# PlatformClient The HTTP client for the hosted platform API. Use it to manage agents and their signing sessions, read vault data, set policy, and run the card rail — all with an operator API key, no local private key required. ```typescript import { PlatformClient } from "@newton-xyz/isaac"; const platform = new PlatformClient({ baseUrl: "https://api.example.com", apiKey: "nab_sk_...", // operator API key }); ``` You can also get a pre-configured instance from a managed vault with `vault.getPlatformClient()`. ## Agents ```typescript const { address, sessionExpiresAt } = await platform.createAgent("research-bot"); const agents = await platform.listAgents(); const agent = await platform.getAgent(address); await platform.refreshSession(address); // extend the signing session await platform.deactivateAgent(address); ``` `createAgent(name)` provisions a managed key and an initial signing session. `refreshSession(address)` extends a session before it expires; `getAgent`/`listAgents` return the agent's `name`, `hdIndex`, `status`, and `sessionExpiresAt`. ### Signing ```typescript const { signature } = await platform.sign(address, "message", "hello"); ``` `sign(address, type, payload)` signs with the agent's managed key. `type` is `"transaction"`, `"message"`, or `"typed_data"`. ## Vault reads ```typescript const vaults = await platform.listVaults(); const balance = await platform.getVaultBalance(vaultAddress, [tokenAddress]); const fleet = await platform.getVaultAgents(vaultAddress); const history = await platform.getVaultHistory(vaultAddress); const spending = await platform.getVaultSpending(vaultAddress, "day"); const token = await platform.getTokenMetadata(tokenAddress); // symbol, decimals ``` ## Policy Policy is per-agent. Set up an agent's policy module, then update its params. ```typescript const policy = await platform.getAgentPolicy(vaultAddress, agentAddress); await platform.setupPolicy(vaultAddress, agentAddress, "token"); await platform.updatePolicyParams(vaultAddress, agentAddress, params); ``` Build `params` with [buildPolicyParams](/reference/sdk/build-policy-params). `setupPolicy` requires the agent's module to already be installed on the vault. ## Admin transactions These return an unsigned transaction for you to sign and submit — the platform never holds the operator key. ```typescript const tx = await platform.withdrawTx(vaultAddress, tokenAddress, "500000", recipient); await platform.shutdownTx(vaultAddress); await platform.unpauseTx(vaultAddress); ``` ## Card rail Each method takes the vault address and a body object; `simulateCardAuth` also takes the card token. ```typescript await platform.linkCardProgram(vaultAddress, { program_id: "...", api_key: "...", }); const card = await platform.createCard(vaultAddress, { agent_address: agentAddress, // optional — bind the card to an agent }); await platform.setCardPolicy(vaultAddress, { card_policy_params: policy, }); // Sandbox only — simulate an authorization against an issued card. const auth = await platform.simulateCardAuth(vaultAddress, cardToken, { amount: 1000, descriptor: "Coffee Shop", }); ``` See [Issue a Card](/guides/issue-a-card) for the full flow. ## See also * [ModularVault](/reference/sdk/modular-vault) — connect to a vault and read balances. * [FacilitatorClient](/reference/sdk/facilitator-client) — charge agents to call your API.