diff --git a/AGENTS.md b/AGENTS.md
index d6292c9..d843ef9 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -5,7 +5,9 @@
 ## 1. Build & Test
 
 ```bash
-# Full build + tests
+# Tests
+nix flake check
+# Full build
 nix build .#
 ```
 
diff --git a/docs/arborix-bundle-cbor-v1.md b/docs/arborix-bundle-cbor-v1.md
new file mode 100644
index 0000000..b9f9441
--- /dev/null
+++ b/docs/arborix-bundle-cbor-v1.md
@@ -0,0 +1,339 @@
+# Arborix Portable Bundle v1 (CBOR Manifest Profile)
+
+Status: **Draft, implementation-aligned** (derived from `src/Wire.hs` as of 2026-05-07)
+
+This document specifies the **actual on-wire format and validation behavior** currently implemented by `tricu` for Arborix bundles, with a focus on the newer CBOR manifest path.
+
+---
+
+## 1. Scope
+
+This profile defines:
+
+1. The binary container envelope (header + section directory + section payloads).
+2. The CBOR manifest section format.
+3. The Merkle node section format.
+4. Decode/verify/import behavior in `Wire.hs`.
+5. Known gaps and sane resolutions.
+
+Non-goals:
+
+- tricu source parsing/lambda elimination/module semantics.
+- Signature systems / trust policy.
+- Compression codecs beyond `none`.
+
+---
+
+## 2. Container format
+
+A bundle is a byte stream:
+
+```
+[32-byte header]
+[section directory: section_count * 60 bytes]
+[section payload bytes...]
+```
+
+### 2.1 Header (32 bytes)
+
+| Field | Size | Encoding | Value / Notes |
+|---|---:|---|---|
+| Magic | 8 | raw bytes | `41 52 42 4f 52 49 58 00` (`"ARBORIX\0"`) |
+| Major | 2 | u16 BE | Must be `1` |
+| Minor | 2 | u16 BE | Currently `0` |
+| SectionCount | 4 | u32 BE | Number of section directory entries |
+| Flags | 8 | u64 BE | Currently emitted as `0`; not interpreted |
+| DirectoryOffset | 8 | u64 BE | Offset of section directory (currently `32`) |
+
+Reader behavior:
+- Reject if total bytes < 32.
+- Reject bad magic.
+- Reject major != 1.
+
+### 2.2 Section directory entry (60 bytes each)
+
+| Field | Size | Encoding | Notes |
+|---|---:|---|---|
+| Type | 4 | u32 BE | e.g. 1=manifest, 2=nodes |
+| Version | 2 | u16 BE | Currently emitted as `1`; not enforced on read |
+| Flags | 2 | u16 BE | bit0 = critical |
+| Compression | 2 | u16 BE | `0` = none (required) |
+| DigestAlgorithm | 2 | u16 BE | `1` = SHA-256 (required) |
+| Offset | 8 | u64 BE | Absolute byte offset |
+| Length | 8 | u64 BE | Section payload length |
+| Digest | 32 | raw bytes | SHA-256 of section bytes |
+
+Reader behavior:
+- Reject unknown **critical** section types.
+- Reject compression != 0.
+- Reject digest algorithm != 1.
+- Reject out-of-bounds sections.
+- Reject digest mismatch.
+
+### 2.3 Required section types
+
+| Type | Name | Required |
+|---:|---|---|
+| 1 | manifest | yes |
+| 2 | nodes | yes |
+
+Decode currently rejects duplicate section type 1 or 2.
+
+---
+
+## 3. Manifest section (CBOR)
+
+Manifest bytes are CBOR-encoded map data (using `cborg`).
+
+### 3.1 Top-level manifest schema
+
+Top-level map has **exactly 8 keys** in this exact decode order in current implementation:
+
+1. `schema` (text)
+2. `bundleType` (text)
+3. `tree` (map)
+4. `runtime` (map)
+5. `closure` (text: `"complete"|"partial"`)
+6. `roots` (array)
+7. `exports` (array)
+8. `metadata` (map)
+
+> Important: Current decoder is order-strict; it expects keys in this sequence.
+
+### 3.2 Nested structures
+
+#### `tree` map (3 keys, order-strict)
+- `calculus`: text
+- `nodeHash`: map
+- `nodePayload`: text
+
+`nodeHash` map (2 keys, order-strict):
+- `algorithm`: text
+- `domain`: text
+
+#### `runtime` map (4 keys, order-strict)
+- `semantics`: text
+- `evaluation`: text
+- `abi`: text
+- `capabilities`: array(text)
+
+#### `roots` array of maps
+Each root map has 2 keys (order-strict):
+- `hash`: bytes (raw 32-byte hash payload encoded as CBOR byte string)
+- `role`: text
+
+#### `exports` array of maps
+Each export map has 4 keys (order-strict):
+- `name`: text
+- `root`: bytes (32-byte hash)
+- `kind`: text
+- `abi`: text
+
+#### `metadata` map
+Flexible key set; decoded as map(text -> text), then projected into optional fields:
+- `package`
+- `version`
+- `description`
+- `license`
+- `createdBy`
+
+Unknown metadata keys are ignored.
+
+### 3.3 Default emitted manifest values
+
+Writers in `Wire.hs` currently emit:
+
+- `schema = "arborix.bundle.manifest.v1"`
+- `bundleType = "tree-calculus-executable-object"`
+- `tree.calculus = "tree-calculus.v1"`
+- `tree.nodeHash.algorithm = "sha256"`
+- `tree.nodeHash.domain = "arborix.merkle.node.v1"`
+- `tree.nodePayload = "arborix.merkle.payload.v1"`
+- `runtime.semantics = "tree-calculus.v1"`
+- `runtime.evaluation = "normal-order"`
+- `runtime.abi = "arborix.abi.tree.v1"`
+- `runtime.capabilities = []`
+- `closure = "complete"`
+- `metadata.createdBy = "arborix"`
+
+---
+
+## 4. Nodes section (binary)
+
+Node section payload layout:
+
+```
+node_count: u64 BE
+repeat node_count times:
+  hash: 32 bytes
+  payload_len: u32 BE
+  payload: payload_len bytes
+```
+
+Node payload grammar:
+
+- `0x00`                          => Leaf
+- `0x01 || child_hash(32)`        => Stem
+- `0x02 || left_hash(32)||right(32)` => Fork
+
+Section decoder rejects:
+- duplicate node hashes,
+- truncated entries,
+- payload overruns,
+- trailing bytes after final node.
+
+---
+
+## 5. Verification behavior (`verifyBundle`)
+
+`verifyBundle` enforces all of:
+
+1. bundle version >= 1.
+2. bundle has at least one node.
+3. manifest constants match hardcoded v1 values (schema/type/calculus/hash algo/domain/payload/runtime semantics/ABI).
+4. runtime capabilities must be empty.
+5. closure must be `complete`.
+6. manifest has at least one root and one export.
+7. root sets in `bundleRoots` and `manifest.roots` must match exactly.
+8. each root and export root exists in node map.
+9. each node payload deserializes and re-hashes to declared node hash.
+10. all referenced child hashes exist.
+11. full closure reachability from roots succeeds.
+
+`importBundle` runs decode + verify before storing nodes.
+
+---
+
+## 6. Export/import semantics
+
+### 6.1 Export
+
+`exportNamedBundle`:
+- Traverses reachable nodes for each requested root hash.
+- Builds node map.
+- Builds default manifest and CBOR bytes.
+- Emits two sections (manifest, nodes).
+
+`exportBundle` auto-names exports:
+- 1 root => `root`
+- N>1 => `root0`, `root1`, ...
+
+### 6.2 Import
+
+`importBundle`:
+1. Decode bundle.
+2. Verify bundle.
+3. Insert all node payloads into content store.
+4. For each manifest export: reconstruct tree by export root and store name binding in DB.
+5. Return bundle root list.
+
+---
+
+## 7. Determinism properties
+
+Current implementation is deterministic for identical logical input because:
+- Node map serialized in ascending hash order (`Map.toAscList`).
+- Field order in manifest encoding is fixed by code.
+- Section ordering is fixed: manifest then nodes.
+
+So repeated exports of same roots produce byte-identical bundles.
+
+---
+
+## 8. Known gaps and sane resolutions
+
+These are important design gaps visible from current code.
+
+### Gap A: Node hash domain mismatch risk (critical)
+
+Status: **resolved in current codebase**.
+
+What was wrong:
+- Manifest declared `tree.nodeHash.domain = "arborix.merkle.node.v1"`.
+- Hashing implementation previously used `"tricu.merkle.node.v1"`.
+
+Current state:
+- Haskell hashing now uses `"arborix.merkle.node.v1"`.
+- JS reference runtime hashing now uses `"arborix.merkle.node.v1"`.
+- JS manifest validation now requires `"arborix.merkle.node.v1"`.
+
+Remaining recommendation:
+- Keep hash-domain constants centralized/shared to prevent future drift.
+- Add explicit test vectors for Leaf/Stem/Fork hashes under the Arborix domain.
+
+### Gap B: CBOR decode is order-strict, not generic-map tolerant
+
+Observed:
+- Decoder expects exact key order for most maps.
+
+Impact:
+- Another canonical CBOR writer that reorders keys may decode-fail even if semantically equivalent.
+
+Sane resolution:
+- For v1 compatibility, decode maps as unordered key/value collections, require key presence and types, and reject unknown keys only where desired.
+- Keep writer deterministic, but relax reader.
+
+### Gap C: “Canonical CBOR” claim is stronger than implementation
+
+Observed:
+- Writer uses fixed order but does not explicitly sort keys per RFC 8949 canonical ordering rules.
+
+Sane resolution:
+- Either (a) rename as “deterministic CBOR” profile, or (b) implement explicit canonical key ordering and canonical-length/minimal integer forms checks.
+
+### Gap D: Extra section preservation
+
+Observed:
+- Decoder tolerates unknown non-critical sections, but `Bundle` model/encoder drops them on re-encode.
+
+Sane resolution:
+- Add `bundleExtraSections :: [SectionEntry+Bytes]` if round-trip preservation is desired.
+
+### Gap E: Section version not enforced
+
+Observed:
+- Section entry `Version` is parsed but unused.
+
+Sane resolution:
+- Enforce known version matrix (e.g., manifest v1, nodes v1), or explicitly document “advisory only”.
+
+### Gap F: Runtime capability policy is hard fail
+
+Observed:
+- Any non-empty capabilities list is rejected.
+
+Sane resolution:
+- Keep strict for now, but define capability negotiation strategy for v1.1+ (unknown capabilities => reject unless explicitly allowed by host policy).
+
+### Gap G: Error handling style in import/export path
+
+Observed:
+- Several paths throw `error` for malformed data/store misses.
+
+Sane resolution:
+- Return `Either`-style typed errors through public API (`decode`, `verify`, `import`), reserve exceptions for truly internal faults.
+
+---
+
+## 9. Conformance checklist (v1 current)
+
+A conforming v1 reader/writer for this profile should:
+
+- Implement the 32-byte header and 60-byte section records exactly.
+- Support required sections 1 and 2.
+- Verify section digests with SHA-256.
+- Decode/encode manifest CBOR matching the field model above.
+- Parse nodes section and validate node payload structure.
+- Recompute and verify node hashes.
+- Enforce complete closure for roots.
+- Enforce manifest/runtime constants used by v1.
+
+---
+
+## 10. Suggested follow-up docs
+
+To stabilize interoperability, add:
+
+1. `docs/arborix-bundle-test-vectors.md` (golden header/manifest/nodes + expected hashes).
+2. `docs/arborix-bundle-errors.md` (normative error codes/strings).
+3. `docs/arborix-bundle-evolution.md` (rules for minor/major upgrades, capability negotiation, extra sections).
diff --git a/ext/bundle-runtime-profile-v1.md b/ext/bundle-runtime-profile-v1.md
deleted file mode 100644
index 0f926ce..0000000
--- a/ext/bundle-runtime-profile-v1.md
+++ /dev/null
@@ -1,49 +0,0 @@
-1. Scope
-   This profile defines the minimum required behavior for runtimes that execute tricu bundles.
-
-2. Non-goals
-   No tricu source parsing.
-   No lambda elimination.
-   No module system.
-   No package manager.
-   No local DB requirement.
-   No authoring names beyond bundle exports.
-
-3. Required bundle sections
-   Header
-   Manifest/exports
-   Merkle nodes
-
-4. Optional/skippable sections
-   Source, debug, package metadata, signatures, provenance, etc.
-
-5. Entrypoint selection
-   Explicit export name first.
-   Else export named main.
-   Else single default root.
-   Else error.
-
-6. Node payload format
-   Leaf/Stem/Fork byte layouts.
-
-7. Hash verification
-   Domain string and payload hashing rules.
-
-8. Closure verification
-   All referenced child hashes must exist.
-
-9. Runtime representation
-   Suggested JS representation, but not normative.
-
-10. Reduction semantics
-   The six Tree Calculus apply rules.
-
-11. Codecs for v1
-   Raw tree required.
-   Maybe string/bool optional or experimental.
-
-12. Required error cases
-   Bad magic/version, missing export, hash mismatch, malformed payload, missing child.
-
-13. Test fixtures
-   List of bundles the implementation must pass.
diff --git a/ext/js/src/bundle.js b/ext/js/src/bundle.js
index b58501f..593c6eb 100644
--- a/ext/js/src/bundle.js
+++ b/ext/js/src/bundle.js
@@ -18,9 +18,12 @@
  *     Offset        8B  u64 BE
  *     Length        8B  u64 BE
  *     SHA256Digest 32B raw
+ *   Manifest: canonical CBOR-encoded map (cborg output from Haskell)
+ *   Nodes: binary section
  */
 
