diff --git a/crates/conjure-cp-cli/src/pretty.rs b/crates/conjure-cp-cli/src/pretty.rs
index 08dc5fa5b6..b9f5715b4f 100644
--- a/crates/conjure-cp-cli/src/pretty.rs
+++ b/crates/conjure-cp-cli/src/pretty.rs
@@ -3,7 +3,7 @@ use std::{path::PathBuf, sync::Arc};
 use anyhow::anyhow;
 use clap::ValueHint;
 
-use conjure_cp_cli::utils::testing::serialize_model;
+use conjure_cp_cli::utils::testing::{serialize_domains, serialize_model};
 
 use crate::cli::{GlobalArgs, LOGGING_HELP_HEADING};
 use crate::solve::{init_context, parse};
@@ -28,10 +28,11 @@ pub fn run_pretty_command(global_args: GlobalArgs, pretty_args: Args) -> anyhow:
     // Running the correct method to acquire pretty string
     let output = match pretty_args.output_format.as_str() {
         "ast-json" => serialize_model(&model),
+        "expression-domains" => serialize_domains(&model),
         // "add_new_flag" => method(),
         _ => {
             return Err(anyhow!(
-                "Unknown output format {}; supports [ast-json]",
+                "Unknown output format {}; supports [ast-json, expression-domains]",
                 &pretty_args.output_format
             ));
         }
diff --git a/crates/conjure-cp-cli/src/utils/testing.rs b/crates/conjure-cp-cli/src/utils/testing.rs
index bf09b9c759..352d394812 100644
--- a/crates/conjure-cp-cli/src/utils/testing.rs
+++ b/crates/conjure-cp-cli/src/utils/testing.rs
@@ -13,7 +13,7 @@ use std::io::{BufRead, BufReader, Write};
 use std::sync::{Arc, RwLock};
 use uniplate::Uniplate;
 
-use conjure_cp::ast::{AbstractLiteral, GroundDomain, Moo, SerdeModel};
+use conjure_cp::ast::{AbstractLiteral, ExprInfo, GroundDomain, Moo, SerdeModel};
 use conjure_cp::context::Context;
 use serde_json::{Error as JsonError, Value as JsonValue};
 
@@ -115,6 +115,11 @@ pub fn serialize_model(model: &ConjureModel) -> Result<String, JsonError> {
     serde_json::to_string_pretty(&sorted_json)
 }
 
+pub fn serialize_domains(model: &ConjureModel) -> Result<String, JsonError> {
+    let exprs: Vec<ExprInfo> = model.constraints().iter().map(ExprInfo::create).collect();
+    serde_json::to_string_pretty(&exprs)
+}
+
 pub fn save_model_json(
     model: &ConjureModel,
     path: &str,
diff --git a/crates/conjure-cp-core/src/ast/model.rs b/crates/conjure-cp-core/src/ast/model.rs
index 8c265d9534..95a73ec2ce 100644
--- a/crates/conjure-cp-core/src/ast/model.rs
+++ b/crates/conjure-cp-core/src/ast/model.rs
@@ -3,6 +3,7 @@ use std::fmt::{Debug, Display};
 use std::hash::Hash;
 use std::sync::{Arc, RwLock};
 
