diff --git a/packages/core/src/authority.js b/packages/core/src/authority.js
new file mode 100644
index 0000000..7694924
--- /dev/null
+++ b/packages/core/src/authority.js
@@ -0,0 +1,278 @@
+// Authority handling for Nostr Governance
+//
+// This module handles role resolution, capability checking, and authority
+// validation for the governance system.
+
+/**
+ * @typedef {Object} RoleDefinition
+ * @property {string} name - Role name
+ * @property {string[]} capabilities - Array of capability names this role has
+ */
+
+/**
+ * @typedef {Object} Actor
+ * @property {string} pubkey - 64-character hex pubkey of the actor
+ * @property {string[]} roles - Array of role names assigned to this actor
+ */
+
+/**
+ * @typedef {Object} AuthorityState
+ * @property {Record<string, RoleDefinition>} roles - Map of role names to definitions
+ * @property {Record<string, Actor>} actors - Map of pubkeys to actors
+ */
+
+/**
+ * Built-in role definitions
+ * @type {Record<string, RoleDefinition>}
+ */
+export const BUILTIN_ROLES = {
+  "root": {
+    name: "root",
+    capabilities: [
+      "manage-roles",
+      "manage-capabilities",
+      "manage-actors",
+      "manage-policies",
+      "manage-admin-lists",
+      "manage-trust-graph",
+      "manage-overrides",
+      "view-reports",
+      "view-trust-graph",
+      "view-admin-lists",
+      "view-policies"
+    ]
+  },
+  "administrator": {
+    name: "administrator",
+    capabilities: [
+      "manage-admin-lists",
+      "manage-trust-graph",
+      "view-reports",
+      "view-trust-graph",
+      "view-admin-lists"
+    ]
+  },
+  "moderator": {
+    name: "moderator",
+    capabilities: [
+      "submit-reports",
+      "submit-trust-endorsements",
+      "view-reports"
+    ]
+  },
+  "trusted-user": {
+    name: "trusted-user",
+    capabilities: [
+      "submit-reports",
+      "view-reports"
+    ]
+  },
+  "user": {
+    name: "user",
+    capabilities: [
+      "submit-reports"
+    ]
+  }
+};
+
+/**
+ * Get capabilities for a role
+ * @param {string} roleName
+ * @param {AuthorityState} [authorityState]
+ * @returns {string[]}
+ */
+export function getRoleCapabilities(roleName, authorityState) {
+  // Check custom roles first
+  if (authorityState && authorityState.roles[roleName]) {
+    return authorityState.roles[roleName].capabilities;
+  }
+  
+  // Check built-in roles
+  if (BUILTIN_ROLES[roleName]) {
+    return BUILTIN_ROLES[roleName].capabilities;
+  }
+  
+  // Unknown role has no capabilities
+  return [];
+}
+
+/**
+ * Check if an actor has a specific role
+ * @param {string} pubkey - 64-character hex pubkey
+ * @param {string} roleName
+ * @param {AuthorityState} [authorityState]
+ * @returns {boolean}
+ */
+export function hasRole(pubkey, roleName, authorityState) {
+  // Normalize pubkey
+  const normalizedPubkey = pubkey.toLowerCase();
+  
+  // Check custom actors first
+  if (authorityState && authorityState.actors[normalizedPubkey]) {
+    return authorityState.actors[normalizedPubkey].roles.includes(roleName);
+  }
+  
+  // No actor found means no roles
+  return false;
+}
+
+/**
+ * Get all roles for an actor
+ * @param {string} pubkey - 64-character hex pubkey
+ * @param {AuthorityState} [authorityState]
+ * @returns {string[]}
+ */
+export function getActorRoles(pubkey, authorityState) {
+  // Normalize pubkey
+  const normalizedPubkey = pubkey.toLowerCase();
+  
+  // Check custom actors first
+  if (authorityState && authorityState.actors[normalizedPubkey]) {
+    return authorityState.actors[normalizedPubkey].roles;
+  }
+  
+  // No actor found means no roles
+  return [];
+}
+
+/**
+ * Check if an actor has a specific capability
+ * @param {string} pubkey - 64-character hex pubkey
+ * @param {string} capability
+ * @param {AuthorityState} [authorityState]
+ * @returns {boolean}
+ */
+export function hasCapability(pubkey, capability, authorityState) {
+  // Get all roles for the actor
+  const roles = getActorRoles(pubkey, authorityState);
+  
+  // Check if any role has the capability
+  for (const role of roles) {
+    const capabilities = getRoleCapabilities(role, authorityState);
+    if (capabilities.includes(capability)) {
+      return true;
+    }
+  }
+  
+  return false;
+}
+
+/**
+ * Get all capabilities for an actor
+ * @param {string} pubkey - 64-character hex pubkey
+ * @param {AuthorityState} [authorityState]
+ * @returns {string[]}
+ */
+export function getActorCapabilities(pubkey, authorityState) {
+  // Get all roles for the actor
+  const roles = getActorRoles(pubkey, authorityState);
+  
+  // Collect all capabilities from all roles
+  const capabilities = new Set();
+  for (const role of roles) {
+    const roleCapabilities = getRoleCapabilities(role, authorityState);
+    for (const capability of roleCapabilities) {
+      capabilities.add(capability);
+    }
+  }
+  