 import { createHash } from "node:crypto";
+import { decodeCbor } from "./cbor.js";
 
 // ── Constants ───────────────────────────────────────────────────────────────
 
@@ -170,12 +173,37 @@ export function parseBundle(buffer) {
 }
 
 /**
- * Convenience: parse and return just the manifest JSON.
+ * Post-process a CBOR-decoded manifest to normalize hash fields
+ * from raw bytes to hex strings (matching the old JSON wire format).
+ */
+function normalizeManifest(raw) {
+  const tree = raw.tree;
+  if (tree && tree.nodeHash && tree.nodeHash.domain) {
+    tree.nodeHash.domain = tree.nodeHash.domain;
+  }
+
+  // Convert root hashes from raw bytes to hex
+  const roots = (raw.roots || []).map((r) => ({
+    ...r,
+    hash: r.hash instanceof Uint8Array ? Buffer.from(r.hash).toString("hex") : r.hash,
+  }));
+
+  // Convert export root hashes from raw bytes to hex
+  const exports = (raw.exports || []).map((e) => ({
+    ...e,
+    root: e.root instanceof Uint8Array ? Buffer.from(e.root).toString("hex") : e.root,
+  }));
+
+  return { ...raw, roots, exports };
+}
+
+/**
+ * Convenience: parse and return the manifest from CBOR.
  */
 export function parseManifest(buffer) {
   const bundle = parseBundle(buffer);
   const manifestEntry = bundle.sections.get(SECTION_MANIFEST);
-  return JSON.parse(manifestEntry.data.toString("utf-8"));
+  return normalizeManifest(decodeCbor(manifestEntry.data));
 }
 
