diff --git a/Cargo.lock b/Cargo.lock
index 695b8aab..73b3bbcc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -39,6 +39,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "allocator-api2"
+version = "0.2.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c6cb57a04249c6480766f7f7cef5467412af1490f8d1e243141daddada3264f"
+
 [[package]]
 name = "android-tzdata"
 version = "0.1.1"
@@ -115,6 +121,51 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
 
+[[package]]
+name = "ascent"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "542b90d362e62ae00b8a9f1c8887919fe5cb4a07c64423b9ab72ab78f4b27f41"
+dependencies = [
+ "ascent_base",
+ "ascent_macro",
+ "boxcar",
+ "cfg-if",
+ "dashmap",
+ "hashbrown 0.14.5",
+ "instant",
+ "once_cell",
+ "paste",
+ "rayon",
+ "rustc-hash",
+]
+
+[[package]]
+name = "ascent_base"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "606412229e80de366935b461eaef5016a9725064151e52ea35f200e7541c2912"
+dependencies = [
+ "paste",
+]
+
+[[package]]
+name = "ascent_macro"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67685ce7f6568cfd9671322ed3d7c7322ff8ec6a81e07d5323f997e118885972"
+dependencies = [
+ "ascent_base",
+ "derive-syn-parse",
+ "duplicate",
+ "itertools 0.12.1",
+ "lazy_static",
+ "petgraph",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.82",
+]
+
 [[package]]
 name = "assert_fs"
 version = "1.1.2"
@@ -218,6 +269,12 @@ version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
 
+[[package]]
+name = "boxcar"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38c99613cb3cd7429889a08dfcf651721ca971c86afa30798461f8eee994de47"
+
 [[package]]
 name = "bstr"
 version = "1.10.0"
@@ -442,6 +499,7 @@ name = "crux_cli"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "ascent",
  "clap",
  "console",
  "guppy",
@@ -591,12 +649,37 @@ dependencies = [
  "syn 2.0.82",
 ]
 
+[[package]]
+name = "dashmap"
+version = "5.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
+dependencies = [
+ "cfg-if",
+ "hashbrown 0.14.5",
+ "lock_api",
+ "once_cell",
+ "parking_lot_core",
+ "rayon",
+]
+
 [[package]]
 name = "debug-ignore"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ffe7ed1d93f4553003e20b629abe9085e1e81b1429520f897f8f8860bc6dfc21"
 
+[[package]]
+name = "derive-syn-parse"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d65d7ce8132b7c0e54497a4d9a55a1c2a0912a0d786cf894472ba818fba45762"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.82",
+]
+
 [[package]]
 name = "derive_builder"
 version = "0.20.2"
@@ -648,6 +731,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "duplicate"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de78e66ac9061e030587b2a2e75cc88f22304913c907b11307bca737141230cb"
+
 [[package]]
 name = "either"
 version = "1.13.0"
@@ -950,7 +1039,7 @@ dependencies = [
  "fixedbitset",
  "guppy-workspace-hack",
  "indexmap",
- "itertools",
+ "itertools 0.13.0",
  "nested",
  "once_cell",
  "pathdiff",
@@ -969,6 +1058,17 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "92620684d99f750bae383ecb3be3748142d6095760afd5cbcf2261e9a279d780"
 
+[[package]]
+name = "hashbrown"
+version = "0.14.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
+dependencies = [
+ "ahash",
+ "allocator-api2",
+ "rayon",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.15.0"
@@ -1102,7 +1202,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "707907fe3c25f5424cce2cb7e1cbcafee6bdbe735ca90ef77c29e84591e5b9da"
 dependencies = [
  "equivalent",
- "hashbrown",
+ "hashbrown 0.15.0",
 ]
 
 [[package]]
@@ -1138,6 +1238,15 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "itertools"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba291022dbbd398a455acf126c1e341954079855bc60dfdda641363bd6922569"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itertools"
 version = "0.13.0"
@@ -1321,6 +1430,12 @@ dependencies = [
  "windows-targets",
 ]
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "pathdiff"
 version = "0.2.2"
@@ -1632,6 +1747,26 @@ dependencies = [
  "rand_core 0.5.1",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.7"
@@ -1664,6 +1799,12 @@ version = "0.1.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "719b953e2095829ee67db738b3bfa9fa368c94900df327b3f07fe6e794d2fe1f"
 
+[[package]]
+name = "rustc-hash"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
+
 [[package]]
 name = "rustdoc-json"
 version = "0.9.2"
diff --git a/crux_cli/Cargo.toml b/crux_cli/Cargo.toml
index c7f289ae..07e8a727 100644
--- a/crux_cli/Cargo.toml
+++ b/crux_cli/Cargo.toml
@@ -15,6 +15,7 @@ path = "src/main.rs"
 
