diff --git a/.github/workflows/actions.lock b/.github/workflows/actions.lock
index 34819c5..aff8754 100644
--- a/.github/workflows/actions.lock
+++ b/.github/workflows/actions.lock
@@ -3,14 +3,6 @@
 # Docs: https://gh.io/actions-lockfile
 version: 'v0.0.2'
 workflows:
-    '.github/workflows/governance.yml': []
-    '.github/workflows/hypatia-scan.yml': []
-    '.github/workflows/label-triage.yml': []
-    '.github/workflows/labels.yml': []
-    '.github/workflows/mirror.yml': []
-    '.github/workflows/rust-ci.yml': []
-    '.github/workflows/scorecard.yml': []
-    '.github/workflows/secret-scanner.yml': []
     '.github/workflows/boj-build.yml':
         - 'actions/checkout@v4.1.7'
     '.github/workflows/cargo-audit.yml':
@@ -33,14 +25,19 @@ workflows:
         - 'dependabot/fetch-metadata@v2.2.0'
     '.github/workflows/dogfood-gate.yml':
         - 'actions/checkout@v4.3.1'
-        - 'hyperpolymath/a2ml-ecosystem@main'
+        - 'hyperpolymath/deed-ecosystem@main'
         - 'hyperpolymath/k9-ecosystem@main'
     '.github/workflows/generator-generic-ossf-slsa3-publish.yml':
         - 'actions/checkout@v6.0.1'
     '.github/workflows/ghcr-publish.yml':
         - 'actions/checkout@v6.0.1'
+    '.github/workflows/governance.yml': []
+    '.github/workflows/hypatia-scan.yml': []
     '.github/workflows/instant-sync.yml':
         - 'peter-evans/repository-dispatch@v3.0.0'
+    '.github/workflows/label-triage.yml': []
+    '.github/workflows/labels.yml': []
+    '.github/workflows/mirror.yml': []
     '.github/workflows/pages.yml':
         - 'actions/checkout@v4.4.0'
         - 'actions/deploy-pages@v4.0.5'
@@ -88,6 +85,9 @@ workflows:
         - 'dtolnay/rust-toolchain@v1'
         - 'goto-bus-stop/setup-zig@v2.2.1'
         - 'softprops/action-gh-release@v2.2.1'
+    '.github/workflows/rust-ci.yml': []
+    '.github/workflows/scorecard.yml': []
+    '.github/workflows/secret-scanner.yml': []
     '.github/workflows/stress-test.yml':
         - 'actions/checkout@v6.0.1'
         - 'dtolnay/rust-toolchain@v1'
@@ -251,14 +251,14 @@ dependencies:
         commit: 'sha1-ec49483bfc012387b227434aba94f59a6ecd0900'
         owner_id: 75048950
         repo_id: 623796603
-    'hyperpolymath/a2ml-ecosystem@main':
+    'hyperpolymath/deed-ecosystem@main':
         ref: 'main'
-        commit: 'sha1-c572785aab3898d9955f9e0370439631265802c9'
+        commit: 'sha1-f7a40a4d5cc82b2e73f861119baa6818d77a448d'
         owner_id: 6759885
         repo_id: 1275649586
     'hyperpolymath/k9-ecosystem@main':
         ref: 'main'
-        commit: 'sha1-921f599d0b5bc6de4627338b014059ab6bcea5b8'
+        commit: 'sha1-2155aa26a21758f2ba119f61bc7e0e1981c106fb'
         owner_id: 6759885
         repo_id: 1275650185
     'ksxgithub/github-actions-deploy-aur@v3.0.1':
diff --git a/.github/workflows/dogfood-gate.yml b/.github/workflows/dogfood-gate.yml
index 82864e2..86b0165 100644
--- a/.github/workflows/dogfood-gate.yml
+++ b/.github/workflows/dogfood-gate.yml
@@ -41,7 +41,7 @@ jobs:
 
       - name: Validate A2ML manifests
         if: steps.detect.outputs.count > 0
-        uses: hyperpolymath/a2ml-ecosystem/validate-action@main
+        uses: hyperpolymath/deed-ecosystem/validate-action@main
         with:
           path: '.'
           strict: 'false'
diff --git a/benches/bunsenite_bench.rs b/benches/bunsenite_bench.rs
index 0e836b5..183a345 100644
--- a/benches/bunsenite_bench.rs
+++ b/benches/bunsenite_bench.rs
@@ -7,7 +7,8 @@
 //! creation overhead and the `validate`-only fast path.
 
 use bunsenite::NickelLoader;
-use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use std::hint::black_box;
 