 /**
diff --git a/ext/js/src/cbor.js b/ext/js/src/cbor.js
new file mode 100644
index 0000000..9b31f2b
--- /dev/null
+++ b/ext/js/src/cbor.js
@@ -0,0 +1,130 @@
+/**
+ * cbor.js — Minimal CBOR decoder for the Arborix manifest format.
+ *
+ * Decodes the canonical CBOR produced by the Haskell cborg library:
+ *   - Maps: major type 5 (0xa0 + length)
+ *   - Arrays: major type 4 (0x80 + length)
+ *   - Text strings: major type 3, UTF-8 encoded
+ *   - Byte strings: major type 2
+ *   - Unsigned ints: major type 0
+ *   - Simple values: 0xc2 = false, 0xc3 = true
+ *
+ * Only covers the subset needed for the manifest.
+ */
+
+// ── Decoding state ──────────────────────────────────────────────────────────
+
+/**
+ * @param {Buffer} data
+ * @returns {number} remaining buffer
+ */
+function makeDecoder(data) {
+  let offset = 0;
+
+  return {
+    /** @returns {number} current offset */
+    getPos() { return offset; },
+
+    /** @returns {number} remaining bytes */
+    remaining() { return data.length - offset; },
+
+    /** @returns {number} total length */
+    length() { return data.length; },
+
+    /** Read N bytes and advance */
+    read(n) {
+      if (offset + n > data.length) {
+        throw new Error(`CBOR read: expected ${n} bytes, ${data.length - offset} remaining at offset ${offset}`);
+      }
+      const slice = data.slice(offset, offset + n);
+      offset += n;
+      return slice;
+    },
+
+    /** Read a single byte */
+    readByte() {
+      if (offset >= data.length) {
+        throw new Error(`CBOR readByte: no bytes remaining at offset ${offset}`);
+      }
+      return data[offset++];
+    },
+  };
+}
+
+// ── CBOR helpers ────────────────────────────────────────────────────────────
+
+/**
+ * Read a CBOR length (major type initial byte encodes length for values < 24).
+ * For 24+, reads additional bytes per spec.
+ * @returns {number}
+ */
+function cborReadLength(dec, startByte) {
+  const additional = startByte & 0x1f;
+  if (additional < 24) return additional;
+  if (additional === 24) return dec.read(1)[0];
+  if (additional === 25) return dec.read(2).readUint16BE(0);
+  if (additional === 26) return dec.read(4).readUint32BE(0);
+  throw new Error(`CBOR: unsupported additional info ${additional}`);
+}
+
+// ── Top-level decode ────────────────────────────────────────────────────────
+
+/**
+ * Decode a single CBOR value from buffer bytes.
+ * @param {Buffer} buf
+ * @returns {*}
+ */
+export function decodeCbor(buf) {
+  const dec = makeDecoder(buf);
+  const result = cborDecode(dec);
+  return result;
+}
+
+function cborDecode(dec) {
+  const first = dec.readByte();
+  const major = (first >> 5) & 0x07;
+  const info = first & 0x1f;
+
+  switch (major) {
+    case 0: // unsigned int
+    case 1: // negative int
+      return cborReadLength(dec, first);
+
+    case 2: // byte string
+      return dec.read(cborReadLength(dec, first));
+
+    case 3: // text string (UTF-8)
+      const len = cborReadLength(dec, first);
+      return dec.read(len).toString("utf-8");
+
+    case 4: // array
+      const arrLen = cborReadLength(dec, first);
+      const arr = [];
+      for (let i = 0; i < arrLen; i++) {
+        arr.push(cborDecode(dec));
+      }
+      return arr;
+
+    case 5: // map
+      const mapLen = cborReadLength(dec, first);
+      const map = {};
+      for (let i = 0; i < mapLen; i++) {
+        const key = cborDecode(dec);
+        const val = cborDecode(dec);
+        map[key] = val;
+      }
+      return map;
+
+    case 7: // simple values / floats
+      if (info === 20) return false;
+      if (info === 21) return true;
+      if (info === 22) return null; // undefined
+      if (info === 23) return null; // break (shouldn't appear in definite-length)
+      // 0xf9-fb are half/float/double floats — not used by our writer
+      throw new Error(`CBOR: unsupported simple value ${info}`);
+
+    default:
+      // Tags (major 6) and break (0xff) — not used in our manifest
+      throw new Error(`CBOR: unsupported major type ${major}, info ${info}`);
+  }
+}
diff --git a/ext/js/src/manifest.js b/ext/js/src/manifest.js
index 85a3a86..64a5e91 100644
--- a/ext/js/src/manifest.js
+++ b/ext/js/src/manifest.js
@@ -33,7 +33,7 @@ export function validateManifest(manifest) {
       `unsupported node hash algorithm: ${tree.nodeHash.algorithm}`
     );
   }
-  if (tree.nodeHash.domain !== "tricu.merkle.node.v1" && tree.nodeHash.domain !== "arborix.merkle.node.v1") {
+  if (tree.nodeHash.domain !== "arborix.merkle.node.v1") {
     throw new Error(
       `unsupported node hash domain: ${tree.nodeHash.domain}`
     );
diff --git a/ext/js/src/merkle.js b/ext/js/src/merkle.js
index 107e9c2..57f938c 100644
--- a/ext/js/src/merkle.js
+++ b/ext/js/src/merkle.js
@@ -7,14 +7,14 @@
  *   Fork: 0x02 || left_hash (32 bytes raw) || right_hash (32 bytes raw)
  *
  * Hash computation:
- *   hash = SHA256( "tricu.merkle.node.v1" || 0x00 || node_payload )
+ *   hash = SHA256( "arborix.merkle.node.v1" || 0x00 || node_payload )
  */
 
 import { createHash } from "node:crypto";
 
 // ── Constants ───────────────────────────────────────────────────────────────
 
-const DOMAIN_TAG = "tricu.merkle.node.v1";
+const DOMAIN_TAG = "arborix.merkle.node.v1";
 const HASH_LENGTH = 32; // raw hash bytes
 const HEX_LENGTH = 64;  // hex-encoded hash length
 
diff --git a/ext/js/test/bundle.test.js b/ext/js/test/bundle.test.js
index 6445606..26b2830 100644
--- a/ext/js/test/bundle.test.js
+++ b/ext/js/test/bundle.test.js
@@ -1,5 +1,6 @@
 import { readFileSync } from "node:fs";
 import { strictEqual, ok, throws } from "node:assert";
+import { createHash } from "node:crypto";
 import { describe, it } from "node:test";
 import {
   parseBundle,
@@ -13,12 +14,12 @@ import {
   parseNodeSection as parseNodes,
 } from "../src/merkle.js";
 
-const fixtureDir = "test/fixtures";
+const fixtureDir = "../../test/fixtures";
 
 describe("bundle parsing", () => {
   it("valid bundle parses header and sections", () => {
     const bundle = parseBundle(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
     strictEqual(bundle.version, "1.0");
     strictEqual(bundle.sectionCount, 2);
@@ -26,15 +27,16 @@ describe("bundle parsing", () => {
     ok(bundle.sections.has(2)); // nodes
   });
 
-  it("parseManifest returns valid JSON", () => {
+  it("parseManifest returns valid manifest", () => {
     const manifest = parseManifest(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
     strictEqual(manifest.schema, "arborix.bundle.manifest.v1");
     strictEqual(manifest.bundleType, "tree-calculus-executable-object");
     strictEqual(manifest.closure, "complete");
     strictEqual(manifest.tree.calculus, "tree-calculus.v1");
     strictEqual(manifest.tree.nodeHash.algorithm, "sha256");
+    strictEqual(manifest.tree.nodeHash.domain, "arborix.merkle.node.v1");
     strictEqual(manifest.runtime.semantics, "tree-calculus.v1");
     strictEqual(manifest.runtime.abi, "arborix.abi.tree.v1");
   });
@@ -43,7 +45,7 @@ describe("bundle parsing", () => {
 describe("hash verification", () => {
   it("valid bundle nodes verify", () => {
     const data = bundleParseNodeSection(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
     const { nodeMap } = parseNodes(data);
     const { verified } = verifyNodeHashes(nodeMap);
@@ -64,4 +66,69 @@ describe("errors", () => {
     buf.writeUInt16BE(2, 8); // major version 2
     throws(() => parseBundle(buf), /unsupported bundle major version/);
   });
+
+  it("bad section digest fails", () => {
+    const buf = readFileSync(`${fixtureDir}/id.arborix`);
+    // Corrupt one byte in the manifest section
+    buf[152] ^= 0x01;
+    throws(() => parseBundle(buf), /digest mismatch/);
+  });
+
+  it("truncated bundle fails", () => {
+    const buf = readFileSync(`${fixtureDir}/id.arborix`);
+    const truncated = buf.slice(0, 40);
+    throws(() => parseBundle(truncated), /truncated/);
+  });
+
+  it("missing nodes section fails", () => {
+    // Build a bundle with only manifest entry in the directory (1 section instead of 2)
+    const header = Buffer.alloc(32, 0);
+    header.write("ARBORIX\0", 0, 8);
+    header.writeUInt16BE(1, 8);  // major version
+    header.writeUInt16BE(0, 10); // minor version
+    header.writeUInt32BE(1, 12); // 1 section
+
+    // Build a manifest JSON
+    const manifestObj = {
+      schema: "arborix.bundle.manifest.v1",
+      bundleType: "tree-calculus-executable-object",
+      tree: {
+        calculus: "tree-calculus.v1",
+        nodeHash: {
+          algorithm: "sha256",
+          domain: "arborix.merkle.node.v1"
+        },
+        nodePayload: "arborix.merkle.payload.v1"
+      },
+      runtime: {
+        semantics: "tree-calculus.v1",
+        evaluation: "normal-order",
+        abi: "arborix.abi.tree.v1",
+        capabilities: []
+      },
+      closure: "complete",
+      roots: [{ hash: Buffer.alloc(32).toString("hex"), role: "default" }],
+      exports: [{ name: "root", root: Buffer.alloc(32).toString("hex"), kind: "term", abi: "arborix.abi.tree.v1" }],
+      metadata: { createdBy: "arborix" }
+    };
+    const manifestJson = JSON.stringify(manifestObj);
+    const manifestBytes = Buffer.from(manifestJson);
+
+    // Section directory entry (60 bytes, all fields are u64 after the u16s)
+    const entry = Buffer.alloc(60, 0);
+    entry.writeUInt32BE(1, 0);    // type: manifest
+    entry.writeUInt16BE(1, 4);    // version
+    entry.writeUInt16BE(1, 6);    // flags: critical
+    entry.writeUInt16BE(0, 8);    // compression: none
+    entry.writeUInt16BE(1, 10);   // digest algorithm: sha256
+    entry.writeBigUInt64BE(BigInt(32 + 60), 12); // offset (u64)
+    entry.writeBigUInt64BE(BigInt(manifestBytes.length), 20); // length (u64)
+    entry.set(createHash("sha256").update(manifestBytes).digest(), 28); // digest (32 bytes)
+
+    // Set dirOffset to 32 so parseBundle reads directory from after header
+    header.writeBigUInt64BE(BigInt(32), 24);
+
+    const bundleBuf = Buffer.concat([header, entry, manifestBytes]);
+    throws(() => parseBundle(bundleBuf), /missing required section/);
+  });
 });
diff --git a/ext/js/test/merkle.test.js b/ext/js/test/merkle.test.js
index c724fe0..bb233a5 100644
--- a/ext/js/test/merkle.test.js
+++ b/ext/js/test/merkle.test.js
@@ -1,13 +1,14 @@
 import { readFileSync } from "node:fs";
 import { strictEqual, ok } from "node:assert";
 import { describe, it } from "node:test";
-import { parseNodeSection } from "../src/bundle.js";
+import { parseNodeSection as bundleParseNodeSection, parseBundle, parseManifest } from "../src/bundle.js";
 import {
   verifyNodeHashes,
   verifyClosure,
   verifyRootClosure,
   deserializePayload,
   computeNodeHash,
+  parseNodeSection,
 } from "../src/merkle.js";
 
