[Numbers-LE Logo]
Numbers-LE: Zero Hassle Number Extraction
Pull every number out of the current file in one keystroke
JSON/JSONC, YAML, CSV/TSV, TOML, INI, Environment files, and twelve source languages
[Install from VS Code Marketplace]
[Open VSX downloads]
[numbers-le-mcp on npm]
[numbers-le on npm]
[numbers-le on crates.io]
[LE Tools]
[Numbers-LE in VS Code]
Useful? A star or rating is how other developers find it —
★ GitHub ·
★ Open VSX ·
★ Marketplace
What it does
Open a file, run Numbers-LE: Extract Numbers, 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
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.
[An agent in Claude Code calling the numbers-le MCP server]
Returns the values in document order, each with the notation it was written in and — for JSON, source code and plain text, where the position is exact — its 1-based line and column; a parsed format (YAML, TOML, CSV, INI, dotenv) carries no position rather than a guessed one. 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.
Configuring it by hand — any host with an MCP config file
Most hosts read a JSON config. Add one entry:
-y skips the install prompt on first run. Pin a version if you would rather not track releases — [email protected].
Prefer not to go through npx on every launch? Install it once and point at the binary instead:
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:
That prints the tool list and exits — if you see extract_numbers, the server works.
Supported formats
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. Install it from npm with npm install -g numbers-le
(or run it with npx numbers-le) or from crates.io with
cargo install numbers-le. Both install the same command and are held to
the same output byte for byte, apart from the words a parser uses to refuse
a broken document.
[numbers-le in a terminal]
Install it from npm (numbers-le) or from crates.io (numbers-le). Both install the same numbers-le command.
[numbers-le on npm]
[numbers-le on crates.io]
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
No command is bound to a key by default. Give any of them one under Keyboard Shortcuts in the editor.
Settings
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.
- One rating prompt, at most twice. On the 3rd successful use the extension asks once whether you would rate it, and once more on the 20th if you chose Later or dismissed it. Don't Ask Again ends it. Setting
notificationsLevel to important or silent yourself turns it off. The counts are kept in VS Code's extension storage and nothing is sent anywhere; Rate opens the listing you installed from — the VS Code Marketplace or Open VSX — in your browser.
Documentation
Performance
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
526 test cases across 37 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, and
bun run coverage:readme:check says whether it has drifted since. 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, 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.
License
MIT © nolindnaidoo