 // ---------------------------------------------------------------------------
 // Payload corpus
@@ -97,11 +98,9 @@ fn bench_throughput_parse(c: &mut Criterion) {
         ("large", LARGE_PAYLOAD),
     ] {
         group.throughput(Throughput::Bytes(payload.len() as u64));
-        group.bench_with_input(
-            BenchmarkId::new(label, payload.len()),
-            payload,
-            |b, src| b.iter(|| loader.parse_string(black_box(src), "bench.ncl")),
-        );
+        group.bench_with_input(BenchmarkId::new(label, payload.len()), payload, |b, src| {
+            b.iter(|| loader.parse_string(black_box(src), "bench.ncl"))
+        });
     }
 
     group.finish();
@@ -124,11 +123,9 @@ fn bench_throughput_validate(c: &mut Criterion) {
         ("large", LARGE_PAYLOAD),
     ] {
         group.throughput(Throughput::Bytes(payload.len() as u64));
-        group.bench_with_input(
-            BenchmarkId::new(label, payload.len()),
-            payload,
-            |b, src| b.iter(|| loader.validate(black_box(src), "bench.ncl")),
-        );
+        group.bench_with_input(BenchmarkId::new(label, payload.len()), payload, |b, src| {
+            b.iter(|| loader.validate(black_box(src), "bench.ncl"))
+        });
     }
 
     group.finish();
diff --git a/benches/parser.rs b/benches/parser.rs
index 529a0e4..1cb51a1 100644
--- a/benches/parser.rs
+++ b/benches/parser.rs
@@ -5,7 +5,8 @@
 //! Run with: cargo bench
 
 use bunsenite::NickelLoader;
-use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use std::hint::black_box;
 
 /// Simple configuration (~100 bytes)
 const SIMPLE_CONFIG: &str = r#"
diff --git a/src/loader.rs b/src/loader.rs
index 0e351b9..a962fcf 100644
--- a/src/loader.rs
+++ b/src/loader.rs
@@ -3,7 +3,7 @@
 //! Nickel file loader and parser
 //!
 //! This module provides the core functionality for loading and parsing Nickel
-//! configuration files using nickel-lang-core 0.9.1.
+//! configuration files using nickel-lang-core 0.18.0.
 //!
 //! # Core Responsibilities
 //!
@@ -12,18 +12,17 @@
 //! 3. **Evaluation**: Executing the Nickel program to produce a final configuration.
 //! 4. **Export**: Converting the evaluated configuration into standard formats (JSON).
 //!
-//! # API Compatibility Notes (nickel-lang-core 0.9.1)
+//! # API Compatibility Notes (nickel-lang-core 0.18.0)
 //!
-//! - `Program::new_from_source()` requires trace parameter: `std::io::sink()`
-//! - `eval_full()` takes no arguments (changed in 0.9.1)
-//! - Manual error conversion required via `serde_json::to_value()`
-//! - NO `into_diagnostics()` method available (deprecated)
+//! - In-memory sources are loaded through `ProgramBuilder`.
+//! - `eval_full()` takes no arguments.
+//! - Evaluated values are converted with `serde_json::to_value()`.
 
 use crate::error::{Error, Result};
 use nickel_lang_core::eval::cache::lazy::CBNCache;
-use nickel_lang_core::program::Program;
+use nickel_lang_core::program::{Program, ProgramBuilder};
+use nickel_lang_core::typecheck::TypecheckMode;
 use serde_json::Value;
-use std::io::Cursor;
 use std::path::Path;
 
 /// Type alias for the standard Program with CBN (Call-By-Need) caching.
@@ -88,27 +87,18 @@ impl NickelLoader {
     /// assert!(result.is_ok());
     /// ```
     pub fn parse_string(&self, source: &str, name: &str) -> Result<Value> {
-        // Create a Program from source
-        // API in 0.9.1: Program<CBNCache>::new_from_source(impl Read, impl Into<SourceName>, impl Write)
-        let mut program: NickelProgram = Program::new_from_source(
-            Cursor::new(source.as_bytes()),
-            name,
-            std::io::sink(), // Trace output (discarded)
-        )
-        .map_err(|e| {
-            let msg = format!("{:?}", e);
-            Error::parse_error(name, msg)
-        })?;
+        let mut program: NickelProgram = ProgramBuilder::new()
+            .add_source_string(source, name)
+            .build()
+            .map_err(|e| Error::parse_error(name, format!("{:?}", e)))?;
 