 describe("merkle — deserializePayload", () => {
@@ -49,46 +50,70 @@ describe("merkle — computeNodeHash", () => {
     const hash = computeNodeHash(leaf);
     strictEqual(hash.length, 64);
   });
+
+  it("Leaf hash matches expected Arborix domain", () => {
+    const leaf = { type: "leaf" };
+    const hash = computeNodeHash(leaf);
+    strictEqual(hash, "e54db458aa8e94782f7c61ad6c1f19a1c0c6fca7ffe53674f0d2bc5ff7ab02ff");
+  });
 });
 
 describe("merkle — node section parsing", () => {
-  const fixtureDir = "test/fixtures";
+  const fixtureDir = "../../test/fixtures";
 
-  it("parses id.tri.bundle with correct node count", () => {
-    const data = parseNodeSection(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+  it("parses id.arborix with correct node count", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
-    const { nodeMap } = parseNodes(data);
+    const { nodeMap } = parseNodeSection(data);
     strictEqual(nodeMap.size, 4);
   });
 
-  it("parses true.tri.bundle with correct node count", () => {
-    const data = parseNodeSection(
-      readFileSync(`${fixtureDir}/true.tri.bundle`)
+  it("parses true.arborix with correct node count", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/true.arborix`)
     );
-    const { nodeMap } = parseNodes(data);
+    const { nodeMap } = parseNodeSection(data);
     strictEqual(nodeMap.size, 2);
   });
+
+  it("parses false.arborix with correct node count", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/false.arborix`)
+    );
+    const { nodeMap } = parseNodeSection(data);
+    strictEqual(nodeMap.size, 1);
+  });
 });
 
 describe("merkle — hash verification", () => {
-  const fixtureDir = "test/fixtures";
+  const fixtureDir = "../../test/fixtures";
 
-  it("id.tri.bundle nodes all verify", () => {
-    const data = parseNodeSection(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+  it("id.arborix nodes all verify", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
-    const { nodeMap } = parseNodes(data);
+    const { nodeMap } = parseNodeSection(data);
     const { verified, mismatches } = verifyNodeHashes(nodeMap);
-    ok(verified, "id.tri.bundle node hashes should verify");
+    ok(verified, "id.arborix node hashes should verify");
+    strictEqual(mismatches.length, 0);
+  });
+
+  it("true.arborix nodes all verify", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/true.arborix`)
+    );
+    const { nodeMap } = parseNodeSection(data);
+    const { verified, mismatches } = verifyNodeHashes(nodeMap);
+    ok(verified, "true.arborix node hashes should verify");
     strictEqual(mismatches.length, 0);
   });
 
   it("corrupted node payload fails hash verification", () => {
-    const data = parseNodeSection(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
-    const { nodeMap } = parseNodes(data);
+    const { nodeMap } = parseNodeSection(data);
     // Find a stem node to corrupt
     let stemKey = null;
     for (const [key, node] of nodeMap) {
@@ -110,32 +135,39 @@ describe("merkle — hash verification", () => {
 });
 
 describe("merkle — closure verification", () => {
-  const fixtureDir = "test/fixtures";
+  const fixtureDir = "../../test/fixtures";
 
-  it("id.tri.bundle has complete closure", () => {
-    const data = parseNodeSection(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+  it("id.arborix has complete closure", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
-    const { nodeMap } = parseNodes(data);
+    const { nodeMap } = parseNodeSection(data);
     const { complete, missing } = verifyClosure(nodeMap);
-    ok(complete, "id.tri.bundle should have complete closure");
+    ok(complete, "id.arborix should have complete closure");
     strictEqual(missing.length, 0);
   });
 
   it("verifyRootClosure checks transitive reachability", () => {
-    const data = parseNodeSection(
-      readFileSync(`${fixtureDir}/id.tri.bundle`)
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/id.arborix`)
     );
-    const { nodeMap } = parseNodes(data);
-    const rootHash = "039cc9aacf5be78ec1975713e6ad154a36988e3f3df18589b0d0c801d0825d78";
+    const { nodeMap } = parseNodeSection(data);
+    // Use the actual root hash from the fixture's manifest
+    const manifest = parseManifest(readFileSync(`${fixtureDir}/id.arborix`));
+    const rootHash = manifest.exports[0].root;
     const { complete, missingRoots } = verifyRootClosure(nodeMap, rootHash);
     ok(complete, "root should be reachable");
     strictEqual(missingRoots.length, 0);
   });
-});
 
-// Helper import
-import { parseNodeSection as parseNodes } from "../src/merkle.js";
+  it("parseNodeSection returns correct node count", () => {
+    const data = bundleParseNodeSection(
+      readFileSync(`${fixtureDir}/id.arborix`)
+    );
+    const result = parseNodeSection(data);
+    strictEqual(result.count, 4);
+  });
+});
 
 // Helper for throws
 function throws(fn, expected) {
diff --git a/ext/js/test/run-bundle.test.js b/ext/js/test/run-bundle.test.js
index 854edfc..4a87d45 100644
--- a/ext/js/test/run-bundle.test.js
+++ b/ext/js/test/run-bundle.test.js
@@ -7,10 +7,10 @@ import { validateManifest, selectExport } from "../src/manifest.js";
 import { verifyNodeHashes, parseNodeSection as parseNodes } from "../src/merkle.js";
 import { buildTreeFromNodeMap } from "../src/cli.js";
 
-const fixtureDir = "test/fixtures";
+const fixtureDir = "../../test/fixtures";
 
-describe("run bundle — id.tri.bundle", () => {
-  const bundle = readFileSync(`${fixtureDir}/id.tri.bundle`);
+describe("run bundle — id.arborix", () => {
+  const bundle = readFileSync(`${fixtureDir}/id.arborix`);
   const manifest = parseManifest(bundle);
   const nodeSectionData = bundleParseNodeSection(bundle);
   const { nodeMap } = parseNodes(nodeSectionData);
@@ -24,25 +24,21 @@ describe("run bundle — id.tri.bundle", () => {
     ok(verified);
   });
 
-  it("export 'id' is selectable", () => {
-    const exp = selectExport(manifest, "id");
-    strictEqual(exp.name, "id");
+  it("export 'root' is selectable", () => {
+    const exp = selectExport(manifest, "root");
+    strictEqual(exp.name, "root");
   });
 
   it("tree reconstructs as a Fork", () => {
-    const exp = selectExport(manifest, "id");
+    const exp = selectExport(manifest, "root");
     const tree = buildTreeFromNodeMap(nodeMap, exp.root);
     ok(Array.isArray(tree));
-    // id = t (t t) = Fork (Stem Leaf) Leaf... 
-    // In Haskell: id = S = t (t (t t)) t
-    // This is Fork (Fork (Fork Leaf Leaf) Leaf) Leaf
-    // In array form: [[[], []], [], []]
     ok(tree.length >= 2, "tree should be a Fork (length >= 2)");
   });
 });
 
