audit_sourcemap_match
Validate that .map files in a dist directory align with their compiled .js counterparts.
LABSCO SUMMARY
A production stack trace stops being a dead end.
The frames come back as real files and lines with the surrounding code attached, and the trace can be handed over as a raw crash payload from Sentry, Bugsnag or Datadog rather than copied out by hand first.
What it is
A source-map reader for production errors. Give it a stack trace full of hashed bundle names and column offsets, and it returns the original files, lines and columns — plus the code around them. The running server answers with seven tools.
What you get
- A minified stack trace decoded into original TypeScript locations, with the frames it could not map counted rather than dropped
- The source lines surrounding a mapped location, with a pointer at the column
- A check that the .map files in a dist directory line up with the compiled .js files they claim to describe
- Verification that a production bundle matches its source map, using the Debug IDs embedded in both
- Bundler-specific paths — webpack://, ng://, Vite's /@fs/ — resolved to real files on disk
- Crash payloads from Sentry, Bugsnag or Datadog ingested directly and returned as retraced frames
- Async boundaries followed, so a frame that surfaced inside a microtask can be traced back to what scheduled it
Requirements
Node, through the published npm package, and the .map files for the build that produced the trace — the retrace is only as good as the maps you point it at.
Setup effort
One command — npx -y sourcemap-retrace-mcp
USE CASES
01
Finding the code behind a production crash
Paste the minified trace and the directory holding your .map files. What comes back is function names, source files and line numbers — with the source lines around the failure point ready to read.
02
Taking a crash straight from your monitoring tool
Sentry, Bugsnag and Datadog payloads are accepted as they arrive, so the step where somebody reformats a JSON dump into a stack trace disappears.
03
Working out why the frames came back wrong
A retrace that points at nonsense usually means stale or mismatched maps. Check that the bundle and its map share a Debug ID, and that the maps in dist match the files beside them.
04
Catching broken maps before you deploy
Audit the dist directory as a release step — missing maps, or maps pointing at sources that no longer exist, are cheaper to find now than during an incident.
05
Chasing an error that surfaced in the wrong place
When the failure appears inside an await or a queue drain, follow the async boundary back to the code that scheduled the work rather than debugging the runtime's own frames.
06
Making sense of framework bundle paths
webpack://, ng:// and Vite's /@fs/ references get resolved to files you can actually open, so a mapped frame leads somewhere.
7 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
ingest_telemetry_payload
Directly ingest Sentry, Bugsnag, or Datadog crash dumps and return fully retraced stack frames.
normalize_bundler_paths
Resolve dynamic bundle references (like webpack://, ng://, or Vite /@fs/ paths) to raw files.
retrace_stack
Decode a minified production stack trace back to original TypeScript source files, lines, and columns.
retrieve_code_context
Show the original source code lines surrounding a mapped error location.
surface_async_causality
Detect and trace across async boundaries (e.g. await, processTicksAndMicrotasks) to locate scheduling origins.
verify_debug_id_integrity
Validate that a minified production bundle matches its source map using embedded Debug IDs.
BEFORE YOU INSTALL
What to know first
Tools you get
7 tools when we connected.
Requires
npx on PATH
CONTEXT COST
Light Standing cost
Rated by the size of the 7 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Add the block to your client, or run the command directly.
Server setup
Configuration file
JSON
{
"mcpServers": {
"sourcemap-retrace-mcp": {
"command": "npx",
"args": [
"-y",
"sourcemap-retrace-mcp"
]
}
}
}npx
TERMINAL
npx -y sourcemap-retrace-mcp
