diff --git a/hooks/scripts/inject-okr-context.mjs b/hooks/scripts/inject-okr-context.mjs
index 20e2a5e..fadd85e 100644
--- a/hooks/scripts/inject-okr-context.mjs
+++ b/hooks/scripts/inject-okr-context.mjs
@@ -13,6 +13,34 @@ const cwd = process.cwd();
 const projectConfigPath = join(cwd, '.claude', 'okr.local.md');
 const homeConfigPath = join(homedir(), '.claude', 'okr', 'org', 'profil.md');
 
+// Topic guard (UserPromptSubmit): only inject OKR context when the user's
+// prompt is plausibly OKR-related. The stdin read is non-blocking here -- under
+// execFileSync (Claude Code's hook call and the tests) stdin is a closed pipe
+// so EOF is immediate; the isTTY guard avoids blocking in an interactive shell.
+// Default to PASS (inject) on any doubt -- empty/unparseable stdin, missing
+// prompt field, or TTY -- so we never drop a legitimate OKR prompt. Only an
+// explicit non-matching prompt is suppressed. No network.
+let rawPrompt = '';
+try {
+  if (!process.stdin.isTTY) rawPrompt = readFileSync(0, 'utf8');
+} catch {
+  rawPrompt = '';
+}
+if (rawPrompt) {
+  let promptText = null;
+  try {
+    promptText = JSON.parse(rawPrompt).prompt;
+  } catch {
+    promptText = null;
+  }
+  if (typeof promptText === 'string' && promptText.length > 0) {
+    const okrPattern = /\bokr\b|objective|key result|n[oø]kkelresultat|noekkelresultat|\bkr\b|\bm[aå]l\b|\bmaal\b|tildelingsbrev|kaskade|syklus|tertial|kvartal/i;
+    if (!okrPattern.test(promptText)) {
+      process.exit(0);
+    }
+  }
+}
+
 // Hybrid org-profile resolution (most-specific-wins): project-local overrides
 // the machine-global home profile. The home path is the Fase 3 migration target;
 // this read is forward-compatible and stays inert until that file exists.
diff --git a/tests/inject-okr-context.test.mjs b/tests/inject-okr-context.test.mjs
index e05cf39..ce7326b 100644
--- a/tests/inject-okr-context.test.mjs
+++ b/tests/inject-okr-context.test.mjs
@@ -31,15 +31,21 @@ function makeProjectConfig(workDir, navn) {
   writeFileSync(join(p, 'okr.local.md'), `---\nnavn: "${navn}"\n---\n`);
 }
 
-function runHook(cwd, home) {
+function runHook(cwd, home, input = '') {
   // execFileSync returns stdout; the hook always exits 0.
+  // input pipes a UserPromptSubmit payload through stdin so the emne-guard
+  // (topic guard) sees an explicit OKR-relevant prompt instead of suppressing.
   return execFileSync('node', [HOOK], {
     cwd,
     env: { ...process.env, HOME: home },
+    input,
     encoding: 'utf8',
   });
 }
 
