# esbuild

Runs the esbuild bundler and returns structured errors, warnings, and output files.

Agent View of the PolicyLayer registry record for `esbuild`. HTML page: https://policylayer.com/tools/io-github-dave-london-cargo/esbuild

## Facts

- Tool: `esbuild`
- Server: Cargo (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-cargo.md
- Homepage: https://github.com/Dave-London/pare
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "esbuild",
    "arguments": {}
  }
}
```

## Why esbuild is rated High

The tool executes an external bundler (esbuild) which runs arbitrary build scripts and processes files. This constitutes running an external operation whose effects depend on arguments. It could be misused to process malicious input files, execute build scripts, or write output files to arbitrary locations.

From the tool's own definition: "'Runs the esbuild bundler' — actively executes an external build tool process"

## Use case

AI agents invoke esbuild to trigger actions in Cargo. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Cargo:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "esbuild": {
      "limits": [
        {
          "counter": "esbuild_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Cargo (201)

- `branch` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/branch.md
- `clean` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/clean.md
- `pr-close` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/pr-close.md
- `remove` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/remove.md
- `reset` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/reset.md
- `secret-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/secret-delete.md
- `tag` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/tag.md
- `variable-delete` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/variable-delete.md
- `workspace` — Destructive — https://policylayer.com/tools/io-github-dave-london-cargo/workspace.md
- `add` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/add.md
- `add-package` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/add-package.md
- `ansible-galaxy` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/ansible-galaxy.md
- `ansible-playbook` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/ansible-playbook.md
- `api` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/api.md
- `apply` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/apply.md
- `bazel` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/bazel.md
- `biome-check` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/biome-check.md
- `bisect` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/bisect.md
- `black` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/black.md
- `build` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/build.md
- `bundle-exec` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/bundle-exec.md
- `bundle-install` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/bundle-install.md
- `check` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/check.md
- `cherry-pick` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/cherry-pick.md
- `clippy` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/clippy.md
- `cmake` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/cmake.md
- `compose-build` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/compose-build.md
- `compose-down` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/compose-down.md
- `compose-up` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/compose-up.md
- `conda` — Execute — https://policylayer.com/tools/io-github-dave-london-cargo/conda.md
- …and 171 more: https://policylayer.com/tools/io-github-dave-london-cargo.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-dave-london-cargo · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-dave-london-cargo