diff --git a/README.md b/README.md
index e69ad53..a6f682b 100644
--- a/README.md
+++ b/README.md
@@ -164,7 +164,10 @@ export MESH_LAB_ROUTE_PROXY=<somewhere>/route-proxy
 
 `MESH_LAB_HOST_BINARY` and `MESH_LAB_MODULES` do double duty: the repository each sits in is what
 `suite` rebuilds and what the receipt claims. Point the run at a repository and it is built and
-claimed; leave it out and it is neither.
+claimed; leave it out and it is neither. `MESH_LAB_CATALOG` is claimed without being built: a bed
+installs a catalogue module by reading its manifest from that checkout when it runs, so the
+receipt names the catalogue's commit too, and a run taken before a manifest changed says so
+(novox/hq 04-ISSUES/073).
 
 Check before running a long suite — it says which of these are missing rather than skipping
 quietly:
diff --git a/src/repos.ts b/src/repos.ts
index c0330e0..4e9ce50 100644
--- a/src/repos.ts
+++ b/src/repos.ts
@@ -10,7 +10,7 @@
  * pointed at is neither built nor claimed.
  */
 
-import { dirname } from "node:path";
+import { basename, dirname } from "node:path";
 
 export interface Repositories {
   /** Absolute path to the repository root, by name. */
@@ -24,5 +24,16 @@ export function repositories(env: NodeJS.ProcessEnv = process.env): Repositories
   if (host) found["mesh-host"] = dirname(host);
   const modules = env["MESH_LAB_MODULES"];
   if (modules) found["mesh-controller"] = dirname(dirname(modules));
+  // The catalogue is read, not built: a bed installs a module by reading its manifest from this
+  // checkout at run time (novox/hq 04-ISSUES/073). A receipt that did not name the catalogue's
+  // commit could not say whether a catalogue change had been proven — the beds used to carry
+  // their own copies of the manifests, and then it could not.
+  const catalogue = env["MESH_LAB_CATALOG"];
+  if (catalogue) found["mesh-catalog"] = catalogueRoot(catalogue);
   return found;
 }
+
+/** MESH_LAB_CATALOG is accepted under either spelling — the checkout, or its `modules` directory. */
+export function catalogueRoot(catalogue: string): string {
+  return basename(catalogue) === "modules" ? dirname(catalogue) : catalogue;
+}
diff --git a/test/rebuild.test.ts b/test/rebuild.test.ts
index 32af5f5..8d7855c 100644
--- a/test/rebuild.test.ts
+++ b/test/rebuild.test.ts
@@ -104,12 +104,28 @@ test("every repository the receipt claims was built by the run", () => {
     MESH_LAB_HOST_BINARY: "/repo/host/mesh-host",
     MESH_LAB_MODULES: "/repo/control/examples/modules",
     MESH_LAB_BUILDER: "/repo/control/build/mesh-builder",
+    MESH_LAB_CATALOG: "/repo/catalog/modules",
   };
   const built = new Set(planned(env).map((b) => b.in));
   for (const [name, directory] of Object.entries(repositories(env))) {
     // mesh-lab is the exception, and it is not an omission: it is TypeScript run from source, so
     // the code under test *is* the code running. There is nothing to build and nothing to go stale.
     if (name === "mesh-lab") continue;
+    // mesh-catalog is the other exception, for the other reason: what a bed takes from it is a
+    // manifest, read from disk when the bed runs. There is nothing built from it that could go
+    // stale — and claiming it is the whole point, since a bed that carried its own copy of the
+    // manifest was proving the copy (novox/hq 04-ISSUES/073).
+    if (name === "mesh-catalog") continue;
     assert.ok(built.has(directory), `${name} (${directory}) is claimed but never built`);
   }
 });
+
+// The catalogue is claimed by the receipt, under either spelling the beds accept.
+//
+// A bed reads the manifest it installs from the catalogue checkout (novox/hq 04-ISSUES/073), so a
+// receipt that names no catalogue commit cannot say whether a change there was ever proven.
+test("the receipt claims the catalogue the beds read, however it was named", () => {
+  assert.equal(repositories({ MESH_LAB_CATALOG: "/repo/catalog/modules" })["mesh-catalog"], "/repo/catalog");
+  assert.equal(repositories({ MESH_LAB_CATALOG: "/repo/catalog" })["mesh-catalog"], "/repo/catalog");
+  assert.equal(repositories({})["mesh-catalog"], undefined);
+});