T13 — Tool description .txt pattern

{`
import DESCRIPTION from "./bash.txt"
import { Tool } from "./tool"

export const BashTool = Tool.define("bash", Effect.gen(function* () => {
  const agent = yield* Agent
  return {
    description: renderTemplate(DESCRIPTION, {
      PLATFORM: process.platform,
      SHELL:    process.env.SHELL ?? "bash",
      MAX_LINES: 2000,
    }),
    parameters: z.object({
      command: z.string(),
      timeout: z.number().optional(),
    }),
    // execute: ...
  }
}))
`}

{`
Execute shell commands in a persistent {SHELL} session on {PLATFORM}.

<important-rules>
- DO NOT use `find` or `grep` — use the dedicated Grep/Glob tools instead.
- Quote paths with spaces: cd "path with spaces"
- Output is truncated to {MAX_LINES} lines. Full output saved to disk.
- Prefer absolute paths to avoid cwd ambiguity.
</important-rules>

<when-to-use>
Use when you need to run build commands, install packages, execute tests,
or any shell operation not covered by specialized tools.
</when-to-use>

<when-not-to-use>
- Reading files: use Read tool instead (structured output)
- Searching code: use Grep/Glob tools instead (faster, scoped)
- Editing files: use Edit tool instead (fuzzy matching + validation)
</when-not-to-use>
`}

{`
function renderTemplate(
  template: string,
  vars: Record<string, string | number>
): string {
  return template.replace(/\{(\w+)\}/g, (_, key) => {
    const val = vars[key]
    if (val === undefined) throw new Error(`Template var {${key}} not provided`)
    return String(val)
  })
}

// A/B test: swap file nội dung mà không đổi code
const descriptionV2 = renderTemplate(await readFile("bash-v2.txt", "utf8"), vars)
`}

{`
// tsconfig.json — thêm để TypeScript hiểu text import
{
  "compilerOptions": {
    "moduleResolution": "bundler"
  }
}

// my-tool.ts
import DESCRIPTION from "./my-tool.txt"

export const MyTool = defineTool({
  name: "my_tool",
  description: renderTemplate(DESCRIPTION, {
    MAX_OUTPUT: 5000,
    PLATFORM: process.platform,
  }),
  // ...
})
`}

{`
import { readFileSync } from "node:fs"
import { join, dirname } from "node:path"
import { fileURLToPath } from "node:url"

const __dirname = dirname(fileURLToPath(import.meta.url))
const DESCRIPTION = readFileSync(join(__dirname, "my-tool.txt"), "utf8")
`}