         // Evaluate the program
-        // API change in 0.9.1: eval_full takes no arguments
         let eval_result = program.eval_full().map_err(|e| {
             let msg = format!("{:?}", e);
             Error::evaluation_error(name, msg)
         })?;
 
         // Convert to JSON
-        // API change in 0.9.1: Manual conversion required, no into_diagnostics()
         let json_value = serde_json::to_value(&eval_result)
             .map_err(|e| Error::serialization_error(format!("Failed to convert to JSON: {}", e)))?;
 
@@ -171,13 +161,14 @@ impl NickelLoader {
     /// assert!(loader.validate("{ foo = }", "bad.ncl").is_err());
     /// ```
     pub fn validate(&self, source: &str, name: &str) -> Result<()> {
-        // Just try to create a Program - this performs parsing and type-checking
-        let _program: NickelProgram =
-            Program::new_from_source(Cursor::new(source.as_bytes()), name, std::io::sink())
-                .map_err(|e| {
-                    let msg = format!("{:?}", e);
-                    Error::parse_error(name, msg)
-                })?;
+        let mut program: NickelProgram = ProgramBuilder::new()
+            .add_source_string(source, name)
+            .build()
+            .map_err(|e| Error::parse_error(name, format!("{:?}", e)))?;
+
+        program
+            .typecheck(TypecheckMode::Walk)
+            .map_err(|e| Error::parse_error(name, format!("{:?}", e)))?;
 
         Ok(())
     }
diff --git a/tests/aspect_test.rs b/tests/aspect_test.rs
index b2a0208..bd8328f 100644
--- a/tests/aspect_test.rs
+++ b/tests/aspect_test.rs
@@ -104,9 +104,7 @@ fn aspect_moderately_deep_nesting_no_panic() {
 /// important guarantee is no crash.
 #[test]
 fn aspect_large_flat_record_no_panic() {
-    let fields: String = (0..1000)
-        .map(|i| format!("  field_{i} = {i},\n"))
-        .collect();
+    let fields: String = (0..1000).map(|i| format!("  field_{i} = {i},\n")).collect();
     let source = format!("{{\n{fields}}}");
     let result = loader().parse_string(&source, "large.ncl");
     // Must not panic.  Nickel may or may not handle 1000 fields; we only
@@ -202,7 +200,11 @@ fn aspect_internal_error_not_recoverable() {
 fn aspect_error_message_accessor_round_trips() {
     let msg = "custom diagnostic text";
     let err = Error::parse_error("test.ncl", msg);
-    assert_eq!(err.message(), msg, "message() should return the original message verbatim");
+    assert_eq!(
+        err.message(),
+        msg,
+        "message() should return the original message verbatim"
+    );
 }
 
 /// A `SerializationError` must be non-recoverable (it indicates an internal
diff --git a/tests/e2e_test.rs b/tests/e2e_test.rs
index 2fde617..d7f165f 100644
--- a/tests/e2e_test.rs
+++ b/tests/e2e_test.rs
@@ -134,7 +134,9 @@ fn e2e_array_round_trip() {
     assert_eq!(tags[1], "nickel");
     assert_eq!(tags[2], "config");
 
-    let counts = json["counts"].as_array().expect("counts should be an array");
+    let counts = json["counts"]
+        .as_array()
+        .expect("counts should be an array");
     assert_eq!(counts.len(), 3);
 }
 
@@ -249,8 +251,7 @@ fn e2e_validate_then_parse_consistent() {
 #[test]
 fn e2e_key_count_matches_source() {
     // Source has exactly 5 top-level fields.
-    let source =
-        r#"{ a = 1, b = 2, c = 3, d = 4, e = 5 }"#;
+    let source = r#"{ a = 1, b = 2, c = 3, d = 4, e = 5 }"#;
     let json = loader()
         .parse_string(source, "keycount.ncl")
         .expect("E2E: key-count config must parse");
diff --git a/tests/integration_test.rs b/tests/integration_test.rs
index 1075402..284a325 100644
--- a/tests/integration_test.rs
+++ b/tests/integration_test.rs
@@ -6,7 +6,7 @@
 //! that configuration parsing, error handling, and metadata constants
 //! behave correctly from an external consumer's perspective.
 