+use crate::ast::Domain;
 use crate::context::Context;
 use crate::{bug, into_matrix_expr};
 use derivative::Derivative;
@@ -549,3 +550,26 @@ impl SerdeModel {
         model.collect_stable_id_mapping()
     }
 }
+
+/// A struct for the information about expressions
+#[serde_as]
+#[derive(Serialize, Deserialize)]
+pub struct ExprInfo {
+    pretty: String,
+    domain: Option<Moo<Domain>>,
+    children: Vec<ExprInfo>,
+}
+
+impl ExprInfo {
+    pub fn create(expr: &Expression) -> ExprInfo {
+        let pretty = expr.to_string();
+        let domain = expr.domain_of();
+        let children = expr.children().iter().map(Self::create).collect();
+
+        ExprInfo {
+            pretty,
+            domain,
+            children,
+        }
+    }
+}
diff --git a/tests-integration/tests/domain_tightening/README.md b/tests-integration/tests/domain_tightening/README.md
new file mode 100644
index 0000000000..91b1e4eb7e
--- /dev/null
+++ b/tests-integration/tests/domain_tightening/README.md
@@ -0,0 +1,13 @@
+# Domain Tightening Tests
+These tests are designed to check whether or not the pruning stage reduces the domains of expressions without making them invalid.
+
+They will work by running the same underlying functions used in the `pretty <> --output-format=expression-domains` command.
+
+The general steps of the algorithm (TBC) will likely involve:
+1. Parse essence file
+2. Get the domains of the expressions
+
+We can then add subsequent steps that will run some ac-style algorithm and recheck the domains.
+
+## How to Run
+cargo test tests_domain_tightening
\ No newline at end of file
diff --git a/tests-integration/tests/domain_tightening_tests.rs b/tests-integration/tests/domain_tightening_tests.rs
new file mode 100644
index 0000000000..ed4200ad86
--- /dev/null
+++ b/tests-integration/tests/domain_tightening_tests.rs
@@ -0,0 +1,114 @@
+use std::{
+    env,
+    error::Error,
+    fs,
+    sync::{Arc, RwLock},
+};
+
+use conjure_cp::parse::tree_sitter::{parse_essence_file, parse_essence_file_native};
+use conjure_cp::settings::Parser;
+use conjure_cp::{
+    Model, ast::ExprInfo, context::Context, parse::tree_sitter::errors::ParseErrorCollection,
+};
+use tests_integration::TestConfig;
+
+/// Parser function used by expression domain tests.
+type ParseFn = fn(&str, Arc<RwLock<Context<'static>>>) -> Result<Model, Box<ParseErrorCollection>>;
+
+/// Runs a test for one model using each configured parser
+fn expression_domain_test(
+    path: &str,
+    filename: &str,
+    extension: &str,
+) -> Result<(), Box<dyn Error>> {
+    let accept = env::var("ACCEPT").unwrap_or("false".to_string()) == "true";
+
+    let file_config: TestConfig =
+        if let Ok(config_contents) = fs::read_to_string(format!("{path}/config.toml")) {
+            toml::from_str(&config_contents).unwrap()
+        } else {
+            Default::default()
+        };
+
+    if accept {
+        clean_test_dir_for_accept(path)?;
+    }
+
+    let parsers = file_config
+        .configured_parsers()
+        .map_err(|err| std::io::Error::new(std::io::ErrorKind::InvalidInput, err))?;
+
+    for parser in parsers {
+        let case_name = parser.to_string();
+        let parse = match parser {
+            Parser::TreeSitter => parse_essence_file_native,
+            Parser::ViaConjure => parse_essence_file,
+        };
+        expression_domain_test_inner(path, filename, &case_name, extension, parse)?;
+    }
+
+    Ok(())
+}
+
+fn expression_domain_test_inner(
+    path: &str,
+    input_filename: &str,
+    case_name: &str,
+    extension: &str,
+    parse: ParseFn,
+) -> Result<(), Box<dyn Error>> {
+    unimplemented!()
+}
+
+fn clean_test_dir_for_accept(path: &str) -> Result<(), std::io::Error> {
+    for entry in std::fs::read_dir(path)? {
+        let entry = entry?;
+        let file_name = entry.file_name();
+        let file_name = file_name.to_string_lossy();
+        let entry_path = entry.path();
+
+        if entry_path.is_dir() {
+            continue;
+        }
+
+        let keep = if file_name == "config.toml" {
+            true
+        } else {
+            let is_model_file = entry_path
+                .extension()
+                .and_then(|ext| ext.to_str())
+                .is_some_and(|ext| ext == "essence");
+            let is_generated_or_expected =
+                file_name.contains(".generated") || file_name.contains(".expected");
+            is_model_file && !is_generated_or_expected
+        };
+
+        if keep {
+            continue;
+        }
+
+        std::fs::remove_file(entry_path)?;
+    }
+
+    Ok(())
+}
+
+/// Returns the saved expression JSON path
+fn expression_domains_json_path(path: &str, case_name: &str, file_type: &str) -> String {
+    format!("{path}/{case_name}.{file_type}.serialised.json")
+}
+
+/// Reads and initialises a saved expression domains snapshot.
+fn read_expression_domains_json(
+    context: &Arc<RwLock<Context<'static>>>,
+    path: &str,
+    case_name: &str,
+    file_type: &str,
+) -> Result<Vec<ExprInfo>, std::io::Error> {
+    let serialised = fs::read_to_string(expression_domains_json_path(path, case_name, file_type))?;
+    let exprs: Vec<ExprInfo> = serde_json::from_str(&serialised).map_err(std::io::Error::other)?;
+
+    Ok(exprs)
+}
+
+// include!(concat!(env!("OUT_DIR"), "/gen_tests_domain_tightening.rs"));