diff --git a/CHANGELOG.md b/CHANGELOG.md
index e84f41f8..3b3bf8ea 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Added `attribution` (`service`/`account`) to the contextual-orchestrator AI
+  briefing call so scopeweave's LLM usage is attributed in the
+  orchestrator's cost ledger instead of appearing as unattributed spend.
+  Only orchestrator's own allowed attribution dimensions are ever forwarded
+  (unknown keys and empty/null values are dropped); omitted entirely when
+  the caller passes none, matching pre-existing behavior exactly.
 - Added deterministic PM analysis for requirements/RFI/RFP readiness, WBS
   estimation coverage, dependency risk, and procurement package section checks.
 - Preserved PM-analysis research papers, NASA WBS handbook, BCP 14, and JSON
diff --git a/package.json b/package.json
index 7790e678..a782ce9f 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
     "coverage": "c8 --all --include=app.js --include=cloud-sync.js --include=scripts/ci/static_coverage_evidence.mjs --include=server/app.mjs --include=server/auth.mjs --reporter=json --reporter=json-summary npm run test:coverage",
     "server": "node server/server.mjs",
     "test:api": "node tests/api/auth-secret.test.mjs && node tests/api/smoke.mjs && node tests/api/ratelimit.test.mjs",
-    "test:unit": "node tests/unit/analytics.test.mjs && node tests/unit/cpm.test.mjs && node tests/unit/baseline-compare.test.mjs && node tests/unit/workload.test.mjs && node tests/unit/cost-evm.test.mjs && node tests/unit/msproject.test.mjs && node tests/unit/auth-password.test.mjs && node tests/unit/editor-unsaved.test.mjs && node tests/unit/static-coverage-evidence.test.mjs && node tests/unit/dep-types.test.mjs && node tests/unit/weekly-report.test.mjs && node tests/unit/clearfolio.test.mjs && node tests/unit/sprint-stats.test.mjs && node tests/unit/burndown.test.mjs && node tests/unit/pm-analysis.test.mjs && node tests/unit/cloud-sync-security.test.mjs",
+    "test:unit": "node tests/unit/analytics.test.mjs && node tests/unit/cpm.test.mjs && node tests/unit/baseline-compare.test.mjs && node tests/unit/workload.test.mjs && node tests/unit/cost-evm.test.mjs && node tests/unit/msproject.test.mjs && node tests/unit/auth-password.test.mjs && node tests/unit/editor-unsaved.test.mjs && node tests/unit/static-coverage-evidence.test.mjs && node tests/unit/dep-types.test.mjs && node tests/unit/weekly-report.test.mjs && node tests/unit/clearfolio.test.mjs && node tests/unit/sprint-stats.test.mjs && node tests/unit/burndown.test.mjs && node tests/unit/pm-analysis.test.mjs && node tests/unit/cloud-sync-security.test.mjs && node tests/unit/orchestrator.test.mjs",
     "test:coverage": "node tests/unit/msproject.test.mjs && node tests/unit/auth-password.test.mjs && node tests/unit/editor-unsaved.test.mjs && node tests/unit/static-coverage-evidence.test.mjs && npm run test:api",
     "test:e2e": "playwright test",
     "test:e2e:headed": "playwright test --headed",
diff --git a/server/app.mjs b/server/app.mjs
index 13d95e5d..0608459a 100644
--- a/server/app.mjs
+++ b/server/app.mjs
@@ -981,7 +981,7 @@ app.post('/api/projects/:id/ai/brief', requireAuth, async (c) => {
     const analysis = await orchestratorChat([
       { role: 'system', content: '너는 공정관리(schedule control) 전문가다. 주어진 프로젝트 지표를 근거로 한국어 경영진 브리핑을 작성하라: ①일정 상태 한 줄 판정 ②핵심 리스크 2~3개(근거 지표 인용) ③실행 권고 2~3개. 지표에 없는 사실은 만들지 마라.' },
       { role: 'user', content: context },
-    ]);
+    ], { service: 'scopeweave', account: p.org_id });
     logAudit(p.org_id, uid, 'ai.brief', 'project', p.id, { tasks: tasks.length });
     return c.json({ analysis });
   } catch (e) {
diff --git a/server/orchestrator.mjs b/server/orchestrator.mjs
index 1205ebe7..cf543b2c 100644
--- a/server/orchestrator.mjs
+++ b/server/orchestrator.mjs
@@ -6,7 +6,24 @@ const OC_TOKEN = process.env.ORCHESTRATOR_TOKEN || '';
 
 export const orchestratorMock = !OC_URL;
 
-export async function chat(messages) {
+// orchestrator는 알 수 없는 필드를 거부(strict validation)하지만 attribution은
+// 명시적으로 허용된 필드다(ATTRIBUTION_DIMENSIONS: account/service/upstream_api/
+// model_name/team/group/company, + provider 별칭). 값을 넘기지 않으면 해당 호출은
+// orchestrator 비용 원장에서 "unattributed"로 집계된다.