+// OKR-relevant prompt slik at emne-guarden injiserer i stedet for aa suppresse.
+const OKR_PROMPT = JSON.stringify({ prompt: 'hjelp meg skrive OKR' });
+
 function withDirs(fn) {
   const home = mkdtempSync(join(tmpdir(), 'okrhome-'));
   const work = mkdtempSync(join(tmpdir(), 'okrwork-'));
@@ -54,7 +60,7 @@ function withDirs(fn) {
 test('kun-hjem: leser org fra hjem-profil, ingen syklus-kontekst', () => {
   withDirs((home, work) => {
     makeHomeProfil(home, 'HjemOrg');
-    const out = runHook(work, home);
+    const out = runHook(work, home, OKR_PROMPT);
     assert.match(out, /HjemOrg/, 'org skal komme fra hjem-profil naar prosjekt-config mangler');
     assert.doesNotMatch(out, /Tilgjengelige kontekstfiler/, 'kun-hjem har ingen prosjekt-lokalt syklus-tre (okrDir er cwd-bundet)');
   });
@@ -64,7 +70,7 @@ test('begge: prosjekt-lokal vinner over hjem (mest-spesifikk-vinner)', () => {
   withDirs((home, work) => {
     makeHomeProfil(home, 'HjemOrg');
     makeProjectConfig(work, 'ProsjektOrg');
-    const out = runHook(work, home);
+    const out = runHook(work, home, OKR_PROMPT);
     assert.match(out, /ProsjektOrg/, 'prosjekt-lokal skal vinne');
     assert.doesNotMatch(out, /HjemOrg/, 'hjem skal ikke leses naar prosjekt-config finnes');
   });
diff --git a/tests/topic-guard.test.mjs b/tests/topic-guard.test.mjs
new file mode 100644
index 0000000..f937126
--- /dev/null
+++ b/tests/topic-guard.test.mjs
@@ -0,0 +1,79 @@
+// topic-guard.test.mjs
+// Tester UserPromptSubmit emne-guard (SC6) i inject-okr-context: kun
+// OKR-relevante prompter injiserer kontekst; en eksplisitt ikke-matchende
+// prompt suppresses; tvil (tomt felt / ingen stdin) -> default-inject.
+// Spawner hooken som subprosess med kontrollert cwd + stdin. Zero npm deps.
+// Moenster: tests/inject-okr-context.test.mjs (begge-casen + input-opsjon).
+
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { execFileSync } from 'node:child_process';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const HOOK = join(
+  dirname(fileURLToPath(import.meta.url)),
+  '..',
+  'hooks',
+  'scripts',
+  'inject-okr-context.mjs',
+);
+
+function makeProjectConfig(workDir, navn) {
+  const p = join(workDir, '.claude');
+  mkdirSync(p, { recursive: true });
+  writeFileSync(join(p, 'okr.local.md'), `---\nnavn: "${navn}"\n---\n`);
+}
+
+function runHook(cwd, input = '') {
+  // execFileSync returnerer stdout; hooken avslutter alltid med exit 0.
+  return execFileSync('node', [HOOK], {
+    cwd,
+    env: { ...process.env },
+    input: input,
+    encoding: 'utf8',
+  });
+}
+
+function withWork(fn) {
+  const work = mkdtempSync(join(tmpdir(), 'okrtopic-'));
+  try {
+    fn(work);
+  } finally {
+    rmSync(work, { recursive: true, force: true });
+  }
+}
+
+test('irrelevant prompt: suppresses injeksjon (tom stdout)', () => {
+  withWork((work) => {
+    makeProjectConfig(work, 'TopicOrg');
+    const out = runHook(work, JSON.stringify({ prompt: 'hva er vaeret i dag' }));
+    assert.equal(out.trim(), '', 'ikke-OKR-prompt skal suppresses selv med gyldig config');
+  });
+});
+
+test('relevant prompt: injiserer OKR-kontekst', () => {
+  withWork((work) => {
+    makeProjectConfig(work, 'TopicOrg');
+    const out = runHook(work, JSON.stringify({ prompt: 'hjelp meg skrive en OKR for neste tertial' }));
+    assert.match(out, /OKR-kontekst/, 'OKR-relevant prompt skal injisere kontekst');
+  });
+});
+
+test('tomt prompt-felt: bevarer inject-default (tvil -> injiser)', () => {
+  withWork((work) => {
+    makeProjectConfig(work, 'TopicOrg');
+    const out = runHook(work, JSON.stringify({ prompt: '' }));
+    assert.match(out, /OKR-kontekst/, 'tomt prompt-felt -> tvil -> injiser');
+  });
+});
+
+test('ingen stdin: bevarer inject-default (regresjonsvakt)', () => {
+  withWork((work) => {
+    makeProjectConfig(work, 'TopicOrg');
+    const out = runHook(work); // input utelatt -> tom stdin
+    assert.match(out, /OKR-kontekst/, 'ingen stdin -> tvil -> injiser');
+  });
+});