+  return Array.from(capabilities);
+}
+
+/**
+ * Create a new role definition
+ * @param {string} name - Role name
+ * @param {string[]} capabilities - Array of capability names
+ * @returns {RoleDefinition}
+ */
+export function createRoleDefinition(name, capabilities) {
+  // Validate input
+  if (typeof name !== "string" || !name.trim()) {
+    throw new Error("Role name must be a non-empty string");
+  }
+  
+  if (!Array.isArray(capabilities)) {
+    throw new Error("Capabilities must be an array");
+  }
+  
+  // Validate each capability
+  for (const capability of capabilities) {
+    if (typeof capability !== "string" || !capability.trim()) {
+      throw new Error("All capabilities must be non-empty strings");
+    }
+  }
+  
+  return {
+    name: name.trim(),
+    capabilities: capabilities.map(c => c.trim())
+  };
+}
+
+/**
+ * Create a new actor
+ * @param {string} pubkey - 64-character hex pubkey
+ * @param {string[]} roles - Array of role names
+ * @returns {Actor}
+ */
+export function createActor(pubkey, roles) {
+  // Validate pubkey
+  if (typeof pubkey !== "string" || !/^[0-9a-f]{64}$/i.test(pubkey)) {
+    throw new Error("Pubkey must be a 64-character hex string");
+  }
+  
+  // Validate roles
+  if (!Array.isArray(roles)) {
+    throw new Error("Roles must be an array");
+  }
+  
+  // Validate each role
+  for (const role of roles) {
+    if (typeof role !== "string" || !role.trim()) {
+      throw new Error("All roles must be non-empty strings");
+    }
+  }
+  
+  return {
+    pubkey: pubkey.toLowerCase(),
+    roles: roles.map(r => r.trim())
+  };
+}
+
+/**
+ * Create a new authority state
+ * @param {Record<string, RoleDefinition>} [roles]
+ * @param {Record<string, Actor>} [actors]
+ * @returns {AuthorityState}
+ */
+export function createAuthorityState(roles = {}, actors = {}) {
+  // Validate roles
+  for (const [name, role] of Object.entries(roles)) {
+    if (typeof name !== "string" || !name.trim()) {
+      throw new Error("Role names must be non-empty strings");
+    }
+    if (!role || typeof role !== "object") {
+      throw new Error("Role definitions must be objects");
+    }
+    if (role.name !== name) {
+      throw new Error(`Role name mismatch: ${name} !== ${role.name}`);
+    }
+  }
+  
+  // Validate actors
+  for (const [pubkey, actor] of Object.entries(actors)) {
+    if (typeof pubkey !== "string" || !/^[0-9a-f]{64}$/i.test(pubkey)) {
+      throw new Error("Actor pubkeys must be 64-character hex strings");
+    }
+    if (!actor || typeof actor !== "object") {
+      throw new Error("Actors must be objects");
+    }
+    if (actor.pubkey !== pubkey.toLowerCase()) {
+      throw new Error(`Actor pubkey mismatch: ${pubkey} !== ${actor.pubkey}`);
+    }
+  }
+  
+  return {
+    roles,
+    actors
+  };
+}
\ No newline at end of file
diff --git a/packages/core/test/authority.test.js b/packages/core/test/authority.test.js
new file mode 100644
index 0000000..f091b17
--- /dev/null
+++ b/packages/core/test/authority.test.js
@@ -0,0 +1,392 @@
+import { describe, it, expect } from "vitest";
+import {
+  BUILTIN_ROLES,
+  getRoleCapabilities,
+  hasRole,
+  getActorRoles,
+  hasCapability,
+  getActorCapabilities,
+  createRoleDefinition,
+  createActor,
+  createAuthorityState
+} from "../src/authority.js";
+
+describe("authority", () => {
+  describe("BUILTIN_ROLES", () => {
+    it("should define built-in roles with capabilities", () => {
+      expect(BUILTIN_ROLES).toHaveProperty("root");
+      expect(BUILTIN_ROLES).toHaveProperty("administrator");
+      expect(BUILTIN_ROLES).toHaveProperty("moderator");
+      expect(BUILTIN_ROLES).toHaveProperty("trusted-user");
+      expect(BUILTIN_ROLES).toHaveProperty("user");
+      
+      // Check that each role has a name and capabilities
+      for (const [name, role] of Object.entries(BUILTIN_ROLES)) {
+        expect(role.name).toBe(name);
+        expect(Array.isArray(role.capabilities)).toBe(true);
+        expect(role.capabilities.length).toBeGreaterThan(0);
+      }
+    });
+  });
+
+  describe("getRoleCapabilities", () => {
+    it("should return capabilities for built-in roles", () => {
+      const capabilities = getRoleCapabilities("root");
+      expect(capabilities).toEqual(BUILTIN_ROLES.root.capabilities);
+    });
+
+    it("should return capabilities for custom roles", () => {
+      const authorityState = createAuthorityState({
+        "custom-role": {
+          name: "custom-role",
+          capabilities: ["custom-capability"]
+        }
+      });
+      
+      const capabilities = getRoleCapabilities("custom-role", authorityState);
+      expect(capabilities).toEqual(["custom-capability"]);
+    });
+
+    it("should prefer custom roles over built-in roles", () => {
+      const authorityState = createAuthorityState({
+        "root": {
+          name: "root",
