Numbers LE

---

Useful? A star or rating is how other developers find it — ★ GitHub · ★ Open VSX · ★ Marketplace

What it does

Open a file, press Ctrl+Alt+N (Cmd+Alt+N on Mac), and every numeric value in the document lands in a new editor — deduplicate and sort it from there. Works in VS Code and in VS Code–based editors like Cursor and VSCodium (installable from Open VSX).

• Data validation — pull the numbers out of a config or fixture and eyeball ranges at a glance
• Config audits — compare ports, thresholds, and limits across INI/TOML/.env files
• CSV work — extract everything, one column, or several columns into separate documents

Install

Where	What you get	Install
VS Code	The same extraction, in your editor, on a keystroke	Marketplace
Cursor, VSCodium, Windsurf	The same extension	Open VSX
A terminal or a CI step	The same run over a whole tree, with exit codes	cargo install numbers-le · crates.io
Any MCP agent, via Node	extract_numbers over stdio	npx numbers-le-mcp · npm
Zed	The MCP server as a context server	add it by hand (no listing yet)

Use it from an AI agent

The same engine runs as an MCP server, so an agent can call it directly instead of you running a command.

Editor	How
VS Code 1.101+	Nothing to install — the extension registers extract_numbers with agent mode
Zed	No listing yet — add the MCP server by hand
Claude Code	claude mcp add numbers-le -- npx -y numbers-le-mcp
Cursor, Windsurf, anything else	point it at npx numbers-le-mcp

extract_numbers(content, format?, filename?, dedupe?, maxResults?)

Returns the values in document order, capped at 500 by default with meta.truncated. A format is optional — anything unrecognised is scanned as plain text rather than refused.

The server takes content and returns data — it reads no files and makes no network requests of its own. Published as numbers-le-mcp on npm and as io.github.nolindnaidoo/numbers-le in the MCP registry.

Most hosts read a JSON config. Add one entry:

{
  "mcpServers": {
    "numbers-le": {
      "command": "npx",
      "args": ["-y", "numbers-le-mcp"]
    }
  }
}

-y skips the install prompt on first run. Pin a version if you would rather not track releases — numbers-le-mcp@2.3.1.

Prefer not to go through npx on every launch? Install it once and point at the binary instead:

npm install -g numbers-le-mcp

{
  "mcpServers": {
    "numbers-le": { "command": "numbers-le-mcp" }
  }
}

It speaks MCP over stdio and needs no environment variables, no API key and no configuration of its own. To check it before wiring it into anything:

echo '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | npx -y numbers-le-mcp

That prints the tool list and exits — if you see extract_numbers, the server works.

Supported formats

Format	What counts as a number
JSON	Number values anywhere in the structure. Quoted numbers ("42") are strings, not numbers, and are never extracted
YAML	Number values, including hex/octal int forms and exponents; multi-document (---) streams extract from every document
TOML	Integer and float values (dates are not numbers)
CSV	Cells whose entire content is numeric — 19.99 counts, 12abc and 1,000 do not. No header inference: every row is data
INI	Values whose entire content is numeric (INI values are inherently strings)
Environment	Values whose entire content is numeric (PORT=3000 yields 3000; VERSION=1.2.3 yields nothing)

The shared policy (one heuristics module, applied to every format): only finite numbers are extracted — NaN and inf/.inf never appear in results — and a coerced string must be numeric in full: plain decimals with optional sign, decimal point, and exponent.

Python, Rust, Go, Java, Kotlin, C#, C, C++, JavaScript, TypeScript, SQL and shell are read by a numeric-literal extractor that understands hex 0xFF, binary 0b1010, octal 0o755 and legacy 0755, digit separators 1_000_000 and 1'000, and suffixes 123n, 1.5f, 10u32, 100L — and that knows u32 is a type name, not the number 32. A dialect changes an answer: 0755 is 493 in C, C++, Go and Java, and 755 in Rust, Python 3, Kotlin and C#.