-describe("run bundle — true.tri.bundle", () => {
-  const bundle = readFileSync(`${fixtureDir}/true.tri.bundle`);
+describe("run bundle — true.arborix", () => {
+  const bundle = readFileSync(`${fixtureDir}/true.arborix`);
   const manifest = parseManifest(bundle);
   const nodeSectionData = bundleParseNodeSection(bundle);
   const { nodeMap } = parseNodes(nodeSectionData);
@@ -51,20 +47,60 @@ describe("run bundle — true.tri.bundle", () => {
     validateManifest(manifest);
   });
 
-  it("export 'const' is selectable", () => {
-    const exp = selectExport(manifest, "const");
-    strictEqual(exp.name, "const");
+  it("export 'root' is selectable", () => {
+    const exp = selectExport(manifest, "root");
+    strictEqual(exp.name, "root");
   });
 
-  it("tree reconstructs", () => {
-    const exp = selectExport(manifest, "const");
+  it("tree reconstructs as Stem Leaf", () => {
+    const exp = selectExport(manifest, "root");
     const tree = buildTreeFromNodeMap(nodeMap, exp.root);
     ok(Array.isArray(tree));
+    strictEqual(tree.length, 1, "true should be a Stem (single child)");
+    strictEqual(tree[0].length, 0, "child should be Leaf");
+  });
+});
+
+describe("run bundle — false.arborix", () => {
+  const bundle = readFileSync(`${fixtureDir}/false.arborix`);
+  const manifest = parseManifest(bundle);
+  const nodeSectionData = bundleParseNodeSection(bundle);
+  const { nodeMap } = parseNodes(nodeSectionData);
+
+  it("manifest validates", () => {
+    validateManifest(manifest);
+  });
+
+  it("export 'root' is selectable", () => {
+    const exp = selectExport(manifest, "root");
+    strictEqual(exp.name, "root");
+  });
+
+  it("tree reconstructs as Leaf", () => {
+    const exp = selectExport(manifest, "root");
+    const tree = buildTreeFromNodeMap(nodeMap, exp.root);
+    strictEqual(tree.length, 0, "false should be Leaf (empty array)");
+  });
+});
+
+describe("run bundle — notQ.arborix", () => {
+  const bundle = readFileSync(`${fixtureDir}/notQ.arborix`);
+  const manifest = parseManifest(bundle);
+  const nodeSectionData = bundleParseNodeSection(bundle);
+  const { nodeMap } = parseNodes(nodeSectionData);
+
+  it("manifest validates", () => {
+    validateManifest(manifest);
+  });
+
+  it("node hashes verify", () => {
+    const { verified } = verifyNodeHashes(nodeMap);
+    ok(verified);
   });
 });
 
 describe("run bundle — missing export", () => {
-  const bundle = readFileSync(`${fixtureDir}/id.tri.bundle`);
+  const bundle = readFileSync(`${fixtureDir}/id.arborix`);
   const manifest = parseManifest(bundle);
 
   it("nonexistent export fails clearly", () => {
@@ -73,8 +109,8 @@ describe("run bundle — missing export", () => {
 });
 
 describe("run bundle — auto-select", () => {
-  // true.tri.bundle has only one export, should auto-select
-  const bundle = readFileSync(`${fixtureDir}/true.tri.bundle`);
+  // true.arborix has only one export, should auto-select
+  const bundle = readFileSync(`${fixtureDir}/true.arborix`);
   const manifest = parseManifest(bundle);
 
   it("single export auto-selects", () => {
diff --git a/flake.nix b/flake.nix
index 5aca8da..acc7401 100644
--- a/flake.nix
+++ b/flake.nix
@@ -18,9 +18,14 @@
 
         tricuStatic = hsLib.justStaticExecutables self.packages.${system}.default;
 
-        tricuPackage =
+        tricuPackageTests =
           haskellPackages.callCabal2nix packageName self {};
 
+        tricuPackage =
+          hsLib.dontCheck (
+            haskellPackages.callCabal2nix packageName self {}
+          );
+
         customGHC = haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
           megaparsec
         ]);
@@ -28,8 +33,8 @@
         packages.${packageName} = tricuPackage;
         packages.default = tricuPackage;
 
-        checks.${packageName} = tricuPackage;
-        checks.default = tricuPackage;
+        checks.${packageName} = tricuPackageTests;
+        checks.default = tricuPackageTests;
 
         defaultPackage = self.packages.${system}.default;
 
diff --git a/src/Research.hs b/src/Research.hs
index 86101a3..e20b581 100644
--- a/src/Research.hs
+++ b/src/Research.hs
@@ -85,12 +85,12 @@ serializeNode (NFork l r) = BS.pack [0x02] <> go (decode (encodeUtf8 l)) <> go (
         go (Right bs) = bs
 
 -- | Hash a node per the Merkle content-addressing spec.
--- hash = SHA256( "tricu.merkle.node.v1" <> 0x00 <> node_payload )
+-- hash = SHA256( "arborix.merkle.node.v1" <> 0x00 <> node_payload )
 nodeHash :: Node -> MerkleHash
 nodeHash node = decodeUtf8 (encode (sha256WithPrefix (serializeNode node)))
   where sha256WithPrefix payload =
           convert . (hash :: BS.ByteString -> Digest SHA256) $ utf8Tag <> BS.pack [0x00] <> payload
-        utf8Tag = BS.pack $ map fromIntegral $ BS.unpack "tricu.merkle.node.v1"
+        utf8Tag = BS.pack $ map fromIntegral $ BS.unpack "arborix.merkle.node.v1"
 
 -- | Deserialize a Node from canonical bytes.
 deserializeNode :: BS.ByteString -> Node
diff --git a/src/Wire.hs b/src/Wire.hs
index 82ba2bb..836a5b8 100644
--- a/src/Wire.hs
+++ b/src/Wire.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Wire
   ( Bundle (..)
@@ -8,7 +9,7 @@ module Wire
   , RuntimeSpec (..)
   , BundleRoot (..)
   , BundleExport (..)
-  , BundleMetadata (..)
+  , BundleMetadata
   , ClosureMode (..)
   , encodeBundle
   , decodeBundle
@@ -23,21 +24,26 @@ module Wire
 import ContentStore (getNodeMerkle, loadTree, putMerkleNode, storeTerm)
 import Research
 
+import Codec.CBOR.Decoding ( Decoder
+                           , decodeString
+                           , decodeBytes
+                           , decodeListLen
+                           , decodeMapLen
+                           )
+import Control.Monad (replicateM, forM)
+import Codec.CBOR.Encoding ( Encoding
+                           , encodeMapLen
+                           , encodeListLen
+                           , encodeString
+                           , encodeBytes
+                           )
+import Codec.CBOR.Write (toLazyByteString)
+import Data.Monoid (mconcat)
+import Codec.CBOR.Read (deserialiseFromBytes, DeserialiseFailure(..))
+
 import Control.Exception (SomeException, evaluate, try)
 import Control.Monad (foldM, unless, when)
 import Crypto.Hash (Digest, SHA256, hash)
-import Data.Aeson ( FromJSON (..)
-                  , ToJSON (..)
-                  , Value (String)
-                  , eitherDecodeStrict'
-                  , encode
-                  , object
-                  , withObject
-                  , (.:)
-                  , (.:?)
-                  , (.!=)
-                  , (.=)
-                  )
 import Data.Bits ((.&.), (.|.), shiftL, shiftR)
 import Data.ByteArray (convert)
 import Data.ByteString (ByteString)
@@ -84,54 +90,121 @@ compressionNone, digestSha256 :: Word16
 compressionNone = 0
 digestSha256 = 1
 
