diff --git a/src/audit.ts b/src/audit.ts
index 05c3472..9801781 100644
--- a/src/audit.ts
+++ b/src/audit.ts
@@ -75,6 +75,10 @@ export function audit(
     tsMs: ts,
     requestId: claims.requestId,
     wallet: claims.wallet,
+    // Which agent credential was used. Without it every agent action in the
+    // log is indistinguishable from the owner's own, so a leaked credential
+    // leaves no trace of WHICH agent it impersonated.
+    agent: claims.agent ?? null,
     convId: claims.convId,
     role: claims.role,
     tool: record.tool,
diff --git a/src/auth/jwt.ts b/src/auth/jwt.ts
index bd21255..50e7d7f 100644
--- a/src/auth/jwt.ts
+++ b/src/auth/jwt.ts
@@ -20,6 +20,16 @@ import { config } from "../config.js";
 
 export type TokenClaims = {
   wallet: string;
+  /**
+   * WHO acted, when the caller is an agent rather than a person.
+   *
+   * `wallet` is the BOARD's owner: for an invited agent it is the human's
+   * wallet, so it cannot tell the agent's actions apart from the human's, and
+   * a leaked agent credential reads as the owner. Optional because tokens
+   * minted before this claim existed must keep verifying — the checks below
+   * are by type and ignore extras.
+   */
+  agent?: string;
   convId: string;
   role: "user" | "admin";
   requestId: string;
@@ -109,6 +119,7 @@ export function verifyToken(token: string): VerifyResult {
     typeof payload.role !== "string" ||
     !["user", "admin"].includes(payload.role) ||
     typeof payload.requestId !== "string" ||
+    (payload.agent !== undefined && typeof payload.agent !== "string") ||
     typeof payload.iat !== "number" ||
     typeof payload.exp !== "number"
   ) {
@@ -133,6 +144,10 @@ export function verifyToken(token: string): VerifyResult {
       convId: payload.convId,
       role: payload.role as "user" | "admin",
       requestId: payload.requestId,
+      // Absent on tokens minted before the claim existed.
+      ...(typeof payload.agent === "string" && payload.agent
+        ? { agent: payload.agent }
+        : {}),
       iat: payload.iat,
       exp: payload.exp,
     },
diff --git a/tests/agentClaim.test.ts b/tests/agentClaim.test.ts
new file mode 100644
index 0000000..d60d05d
--- /dev/null
+++ b/tests/agentClaim.test.ts
@@ -0,0 +1,59 @@
+import { describe, expect, it } from "vitest";
+
+// Set required env BEFORE importing the modules so config validation passes.
+process.env.FIREBASE_PROJECT_ID = "test-project";
+process.env.FIREBASE_CLIENT_EMAIL = "test@example.com";
+process.env.FIREBASE_PRIVATE_KEY = "-----BEGIN PRIVATE KEY-----\\nfake\\n-----END PRIVATE KEY-----";
+process.env.JWT_SHARED_SECRET = "a".repeat(40);
+
+const { signToken, verifyToken } = await import("../src/auth/jwt.js");
+
+const WALLET = "0xc2564e41b7f5cb66d2d99466450cfebce9e8228f";
+
+/**
+ * `wallet` identifies the BOARD, not the caller. For an invited agent it is the
+ * human owner's wallet, so without a separate claim every agent action is
+ * indistinguishable from the owner's own — and a leaked agent credential
+ * leaves no trace of which agent it impersonated.
+ */
+describe("agent claim", () => {
+  it("round-trips the acting agent", () => {
+    const token = signToken({
+      wallet: WALLET,
+      convId: "agent:Athena",
+      role: "user",
+      requestId: "req-1",
+      agent: "Athena",
+    });
+    const result = verifyToken(token);
+    expect(result.ok).toBe(true);
+    if (result.ok) expect(result.claims.agent).toBe("Athena");
+  });
+
+  it("still accepts tokens minted before the claim existed", () => {
+    const token = signToken({
+      wallet: WALLET,
+      convId: `assistant-${WALLET}`,
+      role: "user",
+      requestId: "req-2",
+    });
+    const result = verifyToken(token);
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.claims.agent).toBeUndefined();
+      expect(result.claims.wallet).toBe(WALLET);
+    }
+  });
+
+  it("rejects a non-string agent instead of silently dropping it", () => {
+    const token = signToken({
+      wallet: WALLET,
+      convId: "agent:Athena",
+      role: "user",
+      requestId: "req-3",
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      agent: 42 as any,
+    });
+    expect(verifyToken(token).ok).toBe(false);
+  });
+});