diff --git a/packages/agentstack/src/index.ts b/packages/agentstack/src/index.ts
index 92f84ef..f84b443 100644
--- a/packages/agentstack/src/index.ts
+++ b/packages/agentstack/src/index.ts
@@ -24,93 +24,125 @@ export const agentDid = (id: string) => makeDid("agent", id);
 /** Parse a CoinPay DID into its kind and id, or return null if it is not one. */
 export function parseDid(did: string): { kind: DidKind; id: string } | null {
   const prefix = `${DID_METHOD}:`;
-  if (!did.startsWith(prefix)) return null;
-  const [kind, id] = did.slice(prefix.length).split(":");
-  if ((kind !== "user" && kind !== "agent") || !id) return null;
-  return { kind, id };
-}
-
-export function isDidTask(value: unknown): value is DidTask {
-  return (
-    typeof value === "object" &&
-    value !== null &&
-    typeof (value as DidTask).id === "string" &&
-    typeof (value as DidTask).ownerDid === "string" &&
-    typeof (value as DidTask).status === "string"
-  );
-}
-
-const TERMINAL: ReadonlySet<TaskStatus> = new Set(["complete", "failed", "cancelled"]);
-
-/**
- * In-memory AgentStack coordinator: registers agents, tracks portable tasks through their
- * lifecycle, records delegation grants, and emits coordination events. Reference
- * implementation of the `agentstack` capability; storage backends can wrap the same API.
- */
-export class AgentStack {
-  private readonly agents = new Map<string, AgentProfile>();
-  private readonly tasks = new Map<string, DidTask>();
-  private readonly delegations = new Map<string, DelegationGrant>();
-  private readonly listeners = new Set<AgentStackListener>();
-  private seq = 0;
-
-  constructor(private readonly now: () => string = () => new Date().toISOString()) {}
-
-  on(listener: AgentStackListener): () => void {
-    this.listeners.add(listener);
-    return () => this.listeners.delete(listener);
-  }
-
-  private emit(event: AgentStackEvent) {
-    for (const listener of this.listeners) listener(event);
-  }
-
-  private nextId(prefix: string): string {
-    this.seq += 1;
-    return `${prefix}_${this.seq}`;
-  }
-
-  registerAgent(agent: AgentProfile): AgentProfile {
-    if (!parseDid(agent.did)) {
-      throw new Error(`Invalid agent DID: ${agent.did}`);
-    }
-    this.agents.set(agent.did, agent);
-    this.emit({ type: "agent.registered", agent });
-    return agent;
-  }
-
-  getAgent(did: string): AgentProfile | undefined {
-    return this.agents.get(did);
-  }
-
-  createTask(input: CreateTaskInput): DidTask {
-    if (!parseDid(input.ownerDid)) {
-      throw new Error(`Invalid owner DID: ${input.ownerDid}`);
-    }
-    const ts = this.now();
-    const task: DidTask = {
-      id: this.nextId("task"),
-      ownerDid: input.ownerDid,
-      assigneeDid: input.assigneeDid,
-      sourceApp: input.sourceApp,
-      title: input.title,
-      description: input.description,
-      status: input.assigneeDid ? "queued" : "pending",
-      paymentIntentId: input.paymentIntentId,
-      escrowId: input.escrowId,
-      metadata: input.metadata,
-      createdAt: ts,
-      updatedAt: ts
-    };
-    this.tasks.set(task.id, task);
-    this.emit({ type: "task.created", task });
-    return task;
-  }
-
-  getTask(id: string): DidTask | undefined {
-    return this.tasks.get(id);
-  }
-
+import type { PluginDefinition } from "@logicsrc/plugin-core";
+import { agentStackManifest } from "./manifest.js";
+import type {
+  AgentProfile,
+  AgentStackEvent,
+  AgentStackListener,
+  AgentStackSnapshot,
+  CreateTaskInput,
+  DelegationGrant,
+  DidKind,
+  DidTask,
+  TaskStatus
+} from "./types.js";
+import { DID_METHOD } from "./types.js";
+
+/** Build a CoinPay-method DID for a user or agent: `did:coinpay:user:123`. */
+export function makeDid(kind: DidKind, id: string): string {
+  return `${DID_METHOD}:${kind}:${id}`;
+}
+
+export const userDid = (id: string) => makeDid("user", id);
+export const agentDid = (id: string) => makeDid("agent", id);
+
+/** Parse a CoinPay DID into its kind and id, or return null if it is not one. */
+export function parseDid(did: string): { kind: DidKind; id: string } | null {
+  const prefix = `${DID_METHOD}:`;
+  if (!did.startsWith(prefix)) return null;
+  const [kind, id] = did.slice(prefix.length).split(":");
+  if ((kind !== "user" && kind !== "agent") || !id) return null;
+  return { kind, id };
+}
+
+export function isDidTask(value: unknown): value is DidTask {
+  return (
+    typeof value === "object" &&
+    value !== null &&
+    typeof (value as DidTask).id === "string" &&
+    typeof (value as DidTask).ownerDid === "string" &&
+    typeof (value as DidTask).status === "string"
+  );
+}
+
+/** Return false if the grant has an expiresAt that is in the past compared to `now`. */
+export function isGrantActive(grant: DelegationGrant, now: string): boolean {
+  if (!grant.expiresAt) return true;
+  return grant.expiresAt > now;
+}
+
+const TERMINAL: ReadonlySet<TaskStatus> = new Set(["complete", "failed", "cancelled"]);
+
+/**
+ * In-memory AgentStack coordinator: registers agents, tracks portable tasks through their
+ * lifecycle, records delegation grants, and emits coordination events. Reference
+ * implementation of the `agentstack` capability; storage backends can wrap the same API.
