diff --git a/packages/agents/package.json b/packages/agents/package.json
index 49c9c9c2..09ede584 100644
--- a/packages/agents/package.json
+++ b/packages/agents/package.json
@@ -32,8 +32,7 @@
     "dist"
   ],
   "scripts": {
-    "build": "nmr compile && tsx scripts/bundle-skill-helpers.ts && tsx scripts/copy-content.ts",
-    "build:post": "rdy compile",
+    "build:post": "tsx scripts/bundle-skill-helpers.ts && tsx scripts/copy-content.ts && rdy compile",
     "build:pre": "rdy verify",
     "prepublishOnly": "nmr build",
     "test:post": "pnpm run test:sh && pnpm run test:smoke",
diff --git a/packages/kb/package.json b/packages/kb/package.json
index 8f1df5ae..d3dd6c21 100644
--- a/packages/kb/package.json
+++ b/packages/kb/package.json
@@ -96,7 +96,6 @@
     "dist"
   ],
   "scripts": {
-    "build": "nmr compile",
     "prepublishOnly": "nmr build"
   },
   "dependencies": {
diff --git a/packages/lifecycle/package.json b/packages/lifecycle/package.json
index 664e218f..9e032bf6 100644
--- a/packages/lifecycle/package.json
+++ b/packages/lifecycle/package.json
@@ -32,7 +32,6 @@
     "dist"
   ],
   "scripts": {
-    "build": "nmr compile",
     "prepublishOnly": "nmr build"
   },
   "devDependencies": {
diff --git a/packages/mcp/package.json b/packages/mcp/package.json
index 214b4b6e..f92c7388 100644
--- a/packages/mcp/package.json
+++ b/packages/mcp/package.json
@@ -11,9 +11,6 @@
     "bin",
     "dist"
   ],
-  "scripts": {
-    "build": "nmr compile"
-  },
   "dependencies": {
     "@modelcontextprotocol/sdk": "1.30.0",
     "@williamthorsen/toolbelt.errors": "catalog:",
diff --git a/packages/run-core/package.json b/packages/run-core/package.json
index 0998a94f..d57bcde0 100644
--- a/packages/run-core/package.json
+++ b/packages/run-core/package.json
@@ -30,9 +30,6 @@
   "files": [
     "dist"
   ],
-  "scripts": {
-    "build": "nmr compile"
-  },
   "dependencies": {
     "@williamthorsen/toolbelt.errors": "catalog:",
     "yaml": "2.9.0",
diff --git a/scripts/__tests__/package-contents.tool.test.ts b/scripts/__tests__/package-contents.tool.test.ts
index 5da1910d..e5d762c9 100644
--- a/scripts/__tests__/package-contents.tool.test.ts
+++ b/scripts/__tests__/package-contents.tool.test.ts
@@ -1,12 +1,10 @@
 import { execFileSync } from 'node:child_process';
-import { readdirSync, readFileSync } from 'node:fs';
+import { readFileSync } from 'node:fs';
 import path from 'node:path';
 
+import { findMonorepoRoot, getWorkspacePackageDirs } from '@williamthorsen/nmr/workspace';
 import { describe, expect, it } from 'vitest';
 
-/** Absolute path to the workspace directory holding every package. */
-const packagesDir = path.resolve(import.meta.dirname, '..', '..', 'packages');
-
 /**
  * Paths a named package must ship beyond the invariants every publishable package satisfies. A value matches by
  * prefix, so an exact file path names itself and a directory names everything under it.
@@ -58,21 +56,18 @@ interface PublishablePackage {
  * covered without editing this suite.
