/agent-prompts

Reusable system prompt fragments + composePrompt() for wasmagent — code/tool/sandbox/output-contract conventions exported as named string constants you compose into your own system prompt.

Part of wasmagent — a TypeScript + WASM agent runtime.

Install

npm install /agent-prompts

Usage

composePrompt() joins fragments with double newlines and trims trailing whitespace — no template engine, no runtime. The fragments are typed const strings, so your IDE auto-completes them and a typo fails the build.

import {
  composePrompt,
  REASONING_FIRST,
  CODE_QUALITY_TYPESCRIPT,
  SANDBOX_QUICKJS,
  OUTPUT_CONTRACT_FINAL_ANSWER,
} from "/agent-prompts";

const system = composePrompt([
  REASONING_FIRST,             // "## Approach (Reasoning-First)" block
  CODE_QUALITY_TYPESCRIPT,     // type-safety, no `any`, exhaustive checks
  SANDBOX_QUICKJS,             // QuickJS-specific: no node:, no native, …
  OUTPUT_CONTRACT_FINAL_ANSWER,// "Return your final answer as …"
]);

// Pass `system` to any wasmagent Agent / Vercel AI SDK / Claude SDK / etc.

Where it's used in this repo

• bscode worker (apps/worker/src/agents/prompts.ts) — composes 13 fragments (CODE_QUALITY_TYPESCRIPT, SANDBOX_QUICKJS, DIAGRAMS_CODE_JS, FILE_OPS_ATOMIC, …) into the production system prompt for bscode's CodeAgent. Each fragment is a generic wasmagent building block; product-specific instructions (persona, <boltThinking> tag, WebContainers conventions) sit alongside.
• tests/integration/cross-package.test.ts — pins the contract that fragments compose without conflict and that composePrompt() is byte-stable across re-orderings.

Fragment catalogue

| Category | Fragments | |---|---| | Approach | REASONING_FIRST, STRUCTURED_PLAN | | Output | OUTPUT_CONTRACT_FINAL_ANSWER, OUTPUT_CONTRACT_STDOUT | | Code | CODE_QUALITY_GENERIC, CODE_QUALITY_TYPESCRIPT, ERROR_RECOVERY, FILE_OPS_ATOMIC | | Sandbox | SANDBOX_QUICKJS, SANDBOX_PYODIDE, SANDBOX_NODE | | Diagrams | re-exported from ./diagrams (DIAGRAMS_CODE_JS, DIAGRAMS_CODE_PY, …) |

The full surface lives in src/fragments.ts and src/diagrams.ts.

Why these particular fragments

The fragments were extracted from production system prompts that survived contact with real users (bscode in production since 2026-04, wasmagent's own examples in CI). Each one solves a recurring failure mode — e.g. CODE_QUALITY_TYPESCRIPT exists because models default to writing untyped JS; SANDBOX_QUICKJS exists because models attempt require('fs') on a kernel that has no fs.

License

Apache-2.0 — © wasmagent contributors