@episcloud/agent

A TypeScript SDK for building coding agents on top of the EpisCloud AI platform. Built for the same patterns developers know from other agent toolkits: a query() async generator, typed tool definitions backed by Zod, a permission system, hooks, and a streaming result protocol.

npm install @episcloud/agent

Node 20+ required.

Quick start

import { query } from '@episcloud/agent';

for await (const msg of query('Review src/auth.ts for OWASP issues', {
  apiKey: process.env.EPISCLOUD_API_KEY!,           // epis_sk_…
  allowedTools: ['Read', 'Glob', 'Grep'],           // read-only inspection
})) {
  if (msg.type === 'stream_event') process.stdout.write(msg.delta);
  if (msg.type === 'tool_use')      console.log('\n→', msg.name, msg.input);
  if (msg.type === 'result')        console.log('\n✓', msg.usage);
}

How it works

The SDK calls the EpisCloud Chat API (/v1/chat/completions) over HTTPS with your epis_sk_ Bearer token. Each tool the agent invokes is run inside your Node process — the SDK never executes anything server-side.

your code  ──►  @episcloud/agent  ──►  paas-ai.episcloud.com
                       │                       │
                       │                       ▼
                       │              ┌──────────────────┐
                       │              │  EpisCloud Chat  │
                       │              │  (auth + bill +  │
                       │              │   model loop)    │
                       │              └──────────────────┘
                       │
                       ▼ runs locally
              Read · Glob · Grep · Edit · Write · Bash · …

Built-in tools

| Tool | Purpose | Default permission | |--------------|------------------------------------------------------|--------------------| | Read | Read file with line offset / limit | allow | | Write | Create / overwrite a file | ask | | Edit | Replace exact string in an existing file | ask | | Glob | Match files by glob (src/**/*.ts) | allow | | Grep | Search regex across the working directory | allow | | Bash | Run a shell command | ask | | TodoWrite | Agent's internal multi-step task tracker | allow |

By default query() enables only the read-only set (Read, Glob, Grep, TodoWrite). Opt in to mutators explicitly:

query(prompt, {
  apiKey: '…',
  allowedTools: ['Read', 'Glob', 'Grep', 'Edit', 'Write', 'Bash'],
  permissions: { Bash: 'ask', Edit: 'allow', Write: 'allow' },
});

Custom tools

import { z } from 'zod';
import { tool, query } from '@episcloud/agent';

const dbQuery = tool({
  name: 'db_query',
  description: 'Run a read-only SQL query against the analytics DB',
  parameters: z.object({
    sql: z.string().describe('SELECT only — DDL/DML rejected'),
    limit: z.number().int().min(1).max(1000).default(100),
  }),
  defaultPermission: 'allow',
  async execute({ sql, limit }) {
    if (!/^\s*select/i.test(sql)) return 'error: only SELECT allowed';
    const rows = await runQuery(sql, limit);
    return JSON.stringify(rows);
  },
});

for await (const msg of query('How many sign-ups last week?', {
  apiKey: process.env.EPISCLOUD_API_KEY!,
  tools: [dbQuery],
})) {
  // …
}

Permission modes

Pass permissionMode to set a coarse policy that overrides per-tool defaults:

| Mode | Effect | |-----------------------|-------------------------------------------------------------------| | default | Honor each tool's defaultPermission + your permissions map | | acceptEdits | Auto-approve file-mutating tools (Write/Edit/MultiEdit) | | plan | Refuse every tool — model must produce a plan in prose | | bypassPermissions | Allow everything (CI / unattended only) |

When a tool is gated by ask, the SDK invokes your onToolApproval:

query(prompt, {
  apiKey: '…',
  onToolApproval: ({ name, input, description }) => {
    if (name === 'Bash' && /rm\s+-rf/.test((input as any).command)) {
      return 'deny';
    }
    return 'allow';
  },
});

Hooks

Hooks fire at lifecycle points and can observe, mutate, or block:

query(prompt, {
  apiKey: '…',
  hooks: {
    PreToolUse: ({ name }) => {
      if (name === 'Write') return { permission: 'deny', reason: 'frozen tree' };
      return {};
    },
    PostToolUse: ({ name, result }) => {
      metrics.record(name, result.length);
    },
    UserPromptSubmit: ({ prompt }) => ({
      prompt: prompt.replace(/<SECRET>/g, '[REDACTED]'),
    }),
  },
});

Available hooks:

• PreToolUse — before a tool runs; can deny
• PostToolUse — after a tool returns
• UserPromptSubmit — before the user prompt reaches the model
• Stop — when the agent decides to finalize; can force another turn
• Notification — surface info/warn events to your UI

Cancellation & budgets

const ctrl = new AbortController();
setTimeout(() => ctrl.abort(), 30_000);   // hard 30s cap

const gen = query(prompt, {
  apiKey: '…',
  signal: ctrl.signal,
  maxTurns: 12,                            // tool-loop iteration cap
  maxCostMicroUSD: 100_000,                // $0.10 budget
  requestTimeoutMs: 60_000,                // per model call
});

for await (const msg of gen) {
  if (msg.type === 'result' && msg.subtype === 'cancelled') {
    console.log('partial result:', msg.result);
  }
}

Messages

query() yields a discriminated union (SDKMessage). Each message carries session_id. Branch on .type:

| Type | When | |----------------|-------------------------------------------------| | system | Once at start (resolved options, tool catalog) | | user | Echo of the prompt | | assistant | One per turn — text + tool calls | | tool_use | The agent invoked a tool | | tool_result | The tool returned (success or is_error=true) | | stream_event | Incremental text/reasoning chunk | | result | Final — has usage, duration_ms, result |

Error handling

import { InsufficientBalanceError, RateLimitError } from '@episcloud/agent';

try {
  for await (const msg of query(prompt, { apiKey: '…' })) { /* … */ }
} catch (err) {
  if (err instanceof InsufficientBalanceError) {
    promptUserToTopUp();
  } else if (err instanceof RateLimitError) {
    await sleep((err.retryAfterSec ?? 5) * 1000);
  } else {
    throw err;
  }
}

Typed errors: AuthenticationError, InsufficientBalanceError, RateLimitError, InvalidOptionsError, MaxTurnsExceededError, BudgetExceededError, ToolExecutionError, ToolDeniedError, TransportError.

CLI

npm install -g @episcloud/agent
episctl-agent run "refactor src/api/client.ts to use fetch"
episctl-agent chat          # interactive REPL

CLI looks for ~/.episcloud/agent-settings.json and the EPISCLOUD_API_KEY env var.

License

MIT