+ */
+export class AgentStack {
+  private readonly agents = new Map<string, AgentProfile>();
+  private readonly tasks = new Map<string, DidTask>();
+  private readonly delegations = new Map<string, DelegationGrant>();
+  private readonly listeners = new Set<AgentStackListener>();
+  private seq = 0;
+
+  constructor(private readonly now: () => string = () => new Date().toISOString()) {}
+
+  on(listener: AgentStackListener): () => void {
+    this.listeners.add(listener);
+    return () => this.listeners.delete(listener);
+  }
+
+  private emit(event: AgentStackEvent) {
+    for (const listener of this.listeners) listener(event);
+  }
+
+  private nextId(prefix: string): string {
+    this.seq += 1;
+    return `${prefix}_${this.seq}`;
+  }
+
+  registerAgent(agent: AgentProfile): AgentProfile {
+    if (!parseDid(agent.did)) {
+      throw new Error(`Invalid agent DID: ${agent.did}`);
+    }
+    this.agents.set(agent.did, agent);
+    this.emit({ type: "agent.registered", agent });
+    return agent;
+  }
+
+  getAgent(did: string): AgentProfile | undefined {
+    return this.agents.get(did);
+  }
+
+  createTask(input: CreateTaskInput): DidTask {
+    if (!parseDid(input.ownerDid)) {
+      throw new Error(`Invalid owner DID: ${input.ownerDid}`);
+    }
+    const ts = this.now();
+    const task: DidTask = {
+      id: this.nextId("task"),
+      ownerDid: input.ownerDid,
+      assigneeDid: input.assigneeDid,
+      sourceApp: input.sourceApp,
+      title: input.title,
+      description: input.description,
+      status: input.assigneeDid ? "queued" : "pending",
+      paymentIntentId: input.paymentIntentId,
+      escrowId: input.escrowId,
+      metadata: input.metadata,
+      createdAt: ts,
+      updatedAt: ts
+    };
+    this.tasks.set(task.id, task);
+    this.emit({ type: "task.created", task });
+    return task;
+  }
+
+  getTask(id: string): DidTask | undefined {
+    return this.tasks.get(id);
+  }
+
   assignTask(taskId: string, agentDidValue: string): DidTask {
     const task = this.requireTask(taskId);
     if (TERMINAL.has(task.status)) {
@@ -119,70 +151,6 @@ export class AgentStack {
     if (!this.agents.has(agentDidValue)) {
       throw new Error(`Unknown agent: ${agentDidValue}`);
     }
-    const updated: DidTask = {
-      ...task,
-      assigneeDid: agentDidValue,
-      status: task.status === "pending" ? "queued" : task.status,
-      updatedAt: this.now()
-    };
-    this.tasks.set(taskId, updated);
-    this.emit({ type: "task.assigned", task: updated });
-    return updated;
-  }
-
-  updateTaskStatus(
-    taskId: string,
-    status: TaskStatus,
-    patch: Partial<Pick<DidTask, "reputationEventId" | "paymentIntentId" | "escrowId" | "metadata">> = {}
-  ): DidTask {
-    const task = this.requireTask(taskId);
-    if (TERMINAL.has(task.status)) {
-      throw new Error(`Task ${taskId} is already ${task.status} and cannot transition to ${status}`);
-    }
-    const updated: DidTask = { ...task, ...patch, status, updatedAt: this.now() };
-    this.tasks.set(taskId, updated);
-    this.emit({ type: "task.updated", task: updated });
-    return updated;
-  }
-
-  /** Grant an agent authority to act for an owner. */
-  delegate(ownerDidValue: string, agentDidValue: string, scopes: string[], expiresAt?: string): DelegationGrant {
-    if (!parseDid(ownerDidValue)) throw new Error(`Invalid owner DID: ${ownerDidValue}`);
-    if (!this.agents.has(agentDidValue)) throw new Error(`Unknown agent: ${agentDidValue}`);
-    const grant: DelegationGrant = {
-      id: this.nextId("grant"),
-      ownerDid: ownerDidValue,
-      agentDid: agentDidValue,
-      scopes,
-      expiresAt,
-      createdAt: this.now()
-    };
-    this.delegations.set(grant.id, grant);
-    this.emit({ type: "delegation.granted", grant });
-    return grant;
-  }
-
-  revokeDelegation(grantId: string): DelegationGrant {
-    const grant = this.delegations.get(grantId);
-    if (!grant) throw new Error(`Unknown delegation grant: ${grantId}`);
-    this.delegations.delete(grantId);
-    this.emit({ type: "delegation.revoked", grant });
-    return grant;
-  }
-
-  listTasks(filter?: { ownerDid?: string; assigneeDid?: string; status?: TaskStatus }): DidTask[] {
-    return [...this.tasks.values()].filter((task) => {
-      if (filter?.ownerDid && task.ownerDid !== filter.ownerDid) return false;
-      if (filter?.assigneeDid && task.assigneeDid !== filter.assigneeDid) return false;
-      if (filter?.status && task.status !== filter.status) return false;
-      return true;
-    });
-  }
-
-  snapshot(): AgentStackSnapshot {
-    return {
-      agents: [...this.agents.values()],
-      tasks: [...this.tasks.values()],
       delegations: [...this.delegations.values()]
     };
   }