+          capabilities: ["custom-root-capability"]
+        }
+      });
+      
+      const capabilities = getRoleCapabilities("root", authorityState);
+      expect(capabilities).toEqual(["custom-root-capability"]);
+    });
+
+    it("should return empty array for unknown roles", () => {
+      const capabilities = getRoleCapabilities("unknown-role");
+      expect(capabilities).toEqual([]);
+    });
+  });
+
+  describe("hasRole", () => {
+    it("should return true for actors with the specified role", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["moderator"]
+        }
+      });
+      
+      const result = hasRole(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        "moderator",
+        authorityState
+      );
+      expect(result).toBe(true);
+    });
+
+    it("should return false for actors without the specified role", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["user"]
+        }
+      });
+      
+      const result = hasRole(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        "moderator",
+        authorityState
+      );
+      expect(result).toBe(false);
+    });
+
+    it("should return false for unknown actors", () => {
+      const authorityState = createAuthorityState();
+      const result = hasRole(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        "moderator",
+        authorityState
+      );
+      expect(result).toBe(false);
+    });
+
+    it("should normalize pubkeys to lowercase", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["moderator"]
+        }
+      });
+      
+      const result = hasRole(
+        "ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789",
+        "moderator",
+        authorityState
+      );
+      expect(result).toBe(true);
+    });
+  });
+
+  describe("getActorRoles", () => {
+    it("should return roles for known actors", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["user", "trusted-user"]
+        }
+      });
+      
+      const roles = getActorRoles(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        authorityState
+      );
+      expect(roles).toEqual(["user", "trusted-user"]);
+    });
+
+    it("should return empty array for unknown actors", () => {
+      const authorityState = createAuthorityState();
+      const roles = getActorRoles(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        authorityState
+      );
+      expect(roles).toEqual([]);
+    });
+  });
+
+  describe("hasCapability", () => {
+    it("should return true for actors with the specified capability", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["moderator"]
+        }
+      });
+      
+      const result = hasCapability(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        "submit-reports",
+        authorityState
+      );
+      expect(result).toBe(true);
+    });
+
+    it("should return false for actors without the specified capability", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["user"]
+        }
+      });
+      
+      const result = hasCapability(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        "manage-admin-lists",
+        authorityState
+      );
+      expect(result).toBe(false);
+    });
+
+    it("should return false for unknown actors", () => {
+      const authorityState = createAuthorityState();
+      const result = hasCapability(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        "submit-reports",
+        authorityState
+      );
+      expect(result).toBe(false);
+    });
+  });
+
+  describe("getActorCapabilities", () => {
+    it("should return all capabilities for an actor's roles", () => {
+      const authorityState = createAuthorityState({}, {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["moderator", "trusted-user"]
+        }
+      });
+      
+      const capabilities = getActorCapabilities(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        authorityState
+      );
+      
+      // Should have capabilities from both roles, with duplicates removed
+      expect(capabilities).toContain("submit-reports");
+      expect(capabilities).toContain("view-reports");
+      expect(capabilities).toContain("submit-trust-endorsements");
+    });
+
+    it("should return empty array for unknown actors", () => {
+      const authorityState = createAuthorityState();
+      const capabilities = getActorCapabilities(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        authorityState
+      );
+      expect(capabilities).toEqual([]);
+    });
+  });
+
+  describe("createRoleDefinition", () => {
+    it("should create a valid role definition", () => {
+      const role = createRoleDefinition("test-role", ["capability1", "capability2"]);
+      expect(role).toEqual({
+        name: "test-role",
+        capabilities: ["capability1", "capability2"]
+      });
+    });
+
