Let plugins give specific agents tools (#7938)

* feat(plugins): attach tools to individual agent sessions

* feat(plugins): reopen idle agent sessions after hook changes

Defer automatic plugin changes until the next idle prompt so running turns keep steering. Expose session reload separately from snapshot refresh in the SDK.

* docs(plugins): show how to attach tools to agents

* test(agent): update permission follow-up adapter

plugin-examples/agent-tools/README.md

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+# Agent tools
+
+Attaches `append_workspace_note` to agents whose `notes/enabled` label is `"true"`.
+Calling the tool with `{ "note": "Run the targeted tests before committing." }` appends that
+line to `AGENT_NOTES.md` in the calling agent's working directory and returns the file path.
+It creates the file if it does not exist.
+
+Install on a daemon with plugins enabled:
+
+```bash
+paseo plugin install /absolute/path/to/plugin-examples/agent-tools
+```
+
+Create a labeled agent through the SDK:
+
+```ts
+const agent = await paseo.agents.create({
+  config: { provider: "codex/gpt-5.4" },
+  cwd: "/projects/shop",
+  labels: { "notes/enabled": "true" },
+});
+```
+
+The session-open callback also runs when an agent resumes or reloads. After changing an existing
+agent's labels, call `paseo.agents.ref(id).reload()` to apply the selection immediately. This
+interrupts a running turn. `refresh()` reads the agent snapshot without reopening its session.
+
+From the repository root, `npm run typecheck` includes this example. Outside this repository,
+use `paseo plugin init` to create the package and TypeScript setup, then copy `index.server.ts`
+and the manifest into that project.
+
+See [Attach tools to agents](../../public-docs/plugins/reference.md#attach-tools-to-agents)
+for targeting, execution, provider gates, collisions, and plugin reload behavior.

plugin-examples/agent-tools/index.server.ts

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+import { writeFile } from "node:fs/promises";
+import path from "node:path";
+import { z } from "zod";
+import { defineAgentTool, type PluginServerContext } from "@getpaseo/plugin/server";
+
+const appendWorkspaceNote = defineAgentTool({
+  name: "append_workspace_note",
+  description: "Append a note to AGENT_NOTES.md in this agent's working directory.",
+  input: z.object({ note: z.string().min(1).describe("Note to append") }),
+  async execute({ note }, { agent, signal }) {
+    const notePath = path.join(agent.cwd, "AGENT_NOTES.md");
+    await writeFile(notePath, `${note}\n`, { encoding: "utf8", flag: "a", signal });
+    return {
+      text: `Saved note to ${notePath}`,
+      structuredContent: { path: notePath },
+    };
+  },
+});
+
+export default function contribute(server: PluginServerContext) {
+  server.before("agent.session_open", ({ request }) => {
+    if (request.labels["notes/enabled"] !== "true") return;
+    return { ...request, tools: [...request.tools, appendWorkspaceNote] };
+  });
+  return () => {};
+}

plugin-examples/agent-tools/paseo-plugin.json

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+{
+  "id": "agent-tools",
+  "requirements": { "paseo": ">=0.13.2" }
+}