 [dependencies]
 anyhow.workspace = true
+ascent = "0.7.0"
 clap = { version = "4.4.18", features = ["derive"] }
 console = "0.15.8"
 guppy = "0.17.4"
diff --git a/crux_cli/codegen.fish b/crux_cli/codegen.fish
index 4064d165..5ef3f181 100755
--- a/crux_cli/codegen.fish
+++ b/crux_cli/codegen.fish
@@ -3,9 +3,6 @@
 cargo build
 
 for d in ../examples/hello_world
-    echo ""
-    echo "---------------"
-    echo "Public API for $d"
     pushd $d
     ../../target/debug/crux codegen --lib shared
     popd
diff --git a/crux_cli/src/codegen/mod.rs b/crux_cli/src/codegen/mod.rs
index da7bd9c0..51a51679 100644
--- a/crux_cli/src/codegen/mod.rs
+++ b/crux_cli/src/codegen/mod.rs
@@ -17,10 +17,19 @@ pub async fn codegen(args: &CodegenArgs) -> Result<()> {
         bail!("Could not find workspace package with path {}", args.lib)
     };
 
-    let json_path = rustdoc_json::Builder::default()
-        .toolchain("nightly")
-        .manifest_path(lib.manifest_path())
-        .build()?;
+    // let json_path = rustdoc_json::Builder::default()
+    //     .toolchain("nightly")
+    //     .manifest_path(lib.manifest_path())
+    //     .build()?;
+    let json_path = lib
+        .manifest_path()
+        .parent()
+        .unwrap()
+        .parent()
+        .unwrap()
+        .join("target")
+        .join("doc")
+        .join("shared.json");
 
     let crate_: Crate = spawn_blocking(move || -> Result<Crate> {
         let file = File::open(json_path)?;
@@ -29,9 +38,7 @@ pub async fn codegen(args: &CodegenArgs) -> Result<()> {
     })
     .await??;
 
-    println!("Parsing rustdoc JSON, version {}", crate_.format_version);
-    let out = parser::parse(&crate_)?;
-    println!("{}", out);
+    parser::parse(&crate_)?;
 
     Ok(())
 }
diff --git a/crux_cli/src/codegen/parser.rs b/crux_cli/src/codegen/parser.rs
index aac68ece..817f6455 100644
--- a/crux_cli/src/codegen/parser.rs
+++ b/crux_cli/src/codegen/parser.rs
@@ -1,27 +1,59 @@
 use std::collections::HashMap;
 
 use anyhow::{anyhow, Result};
-use petgraph::{dot::Dot, graph::NodeIndex, Graph};
-use rustdoc_types::{Crate, Enum, Id, Impl, Item, ItemEnum, Type, VariantKind};
+use ascent::ascent;
+use rustdoc_types::{Crate, Enum, Id, Impl, Item, ItemEnum, ItemSummary, Path, Type, VariantKind};
+use serde::Serialize;
+
+ascent! {
+    relation edge(Node, Node, Edge);
+
+    relation for_type(Node, Node);
+    for_type(impl_, type_) <-- edge(impl_, type_, Edge::ForType);
+
+    relation of_trait(Node, Node);
+    of_trait(impl_, trait_) <-- edge(impl_, trait_, Edge::Trait);
+
+    relation implements(Node, Node);
+    implements(type_, trait_) <-- for_type(impl_, type_), of_trait(impl_, trait_);
+
+    relation struct_fields(Node, Node);
+    struct_fields(struct_, field) <-- edge(struct_, field, Edge::HasField);
+
+    relation enum_variants(Node, Node);
+    enum_variants(enum_, variant) <-- edge(enum_, variant, Edge::HasVariant);
+}
 
 pub fn parse(crate_: &Crate) -> Result<String> {
-    let mut graph = Graph::new();
-    let mut nodes = HashMap::new();
+    let mut prog = AscentProgram::default();
+    let mut nodes_by_id = HashMap::new();
 
-    // nodes
-    for (id, item) in crate_.index.clone() {
-        nodes.insert(id, graph.add_node(Node { id, item }));
+    // items
+    for (id, item) in &crate_.index {
+        nodes_by_id
+            .entry(*id)
+            .or_insert_with(|| Node::new(*id))
+            .item = Some(item.clone());
+    }
+
+    // paths
+    for (id, path) in &crate_.paths {
+        nodes_by_id
+            .entry(*id)
+            .or_insert_with(|| Node::new(*id))
+            .path = Some(path.clone());
     }
 
-    let node = |id| -> Result<&NodeIndex> {
-        nodes
+    let node_by_id = |id: &Id| -> Result<&Node> {
+        nodes_by_id
             .get(id)
             .ok_or_else(|| anyhow!("Could not find node with id {:?}", id))
     };
 
