diff --git a/src/base/Sidekick_base.ml b/src/base/Sidekick_base.ml
index 5d7df622..d4cf4ed7 100644
--- a/src/base/Sidekick_base.ml
+++ b/src/base/Sidekick_base.ml
@@ -42,3 +42,14 @@ let th_bool_static : Solver.theory = Th_bool.theory_static
 let th_data : Solver.theory = Th_data.theory
 let th_lra : Solver.theory = Th_lra.theory
 let th_ty_unin : Solver.theory = Th_ty_unin.theory
+
+(** All constant decoders *)
+let const_decoders =
+  List.flatten
+    [
+      Uconst.const_decoders;
+      LRA_term.const_decoders;
+      Ty.const_decoders;
+      (* TODO Th_data *)
+      Form.const_decoders;
+    ]
diff --git a/src/base/Uconst.ml b/src/base/Uconst.ml
index b295f67e..37478704 100644
--- a/src/base/Uconst.ml
+++ b/src/base/Uconst.ml
@@ -42,7 +42,7 @@ let const_decoders : Const.decoders =
       ops,
       Ser_decode.(
         fun dec_t ->
-          let+ uc_id = ID.deser and+ uc_ty = dec_t in
+          let+ uc_id, uc_ty = tup2 ID.deser dec_t in
           Uconst { uc_id; uc_ty }) );
   ]
 
diff --git a/src/core/t_trace_reader.ml b/src/core/t_trace_reader.ml
index 4e1df71f..a81e1948 100644
--- a/src/core/t_trace_reader.ml
+++ b/src/core/t_trace_reader.ml
@@ -9,7 +9,7 @@ type const_decoders = Const.decoders
 type t = {
   tst: Term.store;
   src: Tr.Source.t;
-  cache: (Term.t, string) result ID_cache.t;
+  cache: (Term.t, Dec.Error.t) result ID_cache.t;
   mutable const_decode:
     (Const.Ops.t * (Term.t Dec.t -> Const.view Dec.t)) Util.Str_map.t;
       (** tag -> const decoder *)
@@ -75,22 +75,32 @@ let decode_term (self : t) ~read_subterm ~tag : Term.t Dec.t =
         let+ c_view = reflect_or_fail (c_dec read_subterm) view in
         let const = Const.make c_view ops ~ty in
         Term.const self.tst const))
-  | "Tf@" -> assert false (* TODO *)
+  | "Tf@" ->
+    Dec.(
+      let+ f = dict_field "f" read_subterm
+      and+ l = dict_field "l" (list read_subterm)
+      and+ acc0 = dict_field "a0" read_subterm in
+      Term.app_fold self.tst ~f l ~acc0)
   | _ -> Dec.failf "unknown tag %S for a term" tag
 
-let rec read_term (self : t) (id : term_ref) : _ result =
+let rec read_term_err (self : t) (id : term_ref) : _ result =
   (* decoder for subterms *)
   let read_subterm : Term.t Dec.t =
     Dec.(
       let* id = int in
-      match read_term self id with
-      | Ok x -> return x
-      | Error e -> fail e)
+      return_result_err @@ read_term_err self id)
   in
 
   ID_cache.get self.cache id ~compute:(fun id ->
       match Tr.Source.get_entry self.src id with
-      | None -> Error (Printf.sprintf "invalid entry: %d" id)
+      | None ->
+        Error
+          (Dec.Error.of_string
+             (Printf.sprintf "invalid entry: %d" id)
+             (Ser_value.int id))
       | Some (tag, v) ->
         let dec = decode_term self ~tag ~read_subterm in
-        Dec.run dec v |> Result.map_error Dec.Error.to_string)
+        Dec.run dec v)
+
+let read_term self id =
+  Result.map_error Dec.Error.to_string @@ read_term_err self id
diff --git a/src/core/t_trace_reader.mli b/src/core/t_trace_reader.mli
index 3d31ca65..22d919bc 100644
--- a/src/core/t_trace_reader.mli
+++ b/src/core/t_trace_reader.mli
@@ -11,3 +11,4 @@ val create :
 
