Build agents your way.
Theo runs the rest

1import { Agent, defineTool } from "@theokit/sdk";
2import { z } from "zod";
 
4const refund = defineTool({
5  name: "refund_order",
6  description: "Refund an order by id",
7  inputSchema: z.object({ orderId: z.string() }),
8  handler: async ({ orderId }) => {
9    await billing.refund(orderId);
10    return `Refunded ${orderId}`;
11  },
12});
 
14const agent = await Agent.create({
15  model: "claude-sonnet-4-6",
16  tools: [refund],
17});
 
19const run = await agent.send("Refund order #8814");

1import { defineTool } from "@theokit/sdk";
2import { z } from "zod";
 
4export const refund = defineTool({
5  name: "process_refund",
6  description: "Issue a refund for an order",
7  inputSchema: z.object({
8    orderId: z.string(),
9    reason: z.string(),
10  }),
11  handler: async ({ orderId, reason }) => {
12    await billing.refund(orderId, reason);
13    return `Refunded ${orderId}: ${reason}`;
14  },
15});

1import { createLocalMemory } from "@usetheo/memory";
 
3const memory = await createLocalMemory({
4  vectorStore, embedder, llm,
5});
 
7// Remember across sessions
8await memory.user("u_42").remember("Prefers terse answers");
 
10// Recall by meaning, not keywords
11const facts = await memory.user("u_42").recall("tone");

1import { createVectorRetriever } from "@usetheo/rag/retrievers";
 
3const retriever = createVectorRetriever({ pool, embedder });
 
5// The exact source chunks that ground an answer
6const chunks = await retriever.retrieve({
7  query: "What is our refund window?",
8  top_k: 3,
9  strategy: "vector",
10});

1import {
2  createGuardrailPipeline,
3  createPiiGuardrail,
4  createCredentialMaskingGuardrail,
5  createShellPatternGuardrail,
6} from "@usetheo/trust-guardrails";
 
8// Inline, fail-closed — runs before the model acts
9const guardrails = createGuardrailPipeline([
10  { guardrail: createPiiGuardrail(), options: { name: "pii" } },
11  { guardrail: createCredentialMaskingGuardrail(), options: { name: "creds" } },
12  { guardrail: createShellPatternGuardrail(), options: { name: "shell" } },
13]);
 
15const result = await guardrails.run({ content: input, direction: "input" });

1import { initTheoLens, startAgent } from "@usetheo/lens-sdk";
 
3// Instrument in a few lines — every LLM,
4// tool, and memory call is auto-traced.
5const lens = initTheoLens({
6  endpoint: "http://localhost:4318",
7  serviceName: "support-agent",
8});
 
10await startAgent(lens.tracer, "checkout", async () =>
11  agent.send("Refund order #8814"),
12);