+const ATTRIBUTION_DIMENSIONS = new Set([
+  'account', 'service', 'upstream_api', 'model_name', 'team', 'group', 'company', 'provider',
+]);
+
+function sanitizeAttribution(attribution) {
+  if (!attribution || typeof attribution !== 'object') return undefined;
+  const entries = Object.entries(attribution).filter(
+    ([key, value]) => ATTRIBUTION_DIMENSIONS.has(key) && value != null && String(value).length > 0,
+  );
+  if (entries.length === 0) return undefined;
+  return Object.fromEntries(entries.map(([key, value]) => [key, String(value)]));
+}
+
+export async function chat(messages, attribution) {
   if (orchestratorMock) {
     const user = messages.filter((m) => m.role === 'user').map((m) => m.content).join('\n');
     return `[mock-orchestrator] 분석 요약: ${user.slice(0, 120)}…에 대한 모의 응답입니다. `
@@ -15,14 +32,18 @@ export async function chat(messages) {
   const ctrl = new AbortController();
   const to = setTimeout(() => ctrl.abort(), 60000);
   try {
+    const cleanAttribution = sanitizeAttribution(attribution);
     const res = await fetch(`${OC_URL}/v1/chat/completions`, {
       method: 'POST',
       headers: {
         'content-type': 'application/json',
         ...(OC_TOKEN ? { authorization: `Bearer ${OC_TOKEN}` } : {}),
       },
-      // orchestrator는 알 수 없는 필드를 거부(strict validation) — model+messages만 전송.
-      body: JSON.stringify({ model: 'contextual-orchestrator', messages }),
+      body: JSON.stringify({
+        model: 'contextual-orchestrator',
+        messages,
+        ...(cleanAttribution ? { attribution: cleanAttribution } : {}),
+      }),
       signal: ctrl.signal,
     });
     const data = await res.json().catch(() => ({}));
diff --git a/tests/unit/orchestrator.test.mjs b/tests/unit/orchestrator.test.mjs
new file mode 100644
index 00000000..e4b545f9
--- /dev/null
+++ b/tests/unit/orchestrator.test.mjs
@@ -0,0 +1,64 @@
+// contextual-orchestrator client: attribution forwarding + sanitization.
+// Run: node tests/unit/orchestrator.test.mjs
+import assert from 'node:assert/strict';
+import { spawnSync } from 'node:child_process';
+
+// orchestrator.mjs reads ORCHESTRATOR_URL at module load time, so the
+// non-mock path can only be exercised in a fresh process with the env var
+// already set — same pattern as tests/api/auth-secret.test.mjs. Stubs
+// global fetch and prints the captured request body as JSON for this
+// process to assert on.
+function chatRequestBody(attribution) {
+  const script = `
+    globalThis.fetch = async (url, opts) => {
+      console.log(JSON.stringify({ url, body: JSON.parse(opts.body) }));
+      return { ok: true, json: async () => ({ choices: [{ message: { content: 'ok' } }] }) };
+    };
+    const { chat } = await import('./server/orchestrator.mjs');
+    await chat([{ role: 'user', content: 'hi' }], ${JSON.stringify(attribution)});
+  `;
+  const env = { ...process.env, ORCHESTRATOR_URL: 'http://orchestrator.test', ORCHESTRATOR_TOKEN: 'tok' };
+  const result = spawnSync(
+    process.execPath,
+    ['--input-type=module', '--eval', script],
+    { cwd: process.cwd(), env, encoding: 'utf8' },
+  );
+  assert.equal(result.status, 0, `chat() failed: ${result.stderr}`);
+  return JSON.parse(result.stdout.trim());
+}
+
+// Known dimensions are forwarded, coerced to strings, exactly as given.
+{
+  const { url, body } = chatRequestBody({ service: 'scopeweave', account: 'org-123' });
+  assert.equal(url, 'http://orchestrator.test/v1/chat/completions');
+  assert.equal(body.model, 'contextual-orchestrator');
+  assert.deepEqual(body.attribution, { service: 'scopeweave', account: 'org-123' });
+}
+
+// Unknown keys and null/empty values are dropped, never forwarded verbatim.
+{
+  const { body } = chatRequestBody({
+    service: 'scopeweave',
+    not_a_real_dimension: 'x',
+    account: '',
+    team: null,
+  });
+  assert.deepEqual(body.attribution, { service: 'scopeweave' });
+}
+
+// If nothing valid remains after sanitizing, the field is omitted entirely
+// rather than sent as an empty object — matches orchestrator's contract of
+// treating a present-but-empty attribution differently from an absent one.
+{
+  const { body } = chatRequestBody({ not_a_real_dimension: 'x' });
+  assert.equal('attribution' in body, false);
+}
+
+// No attribution argument at all: unchanged pre-existing behavior.
+{
+  const { body } = chatRequestBody(undefined);
+  assert.equal('attribution' in body, false);
+  assert.deepEqual(Object.keys(body).sort(), ['messages', 'model']);
+}
+
+console.log('✓ orchestrator attribution tests passed');