feat(bft): Bun File Trace for node:fs / Bun.file() assets in agent builds

[Copilot]

Bun.build() has no awareness of files accessed at runtime via node:fs or Bun.file() — those calls survive in the bundle verbatim, but the referenced files are never copied to the output. This is the same gap Node File Trace (NFT) fills for Node.js deployments.

What changed

packages/aixyz-config — two new build fields

Mirrors Next.js outputFileTracingIncludes / outputFileTracingExcludes. Accepts string | string[], defaults to [].

// aixyz.config.ts
export default {
  build: {
    // Auto-traced (literal readFileSync/Bun.file paths) needs no config.
    // Use these only for files discovered dynamically, e.g. via readdirSync:
    outputFileTracingIncludes: ["prompts/**", "data/*.db"],
    outputFileTracingExcludes: ["data/dev-*"],
  },
} satisfies AixyzConfig;

packages/aixyz-cli/build/nft.ts — new Bun File Trace (BFT) module

Export	Behaviour
traceFileSystemAssets(appDir, cwd)	Regex-scans every source file in app/ for literal-string arguments to readFileSync, readFile, createReadStream, existsSync, statSync, Bun.file(). Resolves paths against both CWD (most common) and import.meta.dir. Returns absolute paths of non-code files that exist on disk.
copyTracedFiles(files, cwd, outputDir)	Copies auto-traced files into the output, preserving CWD-relative paths.
copyAppAssets(appDir, outputDir, includes, excludes)	Manual-override sweep driven by outputFileTracingIncludes / outputFileTracingExcludes. No-op by default.

packages/aixyz-cli/build/index.ts

Both buildBun and buildVercel run all three BFT steps after Bun.build() succeeds. Auto-tracing always runs; the config-driven sweep is opt-in.

packages/aixyz-cli/build/nft.test.ts

13 tests covering: literal-path detection (readFileSync, Bun.file()), template-literal/variable path skipping, absolute-path rejection, code-file exclusion, outputFileTracingExcludes precedence, and the empty-includes no-op default.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• nextjs.org
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[linear]

XYZ-21 Need NFT or BFT support for File-system agents

[vercel]

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
ai-xyz.dev	Ignored		Feb 25, 2026 0:46am