+    it("should trim whitespace from role name and capabilities", () => {
+      const role = createRoleDefinition(" test-role ", [" capability1 ", " capability2 "]);
+      expect(role).toEqual({
+        name: "test-role",
+        capabilities: ["capability1", "capability2"]
+      });
+    });
+
+    it("should throw error for invalid role name", () => {
+      expect(() => createRoleDefinition("", ["capability"])).toThrow();
+      expect(() => createRoleDefinition(/** @type {any} */ (123), ["capability"])).toThrow();
+    });
+
+    it("should throw error for invalid capabilities", () => {
+      expect(() => createRoleDefinition("test-role", /** @type {any} */ ("not-an-array"))).toThrow();
+      expect(() => createRoleDefinition("test-role", [/** @type {any} */ (123)])).toThrow();
+      expect(() => createRoleDefinition("test-role", [""])).toThrow();
+    });
+  });
+
+  describe("createActor", () => {
+    it("should create a valid actor", () => {
+      const actor = createActor(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        ["role1", "role2"]
+      );
+      expect(actor).toEqual({
+        pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        roles: ["role1", "role2"]
+      });
+    });
+
+    it("should normalize pubkey to lowercase", () => {
+      const actor = createActor(
+        "ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789",
+        ["role1"]
+      );
+      expect(actor.pubkey).toBe("abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789");
+    });
+
+    it("should trim whitespace from roles", () => {
+      const actor = createActor(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        [" role1 ", " role2 "]
+      );
+      expect(actor.roles).toEqual(["role1", "role2"]);
+    });
+
+    it("should throw error for invalid pubkey", () => {
+      expect(() => createActor("invalid-pubkey", ["role"])).toThrow();
+      expect(() => createActor(/** @type {any} */ (123), ["role"])).toThrow();
+      expect(() => createActor("", ["role"])).toThrow();
+    });
+
+    it("should throw error for invalid roles", () => {
+      expect(() => createActor(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        /** @type {any} */ ("not-an-array")
+      )).toThrow();
+      expect(() => createActor(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        [/** @type {any} */ (123)]
+      )).toThrow();
+      expect(() => createActor(
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+        [""]
+      )).toThrow();
+    });
+  });
+
+  describe("createAuthorityState", () => {
+    it("should create a valid authority state", () => {
+      const roles = {
+        "test-role": {
+          name: "test-role",
+          capabilities: ["test-capability"]
+        }
+      };
+      
+      const actors = {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789",
+          roles: ["test-role"]
+        }
+      };
+      
+      const state = createAuthorityState(roles, actors);
+      expect(state).toEqual({ roles, actors });
+    });
+
+    it("should create empty authority state with no arguments", () => {
+      const state = createAuthorityState();
+      expect(state).toEqual({ roles: {}, actors: {} });
+    });
+
+    it("should validate role names", () => {
+      const roles = {
+        "": {
+          name: "",
+          capabilities: ["test-capability"]
+        }
+      };
+      
+      expect(() => createAuthorityState(roles)).toThrow();
+    });
+
+    it("should validate role definitions", () => {
+      const roles = {
+        "test-role": /** @type {any} */ (null)
+      };
+      
+      expect(() => createAuthorityState(roles)).toThrow();
+    });
+
+    it("should validate role name consistency", () => {
+      const roles = {
+        "test-role": {
+          name: "different-name",
+          capabilities: ["test-capability"]
+        }
+      };
+      
+      expect(() => createAuthorityState(roles)).toThrow();
+    });
+
+    it("should validate actor pubkeys", () => {
+      const actors = {
+        "invalid-pubkey": {
+          pubkey: "invalid-pubkey",
+          roles: ["test-role"]
+        }
+      };
+      
+      expect(() => createAuthorityState({}, actors)).toThrow();
+    });
+
+    it("should validate actors", () => {
+      const actors = {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": /** @type {any} */ (null)
+      };
+      
+      expect(() => createAuthorityState({}, actors)).toThrow();
+    });
+
+    it("should validate actor pubkey consistency", () => {
+      const actors = {
+        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789": {
+          pubkey: "different-pubkey",
+          roles: ["test-role"]
+        }
+      };
+      
+      expect(() => createAuthorityState({}, actors)).toThrow();
+    });
+  });
+});
\ No newline at end of file