--- | Closure declaration. V1 only accepts complete bundles for import.
+-- ---------------------------------------------------------------------------
+-- CBOR encoding helpers
+-- ---------------------------------------------------------------------------
+
+-- | Canonical CBOR map length encoder.
+cmkLen :: Int -> Encoding
+cmkLen n = encodeMapLen (fromIntegral n)
+
+-- | Decode a CBOR array of n elements.
+decodeListN :: Decoder s a -> Int -> Decoder s [a]
+decodeListN dec n = replicateM n dec
+
+-- | Decode a CBOR map (sequence of key-value pairs).
+decodeMapN :: Decoder s a -> Decoder s b -> Int -> Decoder s [(a, b)]
+decodeMapN keyDec valDec n = forM [1..n] $ \_ ->
+  keyDec >>= \k -> valDec >>= \v -> pure (k, v)
+
+decodeKey :: Text -> Decoder s ()
+decodeKey expected = do
+  actual <- decodeString
+  unless (actual == expected) $
+    fail $ "expected key " ++ show expected ++ ", got " ++ show actual
+
+-- | Canonical CBOR array length encoder.
+cakLen :: Int -> Encoding
+cakLen n = encodeListLen (fromIntegral n)
+
+-- | Encode a canonical CBOR map with key-value pairs as flat sequence.
+cmkPairs :: [(Text, Encoding)] -> Encoding
+cmkPairs [] = cmkLen 0
+cmkPairs kvs = cmkLen (length kvs) <> mconcat [encodeString k <> v | (k, v) <- kvs]
+
+-- | Encode a canonical CBOR array.
+cakSeq :: [Encoding] -> Encoding
+cakSeq [] = cakLen 0
+cakSeq xs = cakLen (length xs) <> mconcat xs
+
+-- | Encode a canonical CBOR text string.
+encText :: Text -> Encoding
+encText = encodeString
+
+-- | Encode a canonical CBOR byte string.
+encBytes :: ByteString -> Encoding
+encBytes = encodeBytes
+
+-- ---------------------------------------------------------------------------
+-- Data types with CBOR instances
+-- ---------------------------------------------------------------------------
+
+-- | Closure declaration.
 data ClosureMode = ClosureComplete | ClosurePartial
   deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON ClosureMode where
-  toJSON ClosureComplete = String "complete"
-  toJSON ClosurePartial = String "partial"
+toCBORClosure :: ClosureMode -> Encoding
+toCBORClosure = encText . \case
+  ClosureComplete -> "complete"
+  ClosurePartial  -> "partial"
 
-instance FromJSON ClosureMode where
-  parseJSON (String "complete") = pure ClosureComplete
-  parseJSON (String "partial") = pure ClosurePartial
-  parseJSON _ = fail "closure must be \"complete\" or \"partial\""
+closureFromCBOR :: Decoder s ClosureMode
+closureFromCBOR = decodeString >>= \case
+  "complete" -> pure ClosureComplete
+  "partial"  -> pure ClosurePartial
+  other -> fail $ "ClosureMode: " ++ show other
 
+-- | Hash specification (algorithm + domain strings).
 data NodeHashSpec = NodeHashSpec
   { nodeHashAlgorithm :: Text
   , nodeHashDomain :: Text
   } deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON NodeHashSpec where
-  toJSON s = object
-    [ "algorithm" .= nodeHashAlgorithm s
-    , "domain" .= nodeHashDomain s
+toCBORNodeHashSpec :: NodeHashSpec -> Encoding
+toCBORNodeHashSpec (NodeHashSpec alg dom) =
+  cmkPairs
+    [ ("algorithm", encText alg)
+    , ("domain",    encText dom)
     ]
 
-instance FromJSON NodeHashSpec where
-  parseJSON = withObject "NodeHashSpec" $ \o -> NodeHashSpec
-    <$> o .: "algorithm"
-    <*> o .: "domain"
+nodeHashSpecFromCBOR :: Decoder s NodeHashSpec
+nodeHashSpecFromCBOR = do
+  n <- decodeMapLen
+  unless (n == 2) $ fail "NodeHashSpec: must have exactly 2 entries"
+  decodeKey "algorithm"
+  alg <- decodeString
+  decodeKey "domain"
+  dom <- decodeString
+  pure (NodeHashSpec alg dom)
 
+-- | Tree specification.
 data TreeSpec = TreeSpec
   { treeCalculus :: Text
   , treeNodeHash :: NodeHashSpec
   , treeNodePayload :: Text
   } deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON TreeSpec where
-  toJSON s = object
-    [ "calculus" .= treeCalculus s
-    , "nodeHash" .= treeNodeHash s
-    , "nodePayload" .= treeNodePayload s
+toCBORTreeSpec :: TreeSpec -> Encoding
+toCBORTreeSpec (TreeSpec calc hspec payload) =
+  cmkPairs
+    [ ("calculus",    encText calc)
+    , ("nodeHash",    toCBORNodeHashSpec hspec)
+    , ("nodePayload", encText payload)
     ]
 
-instance FromJSON TreeSpec where
-  parseJSON = withObject "TreeSpec" $ \o -> TreeSpec
-    <$> o .: "calculus"
-    <*> o .: "nodeHash"
-    <*> o .: "nodePayload"
+treeSpecFromCBOR :: Decoder s TreeSpec
+treeSpecFromCBOR = do
+  n <- decodeMapLen
+  unless (n == 3) $ fail "TreeSpec: must have exactly 3 entries"
+  decodeKey "calculus"
+  calc <- decodeString
+  decodeKey "nodeHash"
+  hspec <- nodeHashSpecFromCBOR
+  decodeKey "nodePayload"
+  payload <- decodeString
+  pure (TreeSpec calc hspec payload)
 
+-- | Runtime specification.
 data RuntimeSpec = RuntimeSpec
   { runtimeSemantics :: Text
   , runtimeEvaluation :: Text
@@ -139,65 +212,85 @@ data RuntimeSpec = RuntimeSpec
   , runtimeCapabilities :: [Text]
   } deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON RuntimeSpec where
-  toJSON s = object
-    [ "semantics" .= runtimeSemantics s
-    , "evaluation" .= runtimeEvaluation s
-    , "abi" .= runtimeAbi s
-    , "capabilities" .= runtimeCapabilities s
+toCBORRuntimeSpec :: RuntimeSpec -> Encoding
+toCBORRuntimeSpec (RuntimeSpec sem eval abi caps) =
+  cmkPairs
+    [ ("semantics",   encText sem)
+    , ("evaluation",  encText eval)
+    , ("abi",         encText abi)
+    , ("capabilities", cakSeq (map encText caps))
     ]
 
-instance FromJSON RuntimeSpec where
-  parseJSON = withObject "RuntimeSpec" $ \o -> RuntimeSpec
-    <$> o .: "semantics"
-    <*> o .: "evaluation"
-    <*> o .: "abi"
-    <*> o .:? "capabilities" .!= []
+runtimeSpecFromCBOR :: Decoder s RuntimeSpec
+runtimeSpecFromCBOR = do
+  n <- decodeMapLen
+  unless (n == 4) $ fail "RuntimeSpec: must have exactly 4 entries"
+  decodeKey "semantics"
+  sem <- decodeString
+  decodeKey "evaluation"
+  eval <- decodeString
+  decodeKey "abi"
+  abi <- decodeString
+  decodeKey "capabilities"
+  clen <- decodeListLen
+  caps <- decodeListN decodeString clen
+  pure (RuntimeSpec sem eval abi caps)
 
+-- | A root hash reference.
 data BundleRoot = BundleRoot
   { rootHash :: MerkleHash
   , rootRole :: Text
   } deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON BundleRoot where
-  toJSON r = object
-    [ "hash" .= rootHash r
-    , "role" .= rootRole r
+toCBORBundleRoot :: BundleRoot -> Encoding
+toCBORBundleRoot (BundleRoot h role) =
+  cmkPairs
+    [ ("hash",  encBytes (merkleHashToRaw h))
+    , ("role",  encText role)
     ]
 
-instance FromJSON BundleRoot where
-  parseJSON = withObject "BundleRoot" $ \o -> BundleRoot
-    <$> o .: "hash"
-    <*> o .:? "role" .!= "root"
+bundleRootFromCBOR :: Decoder s BundleRoot
+bundleRootFromCBOR = do
+  n <- decodeMapLen
+  unless (n == 2) $ fail "BundleRoot: must have exactly 2 entries"
+  decodeKey "hash"
+  hRaw <- decodeBytes
+  decodeKey "role"
+  role <- decodeString
+  pure (BundleRoot (rawToMerkleHash hRaw) role)
 
+-- | An export entry.
 data BundleExport = BundleExport
   { exportName :: Text
   , exportRoot :: MerkleHash
   , exportKind :: Text
   , exportAbi :: Text
-  , exportInput :: Maybe Text
-  , exportOutput :: Maybe Text
   } deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON BundleExport where
-  toJSON e = object
-    [ "name" .= exportName e
-    , "root" .= exportRoot e
-    , "kind" .= exportKind e
-    , "abi" .= exportAbi e
-    , "input" .= exportInput e
-    , "output" .= exportOutput e
+toCBORBundleExport :: BundleExport -> Encoding
+toCBORBundleExport (BundleExport name h kind abi) =
+  cmkPairs
+    [ ("name", encText name)
+    , ("root", encBytes (merkleHashToRaw h))
+    , ("kind", encText kind)
+    , ("abi",  encText abi)
     ]
 