-use bunsenite::{NickelLoader, Error, NAME, RSR_TIER, TPCF_PERIMETER, VERSION};
+use bunsenite::{Error, NickelLoader, NAME, RSR_TIER, TPCF_PERIMETER, VERSION};
 
 /// Verify that NickelLoader can be constructed with default settings.
 #[test]
@@ -31,7 +31,11 @@ fn test_parse_simple_record() {
     let loader = NickelLoader::new();
     let input = r#"{ name = "bunsenite", version = "1.0.0" }"#;
     let result = loader.parse_string(input, "simple.ncl");
-    assert!(result.is_ok(), "Simple record should parse: {:?}", result.err());
+    assert!(
+        result.is_ok(),
+        "Simple record should parse: {:?}",
+        result.err()
+    );
     let json = result.unwrap();
     assert!(json.to_string().contains("bunsenite"));
     assert!(json.to_string().contains("1.0.0"));
@@ -43,7 +47,11 @@ fn test_parse_numeric_values() {
     let loader = NickelLoader::new();
     let input = r#"{ port = 8080, retries = 3 }"#;
     let result = loader.parse_string(input, "numeric.ncl");
-    assert!(result.is_ok(), "Numeric record should parse: {:?}", result.err());
+    assert!(
+        result.is_ok(),
+        "Numeric record should parse: {:?}",
+        result.err()
+    );
     let json = result.unwrap();
     let text = json.to_string();
     assert!(text.contains("8080"), "Should contain port value");
@@ -56,7 +64,11 @@ fn test_parse_boolean_values() {
     let loader = NickelLoader::new();
     let input = r#"{ enabled = true, debug = false }"#;
     let result = loader.parse_string(input, "bool.ncl");
-    assert!(result.is_ok(), "Boolean record should parse: {:?}", result.err());
+    assert!(
+        result.is_ok(),
+        "Boolean record should parse: {:?}",
+        result.err()
+    );
 }
 
 /// Verify that empty records parse without error.
@@ -65,7 +77,11 @@ fn test_parse_empty_record() {
     let loader = NickelLoader::new();
     let input = "{}";
     let result = loader.parse_string(input, "empty.ncl");
-    assert!(result.is_ok(), "Empty record should parse: {:?}", result.err());
+    assert!(
+        result.is_ok(),
+        "Empty record should parse: {:?}",
+        result.err()
+    );
 }
 
 /// Verify that invalid Nickel syntax produces an error, not a panic.
@@ -84,7 +100,10 @@ fn test_error_recoverability() {
     assert!(parse_err.is_recoverable(), "Parse errors are recoverable");
 
     let internal_err = Error::internal("unexpected state");
-    assert!(!internal_err.is_recoverable(), "Internal errors are not recoverable");
+    assert!(
+        !internal_err.is_recoverable(),
+        "Internal errors are not recoverable"
+    );
 }
 
 /// Verify crate metadata constants are correctly populated.
diff --git a/tests/property_test.rs b/tests/property_test.rs
index c1dfd73..4fc99f6 100644
--- a/tests/property_test.rs
+++ b/tests/property_test.rs
@@ -34,21 +34,18 @@ const CORPUS: &[(&str, &str)] = &[
     // 0 — single string field
     ("single_string", r#"{ greeting = "hello" }"#),
     // 1 — three scalar types
-    ("multi_scalar", r#"{ name = "cfg", count = 42, active = true }"#),
-    // 2 — nested record (one level)
     (
-        "nested_one",
-        r#"{ outer = { inner = "value", num = 7 } }"#,
+        "multi_scalar",
+        r#"{ name = "cfg", count = 42, active = true }"#,
     ),
+    // 2 — nested record (one level)
+    ("nested_one", r#"{ outer = { inner = "value", num = 7 } }"#),
     // 3 — array of strings
     ("array_strings", r#"{ tags = ["a", "b", "c", "d"] }"#),
     // 4 — array of integers
     ("array_ints", r#"{ nums = [10, 20, 30] }"#),
     // 5 — three-level nesting
-    (
-        "deep_nest",
-        r#"{ l1 = { l2 = { l3 = "leaf" } } }"#,
-    ),
+    ("deep_nest", r#"{ l1 = { l2 = { l3 = "leaf" } } }"#),
     // 6 — computed arithmetic
     ("computed", r#"{ x = 3 * 4, y = 100 - 1 }"#),
     // 7 — string concatenation
@@ -279,8 +276,5 @@ fn property_deep_nesting_preserved() {
 
     assert!(json["l1"].is_object(), "l1 should be an object");
     assert!(json["l1"]["l2"].is_object(), "l1.l2 should be an object");
-    assert_eq!(
-        json["l1"]["l2"]["l3"], "leaf",
-        "l1.l2.l3 should be 'leaf'"
-    );
+    assert_eq!(json["l1"]["l2"]["l3"], "leaf", "l1.l2.l3 should be 'leaf'");
 }