary/QuandarySummary.ml
@@ -0,0 +1,113 @@
+(*
+ * Copyright (c) 2016 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+
+(** summary type for Quandary taint analysis *)
+
+open! Utils
+
+module F = Format
+module L = Logging
+
+type input =
+  | In_formal of int * AccessPath.t
+  (** input flows via parameter at given index at offset in given access path *)
+  | In_global of AccessPath.t
+  (** input flows from global at offset in given access path *)
+  | In_empty
+  (** no input value *)
+
+type output =
+  | Out_formal of int * AccessPath.t
+  (** output flows into parameter at given index at offset in given access path *)
+  | Out_global of AccessPath.t
+  (** output flows into global at offset in given access path *)
+  | Out_return of AccessPath.t
+  (** output flows into return value at offset in given access path *)
+
+(** enumeration of all the different trace types that are possible (just Java, for now). needed
+    because we can't functorize Specs.summary's *)
+type summary_trace =
+  | Java of JavaTrace.t
+  | Unknown
+
+(** input-output summary for a pair of values. intuitively, read it as
+    "if [input] is associated with trace T before the call, then [output] is
+    associated with trace (T + [output_trace]) after the call" (where `+` denotes trace
+    concatenation). *)
+type in_out_summary =
+  {
+    input : input;
+    output : output;
+    output_trace : summary_trace;
+  }
+
+type t = in_out_summary list
+
+module type Trace = sig
+  include Trace.S
+
+  val to_summary_trace : t -> summary_trace
+
+  val of_summary_trace : summary_trace -> t
+end
+
+let make_formal_input index access_path =
+  In_formal (index, access_path)
+
+let make_global_input access_path =
+  In_global access_path
+
+let empty_input = In_empty
+
+let make_formal_output index access_path =
+  Out_formal (index, access_path)
+
+let make_global_output access_path =
+  Out_global access_path
+
+let make_return_output access_path =
+  Out_return access_path
+
+let make_in_out_summary input output output_trace =
+  { input; output; output_trace; }
+
+let pp_trace fmt = function
+  | Java trace -> JavaTrace.pp fmt trace
+  | Unknown -> assert false
+
+let pp_input fmt = function
+  | In_formal (index, access_path) -> F.fprintf fmt "%a (formal %d)" AccessPath.pp access_path index
+  | In_global access_path -> F.fprintf fmt "%a (global)" AccessPath.pp access_path
+  | In_empty -> F.fprintf fmt "_"
+
+let pp_output fmt = function
+  | Out_formal (index, access_path) ->
+      F.fprintf fmt "%a (formal %d)" AccessPath.pp access_path index
+  | Out_global access_path ->
+      F.fprintf fmt "%a (global)" AccessPath.pp access_path
+  | Out_return access_path ->
+      F.fprintf fmt "%a (return)" AccessPath.pp access_path
+
+let pp_in_out_summary fmt summary =
+  match summary.input with
+  | In_empty ->
+      F.fprintf fmt
+        "%a => (%a, %a)"
+        pp_input summary.input
+        pp_output summary.output
+        pp_trace summary.output_trace
+  | In_formal _ | In_global _ ->
+      F.fprintf fmt
+        "(%a, T) => (%a, T :: %a)"
+        pp_input summary.input
+        pp_output summary.output
+        pp_trace summary.output_trace
+
+let pp fmt t =
+  PrettyPrintable.pp_collection ~pp_item:pp_in_out_summary fmt t
diff --git a/infer/src/quandary/QuandarySummary.mli b/infer/src/quandary/QuandarySummary.mli
new file mode 100644
index 000000000..38c9af9eb
--- /dev/null
+++ b/infer/src/quandary/QuandarySummary.mli
@@ -0,0 +1,83 @@
+(*
+ * Copyright (c) 2016 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+
+
+(** summary type for Quandary taint analysis *)
+
+module F = Format
+
+type input =
+  private
+  | In_formal of int * AccessPath.t
+  (** input flows via parameter at given index at offset in given access path *)
+  | In_global of AccessPath.t
+  (** input flows from global at offset in given access path *)
+  | In_empty
+  (** no input value *)
+
+type output =
+  private
+  | Out_formal of int * AccessPath.t
+  (** output flows into parameter at given index at offset in given access path *)
+  | Out_global of AccessPath.t
+  (** output flows into global at offset in given access path *)
+  | Out_return of AccessPath.t
+  (** output flows into return value at offset in given access path *)
+
+(** enumeration of all the different trace types that are possible (just Java, for now). needed
+    because we can't functorize Specs.summary's *)
+type summary_trace =
+  | Java of JavaTrace.t
+  | Unknown
+
+(** input-output summary for a pair of values. intuitively, read it as
+    "if [input] is associated with trace T before the call, then [output] is
+    associated with trace (T + [output_trace]) after the call" (where `+` denotes trace
+    concatenation). *)
+type in_out_summary =
+  private
+  {
+    input : input;
+    output : output;
+    output_trace : summary_trace;
+  }
+
+type t = in_out_summary list
+
+module type Trace = sig
+  include Trace.S
+
+  val to_summary_trace : t -> summary_trace
+
+  val of_summary_trace : summary_trace -> t
+end
+
+val make_formal_input : int -> AccessPath.t -> input
+
+val make_global_input : AccessPath.t -> input
+
+val empty_input : input
+
+val make_formal_output : int -> AccessPath.t -> output
+
+val make_global_output : AccessPath.t -> output
+
+val make_return_output : AccessPath.t -> output
+
+val make_in_out_summary : input -> output -> summary_trace -> in_out_summary
+
+val pp_trace : F.formatter -> summary_trace -> unit
+
+val pp_input : F.formatter -> input -> unit
+
+val pp_output : F.formatter -> output -> unit
+
+val pp_in_out_summary : F.formatter -> in_out_summary -> unit
+
+val pp : F.formatter -> t -> unit