     // edges
     for (id, item) in &crate_.index {
-        let source = node(id)?;
+        let source = node_by_id(id)?.clone();
+
         match &item.inner {
             ItemEnum::Module(_module) => (),
             ItemEnum::ExternCrate { name: _, rename: _ } => (),
@@ -33,7 +65,11 @@ pub fn parse(crate_: &Crate) -> Result<String> {
                     rustdoc_types::StructKind::Tuple(fields) => {
                         for field in fields {
                             if let Some(id) = field {
-                                graph.add_edge(*source, *node(&id)?, Edge::HasField);
+                                prog.edge.push((
+                                    source.clone(),
+                                    node_by_id(&id)?.clone(),
+                                    Edge::HasField,
+                                ));
                             }
                         }
                     }
@@ -42,18 +78,20 @@ pub fn parse(crate_: &Crate) -> Result<String> {
                         has_stripped_fields: _,
                     } => {
                         for id in fields {
-                            graph.add_edge(*source, *node(&id)?, Edge::HasField);
+                            prog.edge.push((
+                                source.clone(),
+                                node_by_id(&id)?.clone(),
+                                Edge::HasField,
+                            ));
                         }
                     }
                 };
-                for id in &s.impls {
-                    graph.add_edge(*source, *node(&id)?, Edge::Implements);
-                }
             }
             ItemEnum::StructField(_) => (),
             ItemEnum::Enum(Enum { variants, .. }) => {
                 for id in variants {
-                    graph.add_edge(*source, *node(&id)?, Edge::HasVariant);
+                    prog.edge
+                        .push((source.clone(), node_by_id(&id)?.clone(), Edge::HasVariant));
                 }
             }
             ItemEnum::Variant(v) => {
@@ -65,7 +103,11 @@ pub fn parse(crate_: &Crate) -> Result<String> {
                         has_stripped_fields: _,
                     } => {
                         for field in fields {
-                            graph.add_edge(*source, *node(&field)?, Edge::HasField);
+                            prog.edge.push((
+                                source.clone(),
+                                node_by_id(&field)?.clone(),
+                                Edge::HasField,
+                            ));
                         }
                     }
                 };
@@ -74,13 +116,32 @@ pub fn parse(crate_: &Crate) -> Result<String> {
             ItemEnum::Trait(_) => (),
             ItemEnum::TraitAlias(_trait_alias) => (),
             ItemEnum::Impl(Impl {
+                trait_:
+                    Some(Path {
+                        id: trait_id,
+                        name,
+                        args: _,
+                    }),
                 for_: Type::ResolvedPath(target),
                 items,
                 ..
             }) => {
-                graph.add_edge(*source, *node(&target.id)?, Edge::ImplFor);
+                if !["App", "Effect"].contains(&name.as_str()) {
+                    continue;
+                }
+                prog.edge.push((
+                    source.clone(),
+                    node_by_id(&target.id)?.clone(),
+                    Edge::ForType,
+                ));
+                prog.edge
+                    .push((source.clone(), node_by_id(trait_id)?.clone(), Edge::Trait));
                 for id in items {
-                    graph.add_edge(*source, *node(&id)?, Edge::AssociatedItem);
+                    prog.edge.push((
+                        source.clone(),
+                        node_by_id(&id)?.clone(),
+                        Edge::AssociatedItem,
+                    ));
                 }
             }
             ItemEnum::Impl(_) => (),
@@ -100,29 +161,62 @@ pub fn parse(crate_: &Crate) -> Result<String> {
                 bounds: _,
                 type_: Some(Type::ResolvedPath(target)),
             } => {
-                if let Ok(dest) = node(&target.id) {
-                    graph.add_edge(*source, *dest, Edge::AssociatedType);
+                if let Ok(dest) = node_by_id(&target.id) {
+                    prog.edge
+                        .push((source.clone(), dest.clone(), Edge::AssociatedType));
                 }
             }
             ItemEnum::AssocType { .. } => (),
         }
     }
-    let out = Dot::new(&graph);
-    Ok(format!("{:?}", out))
+
+    prog.run();
+
+    std::fs::write(
+        "/tmp/implements.json",
+        serde_json::to_string(&prog.implements).unwrap(),
+    )?;
+    std::fs::write(
+        "/tmp/struct_fields.json",
+        serde_json::to_string(&prog.struct_fields).unwrap(),
+    )?;
+    std::fs::write(
+        "/tmp/enum_variants.json",
+        serde_json::to_string(&prog.enum_variants).unwrap(),
+    )?;
+
+    Ok(format!(""))
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
 struct Node {
     id: Id,
-    item: Item,
+    item: Option<Item>,
+    path: Option<ItemSummary>,
+}
+
+impl Node {
+    fn new(id: Id) -> Self {
+        Self {
+            id,
+            item: None,
+            path: None,
+        }
+    }
+}
+
+impl std::hash::Hash for Node {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.id.hash(state);
+    }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 enum Edge {
-    ImplFor,
-    HasField,
-    Implements,
     AssociatedItem,
     AssociatedType,
+    ForType,
+    HasField,
     HasVariant,
+    Trait,
 }