 val add_const_decoders : t -> const_decoders -> unit
 val read_term : t -> term_ref -> (Term.t, string) result
+val read_term_err : t -> term_ref -> (Term.t, Ser_decode.Error.t) result
diff --git a/src/core/t_tracer.ml b/src/core/t_tracer.ml
index cb9738e8..f712043e 100644
--- a/src/core/t_tracer.ml
+++ b/src/core/t_tracer.ml
@@ -42,7 +42,14 @@ let emit_term_ (self : state) (t : Term.t) =
             in
             V.dict_of_list fields )
         | T.E_app_fold { f; args; acc0 } ->
-          "Tf@", V.(list [ loop' f; list (List.map loop' args); loop' acc0 ])
+          ( "Tf@",
+            V.(
+              dict_of_list
+                [
+                  "f", loop' f;
+                  "l", list (List.map loop' args);
+                  "a0", loop' acc0;
+                ]) )
         | T.E_lam (name, ty, bod) ->
           "Tl", V.(list [ string name; loop' ty; loop' bod ])
         | T.E_pi (name, ty, bod) ->
diff --git a/src/main/dune b/src/main/dune
index 7b2db52b..7727142d 100644
--- a/src/main/dune
+++ b/src/main/dune
@@ -15,5 +15,6 @@
  (name show_trace)
  (modules show_trace)
  (modes native)
- (libraries containers sidekick.util sidekick.core sidekick.trace)
+ (libraries containers sidekick.util sidekick.core sidekick.trace
+   sidekick.smt-solver sidekick-base)
  (flags :standard -safe-string -color always -open Sidekick_util))
diff --git a/src/main/show_trace.ml b/src/main/show_trace.ml
index 0d941371..46d59efd 100644
--- a/src/main/show_trace.ml
+++ b/src/main/show_trace.ml
@@ -1,21 +1,43 @@
+open Sidekick_core
 open Sidekick_trace
+module Smt = Sidekick_smt_solver
 
-let show_file file : unit =
+let show_file ~dump file : unit =
   Log.debugf 1 (fun k -> k "(@[show-file %S@])" file);
   let src = Source.of_string_using_bencode @@ CCIO.File.read_exn file in
+  let tst = Term.Store.create () in
+
+  (* trace reader *)
+  let t_reader =
+    Smt.Trace_reader.create tst src
+      ~const_decoders:
+        [
+          Term.const_decoders; Box.const_decoders; Sidekick_base.const_decoders;
+        ]
+  in
+
   Source.iter_all src (fun i ~tag v ->
-      Format.printf "[%d]: %S %a@." i tag Sidekick_util.Ser_value.pp v)
+      Log.debugf 10 (fun k ->
+          k "(@[show-trace[%d]@ :tag %S@ :val %a@])" i tag Ser_value.pp v);
+      if dump then Format.printf "[%d]: %S %a@." i tag Ser_value.pp v;
+
+      match Smt.Trace_reader.decode t_reader ~tag v with
+      | Some e -> Fmt.printf "[%d]: %a@." i Smt.Trace_reader.pp_entry e
+      | None -> ())
 
 let () =
   let files = ref [] in
+  let dump = ref false in
   let opts =
     [
+      "--dump", Arg.Set dump, " dump each raw entry";
       ( "--bt",
         Arg.Unit (fun () -> Printexc.record_backtrace true),
         " enable backtraces" );
+      "-d", Arg.Int Log.set_debug, " debug level";
     ]
     |> Arg.align
   in
   Arg.parse opts (fun f -> files := f :: !files) "show_trace [file]+";
   let files = List.rev !files in
-  List.iter show_file files
+  List.iter (show_file ~dump:!dump) files
diff --git a/src/smt/Sidekick_smt_solver.ml b/src/smt/Sidekick_smt_solver.ml
index ea9cc2a6..b1452b9b 100644
--- a/src/smt/Sidekick_smt_solver.ml
+++ b/src/smt/Sidekick_smt_solver.ml
@@ -17,6 +17,7 @@ module Theory_id = Theory_id
 module Preprocess = Preprocess
 module Find_foreign = Find_foreign
 module Tracer = Tracer
+module Trace_reader = Trace_reader
 