-instance FromJSON BundleExport where
-  parseJSON = withObject "BundleExport" $ \o -> BundleExport
-    <$> o .: "name"
-    <*> o .: "root"
-    <*> o .:? "kind" .!= "term"
-    <*> o .:? "abi" .!= "arborix.abi.tree.v1"
-    <*> o .:? "input"
-    <*> o .:? "output"
+bundleExportFromCBOR :: Decoder s BundleExport
+bundleExportFromCBOR = do
+  n <- decodeMapLen
+  unless (n == 4) $ fail "BundleExport: must have exactly 4 entries"
+  decodeKey "name"
+  name <- decodeString
+  decodeKey "root"
+  hRaw <- decodeBytes
+  decodeKey "kind"
+  kind <- decodeString
+  decodeKey "abi"
+  abi <- decodeString
+  pure (BundleExport name (rawToMerkleHash hRaw) kind abi)
 
+-- | Optional package metadata.
 data BundleMetadata = BundleMetadata
   { metadataPackage :: Maybe Text
   , metadataVersion :: Maybe Text
@@ -206,23 +299,34 @@ data BundleMetadata = BundleMetadata
   , metadataCreatedBy :: Maybe Text
   } deriving (Show, Eq, Ord, Generic)
 
-instance ToJSON BundleMetadata where
-  toJSON m = object
-    [ "package" .= metadataPackage m
-    , "version" .= metadataVersion m
-    , "description" .= metadataDescription m
-    , "license" .= metadataLicense m
-    , "createdBy" .= metadataCreatedBy m
-    ]
+metadataFromCBOR :: Decoder s BundleMetadata
+metadataFromCBOR = do
+  mlen <- decodeMapLen
+  entries <- decodeMapN decodeString decodeString mlen
+  let lookupText k = go k entries
+      go _ [] = Nothing
+      go k ((k', v):rest)
+        | k == k'   = Just v
+        | otherwise = go k rest
+  pure BundleMetadata
+    { metadataPackage   = lookupText "package"
+    , metadataVersion   = lookupText "version"
+    , metadataDescription = lookupText "description"
+    , metadataLicense   = lookupText "license"
+    , metadataCreatedBy = lookupText "createdBy"
+    }
 
-instance FromJSON BundleMetadata where
-  parseJSON = withObject "BundleMetadata" $ \o -> BundleMetadata
-    <$> o .:? "package"
-    <*> o .:? "version"
-    <*> o .:? "description"
-    <*> o .:? "license"
-    <*> o .:? "createdBy"
+metadataToCBOR :: BundleMetadata -> Encoding
+metadataToCBOR (BundleMetadata pkg ver desc lic by) =
+  let pairs =
+        maybe [] (\v -> [("package", encText v)]) pkg
+        ++ maybe [] (\v -> [("version", encText v)]) ver
+        ++ maybe [] (\v -> [("description", encText v)]) desc
+        ++ maybe [] (\v -> [("license", encText v)]) lic
+        ++ maybe [] (\v -> [("createdBy", encText v)]) by
+  in cmkPairs pairs
 
+-- | The manifest: top-level bundle metadata.
 data BundleManifest = BundleManifest
   { manifestSchema :: Text
   , manifestBundleType :: Text
@@ -231,37 +335,45 @@ data BundleManifest = BundleManifest
   , manifestClosure :: ClosureMode
   , manifestRoots :: [BundleRoot]
   , manifestExports :: [BundleExport]
-  , manifestImports :: [Value]
-  , manifestSections :: Value
   , manifestMetadata :: BundleMetadata
   } deriving (Show, Eq, Generic)
 
-instance ToJSON BundleManifest where
-  toJSON m = object
-    [ "schema" .= manifestSchema m
-    , "bundleType" .= manifestBundleType m
-    , "tree" .= manifestTree m
-    , "runtime" .= manifestRuntime m
-    , "closure" .= manifestClosure m
-    , "roots" .= manifestRoots m
-    , "exports" .= manifestExports m
-    , "imports" .= manifestImports m
-    , "sections" .= manifestSections m
-    , "metadata" .= manifestMetadata m
+manifestToCBOR :: BundleManifest -> Encoding
+manifestToCBOR m =
+  cmkPairs
+    [ ("schema",     encText (manifestSchema m))
+    , ("bundleType", encText (manifestBundleType m))
+    , ("tree",       toCBORTreeSpec (manifestTree m))
+    , ("runtime",    toCBORRuntimeSpec (manifestRuntime m))
+    , ("closure",    toCBORClosure (manifestClosure m))
+    , ("roots",      cakSeq (map toCBORBundleRoot (manifestRoots m)))
+    , ("exports",    cakSeq (map toCBORBundleExport (manifestExports m)))
+    , ("metadata",   metadataToCBOR (manifestMetadata m))
     ]
 
-instance FromJSON BundleManifest where
-  parseJSON = withObject "BundleManifest" $ \o -> BundleManifest
-    <$> o .: "schema"
-    <*> o .: "bundleType"
-    <*> o .: "tree"
-    <*> o .: "runtime"
-    <*> o .: "closure"
-    <*> o .: "roots"
-    <*> o .: "exports"
-    <*> o .:? "imports" .!= []
-    <*> o .:? "sections" .!= object []
-    <*> o .:? "metadata" .!= BundleMetadata Nothing Nothing Nothing Nothing Nothing
+manifestFromCBOR :: Decoder s BundleManifest
+manifestFromCBOR = do
+  n <- decodeMapLen
+  unless (n == 8) $ fail "BundleManifest: must have exactly 8 entries"
+  decodeKey "schema"
+  schema <- decodeString
+  decodeKey "bundleType"
+  bundleType <- decodeString
+  decodeKey "tree"
+  tree <- treeSpecFromCBOR
+  decodeKey "runtime"
+  runtime <- runtimeSpecFromCBOR
+  decodeKey "closure"
+  closure <- closureFromCBOR
+  decodeKey "roots"
+  rlen <- decodeListLen
+  roots <- decodeListN bundleRootFromCBOR rlen
+  decodeKey "exports"
+  elen <- decodeListLen
+  exports <- decodeListN bundleExportFromCBOR elen
+  decodeKey "metadata"
+  metadata <- metadataFromCBOR
+  pure (BundleManifest schema bundleType tree runtime closure roots exports metadata)
 
 -- | Portable executable-object bundle.
 --
@@ -276,12 +388,33 @@ data Bundle = Bundle
   , bundleManifestBytes :: ByteString
   } deriving (Show, Eq)
 
+-- ---------------------------------------------------------------------------
+-- CBOR manifest serialization
+-- ---------------------------------------------------------------------------
+
+-- | Encode the manifest as canonical CBOR.
+encodeManifest :: BundleManifest -> ByteString
+encodeManifest m = BL.toStrict (toLazyByteString (manifestToCBOR m))
+
+-- | Decode a manifest from CBOR bytes.
+decodeManifest :: ByteString -> Either String BundleManifest
+decodeManifest bs =
+  case deserialiseFromBytes manifestFromCBOR (BL.fromStrict bs) of
+    Right (rest, m)
+      | BS.null (BL.toStrict rest) -> Right m
+      | otherwise -> Left "trailing bytes after manifest CBOR"
+    Left (DeserialiseFailure _ msg) -> Left msg
+
+-- ---------------------------------------------------------------------------
+-- Bundle encoding
+-- ---------------------------------------------------------------------------
+
 -- | Encode a Bundle to portable Bundle v1 bytes.
 encodeBundle :: Bundle -> ByteString
 encodeBundle bundle =
   let nodeSection = encodeNodeSection (bundleNodes bundle)
       manifestBytes = if BS.null (bundleManifestBytes bundle)
-        then BL.toStrict (encode (bundleManifest bundle))
+        then encodeManifest (bundleManifest bundle)
         else bundleManifestBytes bundle
       sectionCount = 2
       dirOffset = fromIntegral headerLength
@@ -346,15 +479,14 @@ decodePortableBundle bs = do
       dirBytes = fromIntegral sectionCount * sectionEntryLength
   when (BS.length bs < dirStart + dirBytes) $
     Left "bundle truncated in section directory"
-  entries <- decodeSectionEntries sectionCount (BS.take dirBytes $ BS.drop dirStart bs)
+  let dirRaw = BS.take dirBytes $ BS.drop dirStart bs
+  entries <- decodeSectionEntries sectionCount dirRaw
   traverse_ rejectUnknownCritical entries
   manifestEntry <- requireSection sectionManifest entries
   nodesEntry <- requireSection sectionNodes entries
   manifestBytes <- readAndVerifySection bs manifestEntry
   nodesBytes <- readAndVerifySection bs nodesEntry
-  manifest <- case eitherDecodeStrict' manifestBytes of
-    Left err -> Left $ "invalid manifest JSON: " ++ err
-    Right m -> Right m
+  manifest <- decodeManifest manifestBytes
   nodes <- decodeNodeSection nodesBytes
   let roots = map rootHash (manifestRoots manifest)
   return Bundle
@@ -429,8 +561,8 @@ decodeSectionEntries count bytes = reverse <$> go count bytes []
 -- Manifest construction
 -- ---------------------------------------------------------------------------
 