Every finding carries the notation it was written in — decimal, hex, binary, octal, scientific, bigint. For anything left over you can pick a format explicitly or fall back to a plain-text scan (no grammar: v1.2.3 reads as 1.2 and 0.3).

The CLI

The same extraction runs from a terminal or a shell pipeline: a Rust CLI in crate/, sharing one corpus with the extension — crate/fixtures/ — so the two can never read a document differently.

numbers-le .                     # every number in the tree, as JSON
numbers-le --values config/      # just the numbers, one per line
numbers-le mcp                   # the same extraction over MCP on stdio

# the point of the whole thing:
numbers-le --values --dedupe src/ | sort -n > after.txt
diff before.txt after.txt        # what constants moved this release

Somebody has to verify that the rate in the code is the rate in the specification. A tax percentage, a retention window, a rounding boundary. In a regulated setting that check is a deliverable, and the person doing it usually has no checkout and never has the editor open.

Numbers are printed exactly as JavaScript prints them — 1e+21, not Rust's 1000000000000000000000. This tool's whole output is numbers as text, so the rendering is the contract, and the corpus pins it.

Exit codes follow grep — 0 numbers found, 1 none found, 2 the question was malformed.

Commands

Command	Description
Numbers-LE: Extract Numbers (Ctrl+Alt+N / Cmd+Alt+N)	Extract all numbers from the active document
Numbers-LE: Deduplicate Numbers	Remove duplicate numbers from the results
Numbers-LE: Sort Numbers	Sort results numerically or by magnitude
Numbers-LE: Toggle CSV Streaming	Flip csv.streamingEnabled for large CSV files
Numbers-LE: Open Settings	Open Numbers-LE settings
Numbers-LE: Help & Troubleshooting	Built-in documentation

Settings

Setting	Default	Description
numbers-le.openResultsSideBySide	true	Open results beside the current editor
numbers-le.postProcess.openInNewFile	true	Dedupe/Sort write to a new file instead of replacing the editor content
numbers-le.copyToClipboardEnabled	false	Also copy results to the clipboard (non-CSV)
numbers-le.dedupeEnabled	false	Deduplicate automatically during extraction
numbers-le.sortEnabled	false	Sort automatically during extraction
numbers-le.sortMode	off	numeric-asc/desc, magnitude-asc/desc
numbers-le.csv.streamingEnabled	false	Incremental CSV parsing for large files
numbers-le.showParseErrors	false	Surface parse errors as notifications
numbers-le.notificationsLevel	silent	all = every notification, important = warnings + errors, silent = errors only
numbers-le.safety.enabled	true	Guardrails for very large files/outputs
numbers-le.safety.fileSizeWarnBytes	1000000	Warn above this file size
numbers-le.safety.largeOutputLinesThreshold	50000	Offer Open/Copy/Cancel above this result count
numbers-le.safety.manyDocumentsThreshold	8	Confirm before opening this many column documents
numbers-le.statusBar.enabled	true	Show the status bar item
numbers-le.telemetryEnabled	false	Local-only event log (see Privacy)

Languages

Twelve languages besides English:

German · Spanish · French · Indonesian · Italian · Japanese · Korean · Portuguese (Brazil) · Russian · Ukrainian · Vietnamese · Chinese (Simplified)

Both halves are covered — the manifest (command titles, setting names and descriptions) and everything shown while the extension runs (notifications, the status bar, quick-picks and prompts). The extension follows VS Code's display language, so it matches whatever the editor is already set to; no setting of its own.

Privacy & security

• No network access. The extension never sends data anywhere. The telemetryEnabled setting only writes events to a local Output Channel you can inspect (Numbers-LE).
• The MCP server holds the same line. It takes content as an argument and returns data: no filesystem access, no network calls, no telemetry. Your agent already has file-read tools, so duplicating them inside the server would add a path-traversal surface for no capability. check:mcp-bundle fails the build if the server ever imports something that could reach either.
• Error notifications redact home directories and credential-shaped fragments.