  */
 function findPublishablePackages(): ReadonlyArray<PublishablePackage> {
-  const packages = readdirSync(packagesDir, { withFileTypes: true })
-    .filter((entry) => entry.isDirectory())
-    .flatMap((entry) => {
-      const dir = path.join(packagesDir, entry.name);
-      const manifest: unknown = JSON.parse(readFileSync(path.join(dir, 'package.json'), 'utf8'));
-      if (typeof manifest !== 'object' || manifest === null) {
-        return [];
-      }
-      const isPrivate = 'private' in manifest && manifest.private === true;
-      const name = 'name' in manifest && typeof manifest.name === 'string' ? manifest.name : undefined;
-      if (isPrivate || name === undefined) {
-        return [];
-      }
-      return [{ bins: readBinPaths(manifest), dir, name }];
-    });
+  const packages = getWorkspacePackageDirs(findMonorepoRoot(import.meta.dirname)).flatMap((dir) => {
+    const manifest: unknown = JSON.parse(readFileSync(path.join(dir, 'package.json'), 'utf8'));
+    if (typeof manifest !== 'object' || manifest === null) {
+      return [];
+    }
+    const isPrivate = 'private' in manifest && manifest.private === true;
+    const name = 'name' in manifest && typeof manifest.name === 'string' ? manifest.name : undefined;
+    if (isPrivate || name === undefined) {
+      return [];
+    }
+    return [{ bins: readBinPaths(manifest), dir, name }];
+  });
   return packages.toSorted((a, b) => a.name.localeCompare(b.name));
 }
 
diff --git a/scripts/__tests__/package-scripts.unit.test.ts b/scripts/__tests__/package-scripts.unit.test.ts
new file mode 100644
index 00000000..9548c1c6
--- /dev/null
+++ b/scripts/__tests__/package-scripts.unit.test.ts
@@ -0,0 +1,138 @@
+import { readFileSync } from 'node:fs';
+import path from 'node:path';
+
+import { findMonorepoRoot, getWorkspacePackageDirs } from '@williamthorsen/nmr/workspace';
+import { describe, expect, it } from 'vitest';
+
+/**
+ * Script names npm and pnpm invoke on their own schedule, which nmr never resolves as a command. A name nmr does
+ * carry — `test` among them — stays out of this set, so an nmr call added there is still reported.
+ */
+const lifecycleScriptNames: ReadonlySet<string> = new Set([
+  'postinstall',
+  'postpack',
+  'preinstall',
+  'prepack',
+  'prepare',
+  'prepublish',
+  'prepublishOnly',
+]);
+
+/**
+ * Script names the root manifest may reach nmr from. nmr resolves that manifest as a tier-3 override the way it
+ * resolves a package's, so the rest of it is guarded too. `bootstrap` builds and deploys from a fresh checkout,
+ * where the bare `nmr` binary is not yet on the path, and so reaches nmr through pnpm by design.
+ */
+const rootExemptScriptNames: ReadonlySet<string> = new Set([...lifecycleScriptNames, 'bootstrap']);
+
+/**
+ * Matches a command reaching `nmr` as a whole token, which covers any runner that fronts it — `npx nmr`,
+ * `pnpm exec nmr`, `pnpm --filter x exec nmr`. nmr's own warning inspects only a command's first token, so it
+ * backstops none of those forms. The lookahead spares the leaf bins (`nmr-compile`, `nmr-fmt`) and a path segment
+ * such as `nmr/bin`, none of which start a nested run.
+ */
+const shelledNmrPattern = /(?:^|[\s;&|])nmr(?![\w\-/])/;
+
+/** One manifest the guard reads, with the script names it may reach nmr from. */
+interface GuardedManifest {
+  readonly exemptNames: ReadonlySet<string>;
+  readonly manifestPath: string;
+  readonly scripts: Readonly<Record<string, string>>;
+}
+
+describe.each(findGuardedManifests())('$manifestPath scripts', ({ exemptNames, manifestPath, scripts }) => {
+  it('reach nmr through no shell', () => {
+    // A shelled step puts the nested run's output on the channels a tool's takes, so a quiet failure surrenders the
+    // whole subtree instead of the failing step.