 type theory = Theory.t
 type solver = Solver.t
diff --git a/src/smt/trace_reader.ml b/src/smt/trace_reader.ml
new file mode 100644
index 00000000..85ccf19c
--- /dev/null
+++ b/src/smt/trace_reader.ml
@@ -0,0 +1,55 @@
+open Sidekick_core
+module Tr = Sidekick_trace
+
+type entry = Assert of Term.t | Assert_clause of Lit.t list
+
+let pp_entry out = function
+  | Assert t -> Fmt.fprintf out "(@[assert@ %a@])" Term.pp t
+  | Assert_clause c ->
+    Fmt.fprintf out "(@[assert-c@ %a@])" (Fmt.Dump.list Lit.pp) c
+
+type t = { tst: Term.store; src: Tr.Source.t; t_dec: Term.Trace_reader.t }
+
+let create ?const_decoders tst src : t =
+  let t_dec = Term.Trace_reader.create ?const_decoders tst ~source:src in
+  { tst; src; t_dec }
+
+let add_const_decoders self c = Term.Trace_reader.add_const_decoders self.t_dec c
+
+let dec_t (self : t) =
+  Ser_decode.(
+    let* i = int in
+    return_result @@ Term.Trace_reader.read_term self.t_dec i)
+
+let dec_c (self : t) =
+  Ser_decode.(
+    let dec_lit =
+      let+ b, t = tup2 bool @@ dec_t self in
+      Lit.atom self.tst ~sign:b t
+    in
+    list dec_lit)
+
+let decode (self : t) ~tag v =
+  Log.debugf 30 (fun k ->
+      k "(@[trace-reader.decode@ :tag %S@ :val %a@])" tag Ser_value.pp v);
+  match tag with
+  | "Asst" ->
+    (match Ser_decode.(run (dec_t self) v) with
+    | Ok t -> Some (Assert t)
+    | Error err ->
+      Fmt.eprintf "cannot decode entry with tag %S:@ %a@." tag
+        Ser_decode.Error.pp err;
+      None)
+  | "AssC" ->
+    Ser_decode.(
+      (match run (dec_c self) v with
+      | Ok c -> Some (Assert_clause c)
+      | Error err ->
+        Fmt.eprintf "cannot decode entry with tag %S:@ %a@." tag
+          Ser_decode.Error.pp err;
+        None))
+  | _ -> None
+
+let decode_entry self id : _ option =
+  let tag, v = Tr.Source.get_entry_exn self.src id in
+  decode self ~tag v
diff --git a/src/smt/trace_reader.mli b/src/smt/trace_reader.mli
new file mode 100644
index 00000000..e26c9a2f
--- /dev/null
+++ b/src/smt/trace_reader.mli
@@ -0,0 +1,17 @@
+(** Read trace *)
+
+open Sidekick_core
+module Tr = Sidekick_trace
+
+type entry = Assert of Term.t | Assert_clause of Lit.t list
+
+val pp_entry : entry Fmt.printer
+
+type t
+
+val create :
+  ?const_decoders:Const.decoders list -> Term.store -> Tr.Source.t -> t
+
+val add_const_decoders : t -> Const.decoders -> unit
+val decode : t -> tag:string -> Ser_value.t -> entry option
+val decode_entry : t -> Tr.Entry_id.t -> entry option
diff --git a/src/smt/tracer.ml b/src/smt/tracer.ml
index 540b03a4..678e36f2 100644
--- a/src/smt/tracer.ml
+++ b/src/smt/tracer.ml
@@ -2,8 +2,6 @@ open Sidekick_core
 module Tr = Sidekick_trace
 module V = Ser_value
 
-type Tr.entry_view += Assert of Term.t | Assert_clause of Lit.t list
-
 class type t =
   object
     inherit Term.Tracer.t
diff --git a/src/smt/tracer.mli b/src/smt/tracer.mli
index bad089f2..ef8588a0 100644
--- a/src/smt/tracer.mli
+++ b/src/smt/tracer.mli
@@ -1,8 +1,6 @@
 open Sidekick_core
 module Tr = Sidekick_trace
 
-type Tr.entry_view += Assert of Term.t | Assert_clause of Lit.t list
-
 class type t =
   object
     inherit Term.Tracer.t
diff --git a/src/trace/sink.ml b/src/trace/sink.ml
index f35544c8..9365a7b8 100644
--- a/src/trace/sink.ml
+++ b/src/trace/sink.ml
@@ -24,18 +24,19 @@ let null : t =
   end)
 
 let of_out_channel_using_bencode (oc : out_channel) : t =
-  let id_ = ref 0 in
+  (* id: offset in the channel *)
+  let off = ref 0 in
   let buf = Buffer.create 128 in
   (module struct
     let emit ~tag (v : Ser_value.t) =
       assert (Buffer.length buf = 0);
-      let id = Entry_id.of_int_unsafe !id_ in
+      let id = Entry_id.of_int_unsafe !off in
       (* add tag+id around *)
       let v' = Ser_value.(list [ int id; string tag; v ]) in
-      incr id_;
       Sidekick_bencode.Encode.to_buffer buf v';
       Buffer.add_char buf '\n';
       Buffer.output_buffer oc buf;
+      off := !off + Buffer.length buf;
       Buffer.clear buf;
       id
   end)
diff --git a/src/util/ser_decode.ml b/src/util/ser_decode.ml
index 530537c3..4f21e289 100644
--- a/src/util/ser_decode.ml
+++ b/src/util/ser_decode.ml
@@ -8,10 +8,11 @@ module Error = struct
   type t = { msg: string; v: V.t; subs: t list }
 
   let mk ?(subs = []) msg v : t = { msg; v; subs }
+  let of_string s v : t = mk s v
 
   let pp out (self : t) =
     let rec pp out self =
-      Fmt.fprintf out "@[<v2>@[<2>%s@ in %a@]" self.msg V.pp self.v;
+      Fmt.fprintf out "@[<v2>@[<2>%s@ in value %a@]" self.msg V.pp self.v;
       List.iter
         (fun s -> Fmt.fprintf out "@ @[<2>sub-error:@ %a@]" pp s)
         self.subs;
@@ -28,10 +29,19 @@ type 'a t = { deser: V.t -> 'a } [@@unboxed]
 
 let[@inline] fail_ msg v = raise_notrace (Fail (Error.mk msg v))
 let[@inline] fail_e e = raise_notrace (Fail e)
+let fail_err e = { deser = (fun _ -> fail_e e) }
 let return x = { deser = (fun _ -> x) }
 let fail s = { deser = (fun v -> fail_ s v) }
 let failf fmt = Printf.ksprintf fail fmt
 
+let return_result = function
+  | Ok x -> return x
+  | Error s -> fail s
+
+let return_result_err = function
+  | Ok x -> return x
+  | Error e -> fail_err e
+
 let unwrap_opt msg = function
   | Some x -> return x
   | None -> fail msg
@@ -43,6 +53,8 @@ let bool =
     deser =
       (function
       | V.Bool b -> b
+      | V.Int 1 -> true
+      | V.Int 0 -> false
       | v -> fail_ "expected bool" v);
   }
 
diff --git a/src/util/ser_decode.mli b/src/util/ser_decode.mli
index 7f14f789..fff60b4d 100644
--- a/src/util/ser_decode.mli
+++ b/src/util/ser_decode.mli
@@ -9,6 +9,8 @@ module Error : sig
   include Sidekick_sigs.PRINT with type t := t
 
   val to_string : t -> string
+
+  val of_string : string -> Ser_value.t -> t
 end
 
 (** {2 Main combinators *)
@@ -20,8 +22,11 @@ val int : int t
 val bool : bool t
 val string : string t
 val return : 'a -> 'a t
+val return_result : ('a, string) result -> 'a t
+val return_result_err : ('a, Error.t) result -> 'a t
 val fail : string -> 'a t
 val failf : ('a, unit, string, 'b t) format4 -> 'a
+val fail_err : Error.t -> 'a t
 val unwrap_opt : string -> 'a option -> 'a t
 (** Unwrap option, or fail *)
 val any : Ser_value.t t