Documentation

What	Where
What the tool is allowed to say — scope, output contract, refusals, non-goals	crate/SPEC.md
How the extension is built and held together — architecture, invariants, toolchain, release	AGENTS.md
How the CLI is built and held together	crate/AGENTS.md
What changed	CHANGELOG.md · crate/CHANGELOG.md
The tool's page, and the other fifteen	letools.dev/tools/numbers-le

Performance

Input	Size	Found	Time	Rate	Scan speed
JSON metrics	2.18 MB	120,000	22.32 ms	5,376,475/sec	97.9 MB/s
CSV data	0.93 MB	150,000	51.26 ms	2,926,066/sec	18.2 MB/s
INI config	0.42 MB	30,000	20.05 ms	1,496,430/sec	20.7 MB/s

Median of 7 runs after warmup, on Apple M5 Pro, 24 GB RAM, Node 24.3.0. Inputs are generated by scripts/benchmark.ts rather than checked in, so the sizes above are exactly what was measured. Reproduce with bun run benchmark.

These are machine-specific and are not asserted in CI — a benchmark that gates a build only tells you how busy the runner was.

Testing

Metric	Coverage
Statements	90.65%
Branches	84.08%
Functions	96.34%
Lines	92.42%

358 test cases across 23 files, plus an integration suite that runs in a real VS Code extension host and an end-to-end test that installs the built .vsix into a clean profile.

Generated from a real run — coverage/coverage-summary.json and coverage/test-results.json — by scripts/coverage-readme.js; CI fails if this section drifts. Reproduce with bun run test:coverage, and the case count is the one vitest prints.

More from the LE family

Sixteen single-purpose tools for the work in front of every model. Each ships a Rust CLI and an MCP server. One page: letools.dev

Get it out

• String-LE — Extract every string in a codebase, with its position, so a person can read them
• Numbers-LE — Extract every hardcoded number in a codebase, so a person can check them
• Units-LE — Extract every quantity with its unit, normalized, and refuse the ambiguous ones by name
• Dates-LE — Extract every date and timestamp, and the exact instant each one resolves to
• IDs-LE — Extract every UUID, ULID, NanoID, ObjectId and Snowflake, and decode the time inside
• IPs-LE — Extract every IP address, CIDR block and MAC, normalized and classified by scope
• URLs-LE — Extract every URL in a codebase, with its protocol and exact position
• Paths-LE — Extract every file path in a codebase, and say whether it still points at anything
• Colors-LE — Extract every color in a codebase, and say which ones are not in your palette

Check it

• Regex-LE — Find every regex in a codebase, and report which can be driven into catastrophic backtracking
• Versions-LE — Find where one dependency is constrained differently across a repository's manifests
• i18n-LE — Identify the i18n library a project uses, then audit its catalogs by that library's rules
• Scrape-LE — Check whether a page is scrapeable before the scraper is written, and say when it cannot tell

Guard it

• Secrets-LE — Find hardcoded credentials in a codebase, and never print one into the report
• EnvSync-LE — Compare the dotenv files in a tree, and say which keys are missing from which
• Unicode-LE — Find the Unicode that hides meaning — bidi controls, invisibles, homoglyphs, mixed scripts

Each stands on its own: no shared crate, no published core. Where two of them agree, it is because the same answer was right twice.

Contact — nolindnaidoo.com · GitHub · LinkedIn

Also by nolindnaidoo

Rust — pixelcoords and pixelactions are one loop: pixelcoords answers where, pixelactions acts there. Their own tools, their own voice — not part of the LE family.

• pixelcoords — Freeze your screen, mark regions, get pixel-exact coordinates and crops pixelcoords.dev · crates.io · docs.rs
• pixelactions — Consume human-verified coordinates, perform the interaction, confirm it landed pixelactions.dev · crates.io · docs.rs

License

MIT © nolindnaidoo