+    expect(
+      findShelledNmrScripts(scripts, exemptNames),
+      `${manifestPath} invokes nmr through a shell. Delete the override where it restates nmr's own default, or move the steps into a hook such as \`build:post\`.`,
+    ).toEqual([]);
+  });
+});
+
+describe('findShelledNmrScripts', () => {
+  it.each([
+    ['a bare invocation', 'nmr compile'],
+    ['a chained invocation', 'tsx scripts/build.ts && nmr compile'],
+    ['an unspaced operator', 'tsx scripts/build.ts&&nmr compile'],
+    ['a pnpm exec runner', 'pnpm exec nmr build'],
+    ['a filtered pnpm runner', 'pnpm --filter codeassembly exec nmr build'],
+    ['a recursive pnpm runner', 'pnpm --recursive exec nmr build'],
+    ['an npx runner', 'npx nmr build'],
+  ])('reports %s', (_label, command) => {
+    expect(findShelledNmrScripts({ build: command }, lifecycleScriptNames)).toEqual(['build']);
+  });
+
+  it.each([
+    ['a leaf bin', 'nmr-compile'],
+    ['a flagged leaf bin', 'nmr-fmt --check'],
+    ['a path segment', 'node node_modules/@williamthorsen/nmr/bin/cli.js'],
+    ['an unrelated command', 'tsx scripts/build.ts && rdy compile'],
+  ])('passes over %s', (_label, command) => {
+    expect(findShelledNmrScripts({ build: command }, lifecycleScriptNames)).toEqual([]);
+  });
+
+  it('passes over an exempt script name', () => {
+    expect(findShelledNmrScripts({ prepublishOnly: 'nmr build' }, lifecycleScriptNames)).toEqual([]);
+  });
+
+  it('reports every offending name in sorted order', () => {
+    const scripts = { build: 'nmr compile', check: 'npx nmr lint', fmt: 'nmr-fmt --write' };
+    expect(findShelledNmrScripts(scripts, lifecycleScriptNames)).toEqual(['build', 'check']);
+  });
+});
+
+// region | Helpers
+
+/** Lists the manifests the guard reads: the monorepo root's, then every workspace package's. */
+function findGuardedManifests(): ReadonlyArray<GuardedManifest> {
+  const monorepoRoot = findMonorepoRoot(import.meta.dirname);
+  const packageManifests = getWorkspacePackageDirs(monorepoRoot).map((dir) => ({
+    exemptNames: lifecycleScriptNames,
+    manifestPath: path.relative(monorepoRoot, path.join(dir, 'package.json')),
+    scripts: readScripts(path.join(dir, 'package.json')),
+  }));
+  return [
+    {
+      exemptNames: rootExemptScriptNames,
+      manifestPath: 'package.json',
+      scripts: readScripts(path.join(monorepoRoot, 'package.json')),
+    },
+    ...packageManifests,
+  ];
+}
+
+/** Lists the script names whose values reach nmr through a shell, passing over the exempt names. */
+function findShelledNmrScripts(
+  scripts: Readonly<Record<string, string>>,
+  exemptNames: ReadonlySet<string>,
+): ReadonlyArray<string> {
+  return Object.entries(scripts)
+    .filter(([name, value]) => !exemptNames.has(name) && shelledNmrPattern.test(value))
+    .map(([name]) => name)
+    .toSorted();
+}
+
+/** Reads a manifest's `scripts` field, keeping the string values nmr can resolve as a command. */
+function readScripts(manifestPath: string): Readonly<Record<string, string>> {
+  const manifest: unknown = JSON.parse(readFileSync(manifestPath, 'utf8'));
+  if (typeof manifest !== 'object' || manifest === null || !('scripts' in manifest)) {
+    return {};
+  }
+  const { scripts } = manifest;
+  if (typeof scripts !== 'object' || scripts === null) {
+    return {};
+  }
+  // The annotation is what keeps `Object.entries` from widening each value to `any` and defeating the check below.
+  const entries: ReadonlyArray<readonly [string, unknown]> = Object.entries(scripts);
+  const result: Record<string, string> = {};
+  for (const [name, value] of entries) {
+    if (typeof value === 'string') {
+      result[name] = value;
+    }
+  }
+  return result;
+}
+
+// endregion | Helpers