diff --git a/docs/development/agent-workflow.md b/docs/development/agent-workflow.md
index 2e0add38e..cd315e38f 100644
--- a/docs/development/agent-workflow.md
+++ b/docs/development/agent-workflow.md
@@ -92,7 +92,8 @@ CLAUDE, INSTRUCTIONS, README, CONTRIBUTING and SECURITY, case-insensitively) are
 paths do not receive package exemptions. TypeScript configuration is parsed as JSONC.
 Declared packages also permit safe subpaths; exact aliases stay exact.
 Federated handles in the @user@host form are prose, not imports; trailing closing
-ASCII/Unicode punctuation and possessive apostrophe-s suffixes are ignored, but extra at-signs do not qualify for that exemption.
+ASCII/Unicode punctuation and possessive apostrophe-s suffixes are ignored. Opening
+delimiters separate adjacent prose; nested imports remain checked. Extra at-signs do not qualify for that exemption.
 Exact declared packages remain exempt after version normalization.
 Declared package mentions may include a version (including semver comparators and wildcard ranges) or dist-tag qualifier.
 Qualifier handling includes unscoped names; terminal sentence punctuation is
diff --git a/tools/skills/validate-agent-guidance.mjs b/tools/skills/validate-agent-guidance.mjs
index f1f19cd6b..f09a6a22a 100644
--- a/tools/skills/validate-agent-guidance.mjs
+++ b/tools/skills/validate-agent-guidance.mjs
@@ -228,7 +228,10 @@ export async function validateAgentGuidance({ rootDir }) {
                 if (isPackageMention(token)) continue;
                 if (
                     /^[\w.-]+@(?:[a-z\d](?:[a-z\d-]*[a-z\d])?\.)+[a-z]{2,}$/iu.test(
-                        token.replace(/\p{P}+$/gu, '').replace(/['’]s$/iu, '')
+                        token
+                            .split(/[([{]/u, 1)[0]
+                            .replace(/\p{P}+$/gu, '')
+                            .replace(/['’]s$/iu, '')
                     )
                 )
                     continue;
diff --git a/tools/skills/validate-agent-guidance.test.mjs b/tools/skills/validate-agent-guidance.test.mjs
index 6371ae1e9..321c37bd0 100644
--- a/tools/skills/validate-agent-guidance.test.mjs
+++ b/tools/skills/validate-agent-guidance.test.mjs
@@ -1790,3 +1790,25 @@ for (const suffix of ["'s", '’s']) {
         );
     });
 }
+
+for (const suffix of ['(admin)', '[admin]', '{admin}']) {
+    test(`federated handle permits parenthetical prose: ${suffix}`, async (t) => {
+        assert.deepEqual(
+            await diagnostics(t, {
+                'AGENTS.md': 'Contact @alice@example.social' + suffix,
+            }),
+            []
+        );
+    });
+}
+test('federated handle cannot hide a nested import', async (t) => {
+    assert.ok(
+        (
+            await diagnostics(t, {
+                'CLAUDE.md':
+                    '@AGENTS.md\n\n@alice@example.social(@INSTRUCTIONS)',
+                INSTRUCTIONS: 'Guidance',
+            })
+        ).some((message) => message.includes('additional or inline'))
+    );
+});