-defaultManifest :: [(Text, MerkleHash)] -> Int -> BundleManifest
-defaultManifest namedRoots nodeCount = BundleManifest
+defaultManifest :: [(Text, MerkleHash)] -> BundleManifest
+defaultManifest namedRoots = BundleManifest
   { manifestSchema = "arborix.bundle.manifest.v1"
   , manifestBundleType = "tree-calculus-executable-object"
   , manifestTree = TreeSpec
@@ -450,18 +582,11 @@ defaultManifest namedRoots nodeCount = BundleManifest
   , manifestClosure = ClosureComplete
   , manifestRoots = zipWith mkRoot [0 :: Int ..] (map snd namedRoots)
   , manifestExports = map mkExport namedRoots
-  , manifestImports = []
-  , manifestSections = object
-      [ "nodes" .= object
-          [ "count" .= nodeCount
-          , "payload" .= ("arborix.merkle.payload.v1" :: Text)
-          ]
-      ]
   , manifestMetadata = BundleMetadata
-      { metadataPackage = Nothing
-      , metadataVersion = Nothing
+      { metadataPackage   = Nothing
+      , metadataVersion   = Nothing
       , metadataDescription = Nothing
-      , metadataLicense = Nothing
+      , metadataLicense   = Nothing
       , metadataCreatedBy = Just "arborix"
       }
   }
@@ -473,8 +598,6 @@ defaultManifest namedRoots nodeCount = BundleManifest
       , exportRoot = h
       , exportKind = "term"
       , exportAbi = "arborix.abi.tree.v1"
-      , exportInput = Nothing
-      , exportOutput = Nothing
       }
 
 -- ---------------------------------------------------------------------------
@@ -568,12 +691,10 @@ verifyManifest manifest = do
     Left $ "unsupported runtime semantics: " ++ unpack (runtimeSemantics runtimeSpec)
   when (runtimeAbi runtimeSpec /= "arborix.abi.tree.v1") $
     Left $ "unsupported runtime ABI: " ++ unpack (runtimeAbi runtimeSpec)
-  unless (null $ runtimeCapabilities runtimeSpec) $
-    Left "host/runtime capabilities are not supported by bundle v1"
+  when (not (null (runtimeCapabilities runtimeSpec))) $
+    Left "unsupported runtime capabilities"
   when (manifestClosure manifest /= ClosureComplete) $
-    Left "bundle v1 imports require closure = complete"
-  unless (null $ manifestImports manifest) $
-    Left "bundle v1 imports require an empty imports list"
+    Left "bundle v1 requires closure = complete"
   when (null $ manifestRoots manifest) $
     Left "manifest has no roots"
   when (null $ manifestExports manifest) $
@@ -674,8 +795,8 @@ exportNamedBundle conn namedHashes = do
   let hashes = map snd namedHashes
   entries <- concat <$> mapM (collectReachableNodes conn) hashes
   let nodeMap = Map.fromList entries
-      manifest = defaultManifest namedHashes (Map.size nodeMap)
-      manifestBytes = BL.toStrict (encode manifest)
+      manifest = defaultManifest namedHashes
+      manifestBytes = encodeManifest manifest
       bundle = Bundle
         { bundleVersion = bundleMajorVersion * 1000 + bundleMinorVersion
         , bundleRoots = hashes
@@ -793,6 +914,8 @@ rawToMerkleHash bs = decodeUtf8 (Base16.encode bs)
 sha256 :: ByteString -> ByteString
 sha256 bytes = convert ((hash bytes) :: Digest SHA256)
 
+
+
 defaultExportNames :: Int -> [Text]
 defaultExportNames n =
   case n of
diff --git a/test/Spec.hs b/test/Spec.hs
index 8f3687d..23a119d 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -2041,7 +2041,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
       result env @?= okT Leaf (bytesT ([101,102,103] ++ nodesBytes))
 
   , testCase "readArborixNodesSection: reads id fixture bundle" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/id.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/id.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right _ -> do
@@ -2053,7 +2053,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
           result env @?= ofNumber 0
 
   , testCase "readArborixNodesSection: reads notQ fixture bundle" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/notQ.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/notQ.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right _ -> do
@@ -2065,7 +2065,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
           result env @?= ofNumber 0
 
   , testCase "readArborixNodesSection: reads map fixture bundle" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/map.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/map.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right _ -> do
@@ -2077,7 +2077,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
           result env @?= ofNumber 0
 
   , testCase "readArborixExecutableFromHash: reconstructs id fixture root" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/id.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/id.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
@@ -2093,7 +2093,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
             result env @?= ofNumber 0
 
   , testCase "readArborixExecutableFromHash: reconstructs notQ fixture root" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/notQ.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/notQ.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
@@ -2109,7 +2109,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
             result env @?= ofNumber 0
 
   , testCase "readArborixExecutableFromHash: reconstructs map fixture root" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/map.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/map.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
@@ -2125,7 +2125,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
             result env @?= ofNumber 0
 
   , testCase "readArborixExecutableFromHash: executes id fixture root" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/id.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/id.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
@@ -2141,7 +2141,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
             result env @?= ofNumber 42
 
   , testCase "readArborixExecutableFromHash: executes notQ fixture on true" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/notQ.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/notQ.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
@@ -2157,7 +2157,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
             result env @?= falseT
 
   , testCase "readArborixExecutableFromHash: executes notQ fixture on false" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/notQ.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/notQ.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
@@ -2173,7 +2173,7 @@ binaryReaderTests = testGroup "Binary Reader Tests"
             result env @?= trueT
 
   , testCase "readArborixExecutableFromHash: executes map fixture root" $ do
-      fixtureBytes <- BS.readFile "test/fixtures/map.tri.bundle"
+      fixtureBytes <- BS.readFile "test/fixtures/map.arborix"
       case decodeBundle fixtureBytes of
         Left err -> assertFailure $ "decodeBundle failed: " ++ err
         Right bundle -> case bundleRoots bundle of
diff --git a/test/fixtures/false.arborix b/test/fixtures/false.arborix
new file mode 100644
index 0000000..53816b3
Binary files /dev/null and b/test/fixtures/false.arborix differ
diff --git a/test/fixtures/id.arborix b/test/fixtures/id.arborix
new file mode 100644
index 0000000..deb7f5e
Binary files /dev/null and b/test/fixtures/id.arborix differ
diff --git a/test/fixtures/id.tri.bundle b/test/fixtures/id.tri.bundle
deleted file mode 100644
index 47589dc..0000000
Binary files a/test/fixtures/id.tri.bundle and /dev/null differ
diff --git a/test/fixtures/map.arborix b/test/fixtures/map.arborix
new file mode 100644
index 0000000..e3d4e43
Binary files /dev/null and b/test/fixtures/map.arborix differ
diff --git a/test/fixtures/map.tri.bundle b/test/fixtures/map.tri.bundle
deleted file mode 100644
index e3014a4..0000000
Binary files a/test/fixtures/map.tri.bundle and /dev/null differ
diff --git a/test/fixtures/notQ.arborix b/test/fixtures/notQ.arborix
new file mode 100644
index 0000000..3d1b7e8
Binary files /dev/null and b/test/fixtures/notQ.arborix differ
diff --git a/test/fixtures/notQ.tri.bundle b/test/fixtures/notQ.tri.bundle
deleted file mode 100644
index 2cbb59d..0000000
Binary files a/test/fixtures/notQ.tri.bundle and /dev/null differ
diff --git a/test/fixtures/true.arborix b/test/fixtures/true.arborix
new file mode 100644
index 0000000..4fb2275
Binary files /dev/null and b/test/fixtures/true.arborix differ
diff --git a/tricu.cabal b/tricu.cabal
index 8e97dfa..46f5fd2 100644
--- a/tricu.cabal
+++ b/tricu.cabal
@@ -37,11 +37,11 @@ executable tricu
     -fPIC
   build-depends:
     base >=4.7
-    , aeson
     , ansi-terminal
     , base16-bytestring
     , base64-bytestring
     , bytestring
+    , cborg
     , cmdargs
     , containers
     , cryptonite
@@ -90,11 +90,11 @@ test-suite tricu-tests
       ScopedTypeVariables
   build-depends:       
     base >=4.7
-    , aeson
     , ansi-terminal
     , base16-bytestring
     , base64-bytestring
     , bytestring
+    , cborg
     , cmdargs
     , containers
     , cryptonite
@@ -115,8 +115,8 @@ test-suite tricu-tests
     , text
     , time
     , transformers
-    , warp
     , wai
+    , warp
     , zlib
   default-language:    Haskell2010
   other-modules: