diff --git a/Cargo.lock b/Cargo.lock
index 9334ca674..acefd5505 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,6 +17,19 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "ahash"
+version = "0.8.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e89da841a80418a9b391ebaea17f5c112ffaaa96f621d2c285b5174da76b9011"
+dependencies = [
+ "cfg-if",
+ "getrandom 0.2.12",
+ "once_cell",
+ "version_check",
+ "zerocopy",
+]
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.2"
@@ -246,6 +259,38 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2bd12c1caf447e69cd4528f47f94d203fd2582878ecb9e9465484c4148a8223"
 
+[[package]]
+name = "camino"
+version = "1.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c59e92b5a388f549b863a7bea62612c09f24c8393560709a54558a9abdfb3b9c"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo-platform"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "694c8807f2ae16faecc43dc17d74b3eb042482789fd0eb64b39a2e04e087053f"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "cargo_metadata"
+version = "0.18.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d886547e41f740c616ae73108f6eb70afe6d940c7bc697cb30f13daec073037"
+dependencies = [
+ "camino",
+ "cargo-platform",
+ "semver",
+ "serde",
+ "serde_json",
+ "thiserror",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.83"
@@ -255,6 +300,16 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "cfg-expr"
+version = "0.15.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa50868b64a9a6fda9d593ce778849ea8715cd2a3d2cc17ffdb4a2f2f2f1961d"
+dependencies = [
+ "smallvec",
+ "target-lexicon",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -397,10 +452,13 @@ dependencies = [
  "anyhow",
  "clap",
  "console",
+ "guppy",
  "ignore",
  "libc",
  "ramhorns",
+ "rustdoc-types",
  "serde",
+ "serde_json",
  "similar",
  "tokio",
  "tokio-fd",
@@ -570,6 +628,12 @@ dependencies = [
  "syn 2.0.48",
 ]
 
+[[package]]
+name = "debug-ignore"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffe7ed1d93f4553003e20b629abe9085e1e81b1429520f897f8f8860bc6dfc21"
+
 [[package]]
 name = "derive_builder"
 version = "0.13.0"
@@ -634,6 +698,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "either"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11157ac094ffbdde99aa67b23417ebdd801842852b500e395a45a9c0aac03e4a"
+
 [[package]]
 name = "encode_unicode"
 version = "0.3.6"
@@ -707,6 +777,12 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "25cbce373ec4653f1a01a31e8a5e5ec0c622dc27ff9c4e6606eefef5cbbed4a5"
 
+[[package]]
+name = "fixedbitset"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -903,6 +979,39 @@ dependencies = [
  "walkdir",
 ]
 
+[[package]]
+name = "guppy"
+version = "0.17.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34e99a7734579b834a076ef11789783c153c6eb5fb3520ed15bc41f483f0f317"
+dependencies = [
+ "ahash",
+ "camino",
+ "cargo_metadata",
+ "cfg-if",
+ "debug-ignore",
+ "fixedbitset",
+ "guppy-workspace-hack",
+ "indexmap",
+ "itertools",
+ "nested",
+ "once_cell",
+ "pathdiff",
+ "petgraph",
+ "semver",
+ "serde",
+ "serde_json",
+ "smallvec",
+ "static_assertions",
+ "target-spec",
+]
+
+[[package]]
+name = "guppy-workspace-hack"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92620684d99f750bae383ecb3be3748142d6095760afd5cbcf2261e9a279d780"
+
 [[package]]
 name = "hashbrown"
 version = "0.14.3"
@@ -1067,6 +1176,15 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba291022dbbd398a455acf126c1e341954079855bc60dfdda641363bd6922569"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.10"
@@ -1171,6 +1289,12 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "nested"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca2b420f638f07fe83056b55ea190bb815f609ec5a35e7017884a10f78839c9e"
+
 [[package]]
 name = "num-traits"
 version = "0.2.17"
@@ -1234,12 +1358,31 @@ dependencies = [
  "windows-targets 0.48.5",
 ]
 
+[[package]]
+name = "pathdiff"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8835116a5c179084a830efb3adc117ab007512b535bc1a21c991d3b32a6b44dd"
+dependencies = [
+ "camino",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3148f5046208a5d56bcfc03053e3ca6334e51da8dfb19b6cdc8b306fae3283e"
 
+[[package]]
+name = "petgraph"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1d3afd2628e69da2be385eb6f2fd57c8ac7977ceeff6dc166ff1657b0e386a9"
+dependencies = [
+ "fixedbitset",
+ "indexmap",
+]
+
 [[package]]
 name = "phf"
 version = "0.10.1"
@@ -1563,6 +1706,15 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "rustdoc-types"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0904b9147011800e63763fb9e49bbeaf76c1b6ab8982824c659dce5433712559"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "rustix"
 version = "0.38.31"
@@ -1602,6 +1754,9 @@ name = "semver"
 version = "1.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b97ed7a9823b74f99c7742f5336af7be5ecd3eeafcb1507d1fa93347b1d589b0"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "serde"
@@ -1650,9 +1805,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.113"
+version = "1.0.114"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "69801b70b1c3dac963ecb03a364ba0ceda9cf60c71cfe475e99864759c8b8a79"
+checksum = "c5f09b1bd632ef549eaa9f60a1f8de742bdbc698e6cee2095fc84dde5f549ae0"
 dependencies = [
  "itoa",
  "ryu",
@@ -1777,6 +1932,24 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "target-lexicon"
+version = "0.12.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1fc403891a21bcfb7c37834ba66a547a8f402146eba7265b5a6d88059c9ff2f"
+
+[[package]]
+name = "target-spec"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36a8e795b1824524d13cdf04f73cf8b4f244ce86c96b4d2a83a6ca1a753d2752"
+dependencies = [
+ "cfg-expr",
+ "guppy-workspace-hack",
+ "target-lexicon",
+ "unicode-ident",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.9.0"
@@ -2263,3 +2436,23 @@ checksum = "56c1936c4cc7a1c9ab21a1ebb602eb942ba868cbd44a99cb7cdc5892335e1c85"
 dependencies = [
  "linked-hash-map",
 ]
+
+[[package]]
+name = "zerocopy"
+version = "0.7.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "74d4d3961e53fa4c9a25a8637fc2bfaf2595b3d3ae34875568a5cf64787716be"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.7.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ce1b18ccd8e73a9321186f97e46f9f04b778851177567b1975109d26a08d2a6"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.48",
+]
diff --git a/crux_cli/Cargo.toml b/crux_cli/Cargo.toml
index be9103ad1..9955b3a80 100644
--- a/crux_cli/Cargo.toml
+++ b/crux_cli/Cargo.toml
@@ -17,10 +17,13 @@ path = "src/main.rs"
 anyhow.workspace = true
 clap = { version = "4.3.24", features = ["derive"] }
 console = "0.15.8"
+guppy = "0.17.5"
 ignore = "0.4.22"
 libc = "0.2.153"
 ramhorns = "0.14.0"
+rustdoc-types = "0.24.0"
 serde = { workspace = true, features = ["derive"] }
+serde_json = "1.0.114"
 similar = { version = "2.4.0", features = ["inline"] }
 tokio = { version = "1.36.0", features = ["full"] }
 tokio-fd = "0.3.0"
diff --git a/crux_cli/src/args.rs b/crux_cli/src/args.rs
index f94e283ad..70aabd562 100644
--- a/crux_cli/src/args.rs
+++ b/crux_cli/src/args.rs
@@ -48,9 +48,9 @@ pub(crate) struct DoctorArgs {
 
 #[derive(Args)]
 pub(crate) struct CodegenArgs {
-    /// path to the directory containing the Cargo.toml manifest
+    /// name of the library containing your Crux App
     #[arg(long, short)]
-    pub path: PathBuf,
+    pub lib: String,
 }
 
 #[cfg(test)]
diff --git a/crux_cli/src/codegen.rs b/crux_cli/src/codegen.rs
index efc89a60d..3b9316e13 100644
--- a/crux_cli/src/codegen.rs
+++ b/crux_cli/src/codegen.rs
@@ -1,10 +1,20 @@
-use anyhow::Result;
-use std::io::{stdout, IsTerminal};
-use tokio::process::Command;
+use anyhow::{bail, Result};
+use rustdoc_types::{Crate, Impl, ItemEnum, Path};
+use std::{
+    fs::File,
+    io::{stdout, IsTerminal},
+};
+use tokio::{process::Command, task::spawn_blocking};
 
-use crate::{args::CodegenArgs, command_runner};
+use crate::{args::CodegenArgs, command_runner, graph};
 
 pub async fn codegen(args: &CodegenArgs) -> Result<()> {
+    let graph = graph::compute_package_graph()?;
+
+    let Ok(lib) = graph.workspace().member_by_path(&args.lib) else {
+        bail!("Could not find workspace package with path {}", args.lib)
+    };
+
     let mut cmd = Command::new("cargo");
     cmd.env("RUSTC_BOOTSTRAP", "1")
         .env(
@@ -12,8 +22,9 @@ pub async fn codegen(args: &CodegenArgs) -> Result<()> {
             "-Z unstable-options --output-format=json --cap-lints=allow",
         )
         .arg("doc")
+        .arg("--no-deps")
         .arg("--manifest-path")
-        .arg(&args.path)
+        .arg(lib.manifest_path())
         .arg("--lib");
     if stdout().is_terminal() {
         cmd.arg("--color=always");
@@ -21,5 +32,37 @@ pub async fn codegen(args: &CodegenArgs) -> Result<()> {
 
     command_runner::run(&mut cmd).await?;
 
+    let target_directory = graph.workspace().target_directory().as_std_path();
+    let json_path = target_directory
+        .join("doc")
+        .join(format!("{}.json", lib.name().replace("-", "_")));
+
+    let rustdoc: Crate = spawn_blocking(move || {
+        let file = File::open(&json_path)?;
+        let crate_: Crate = serde_json::from_reader(file)?;
+        Ok::<rustdoc_types::Crate, anyhow::Error>(crate_)
+    })
+    .await??;
+
+    if let Some(name) = rustdoc.index.iter().find_map(|(_k, v)| {
+        if let ItemEnum::Impl(Impl {
+            trait_: Some(rustdoc_types::Path {
+                name: trait_name, ..
+            }),
+            for_: rustdoc_types::Type::ResolvedPath(Path { name, .. }),
+            ..
+        }) = &v.inner
+        {
+            (trait_name == &"App".to_string()).then(|| name)
+        } else {
+            None
+        }
+    }) {
+        println!(
+            "The struct that implements crux_core::App is called {:?}",
+            name
+        );
+    }
+
     Ok(())
 }
diff --git a/crux_cli/src/graph.rs b/crux_cli/src/graph.rs
new file mode 100644
index 000000000..90cc84ec0
--- /dev/null
+++ b/crux_cli/src/graph.rs
@@ -0,0 +1,8 @@
+use anyhow::{anyhow, Result};
+use guppy::{graph::PackageGraph, MetadataCommand};
+
+pub(crate) fn compute_package_graph() -> Result<PackageGraph> {
+    let mut cmd = MetadataCommand::new();
+    let package_graph = PackageGraph::from_command(&mut cmd);
+    package_graph.map_err(|e| anyhow!(e))
+}
diff --git a/crux_cli/src/main.rs b/crux_cli/src/main.rs
index 2443c6ab0..453962559 100644
--- a/crux_cli/src/main.rs
+++ b/crux_cli/src/main.rs
@@ -10,6 +10,7 @@ mod command_runner;
 mod config;
 mod diff;
 mod doctor;
+mod graph;
 mod template;
 mod workspace;