diff --git a/patronus/src/expr.rs b/patronus/src/expr.rs
index a2b60dc..f11ddf4 100644
--- a/patronus/src/expr.rs
+++ b/patronus/src/expr.rs
@@ -25,7 +25,7 @@ pub use parse::parse_expr;
 pub use serialize::SerializableIrNode;
 pub(crate) use serialize::{serialize_expr, serialize_expr_ref};
 pub(crate) use simplify::simplify;
-pub use simplify::simplify_single_expression;
+pub use simplify::{simplify_single_expression, Simplifier};
 pub use transform::simple_transform_expr;
 pub(crate) use transform::{do_transform_expr, ExprTransformMode};
 pub use types::{TypeCheck, TypeCheckError};
diff --git a/tools/simplify/src/main.rs b/tools/simplify/src/main.rs
index 92ce42d..35c0b24 100644
--- a/tools/simplify/src/main.rs
+++ b/tools/simplify/src/main.rs
@@ -5,7 +5,6 @@
 use clap::Parser;
 use patronus::expr::*;
 use patronus::smt::{parse_command, serialize_cmd, SmtCommand};
-use patronus::*;
 use rustc_hash::FxHashMap;
 use std::io::{BufRead, BufReader, BufWriter};
 use std::path::PathBuf;
@@ -16,6 +15,8 @@ use std::path::PathBuf;
 #[command(version)]
 #[command(about = "Parses a SMT file, simplifies it and writes the simplified version to an output file.", long_about = None)]
 struct Args {
+    #[arg(long)]
+    do_not_simplify: bool,
     #[arg(value_name = "INPUT", index = 1)]
     input_file: PathBuf,
     #[arg(value_name = "OUTPUT", index = 2)]
@@ -37,13 +38,34 @@ fn main() {
     // read and write commands
     let mut ctx = Context::default();
     let mut st = FxHashMap::default();
+    let mut simplifier = Simplifier::new(SparseExprMap::default());
     while let Some(cmd) =
         read_cmd(&mut in_reader, &mut ctx, &mut st).expect("failed to read command")
     {
+        let cmd = if args.do_not_simplify {
+            cmd
+        } else {
+            simplify(&mut ctx, &mut simplifier, cmd)
+        };
         serialize_cmd(&mut out, Some(&ctx), &cmd).expect("failed to write command");
     }
 }
 
+fn simplify<T: ExprMap<Option<ExprRef>>>(
+    ctx: &mut Context,
+    s: &mut Simplifier<T>,
+    cmd: SmtCommand,
+) -> SmtCommand {
+    match cmd {
+        SmtCommand::Assert(e) => SmtCommand::Assert(s.simplify(ctx, e)),
+        SmtCommand::DefineConst(sym, value) => SmtCommand::DefineConst(sym, s.simplify(ctx, value)),
+        SmtCommand::CheckSatAssuming(e) => {
+            SmtCommand::CheckSatAssuming(e.into_iter().map(|e| s.simplify(ctx, e)).collect())
+        }
+        other => other,
+    }
+}
+
 type SymbolTable = FxHashMap<String, ExprRef>;
 
 fn read_cmd(