Units-LE: One Quantity, One Unit

Find every quantity in a document — durations, sizes, percentages, frequencies — with its value in one base unit, and refuse the ambiguous ones by name
YAML · TOML · JSON · INI · dotenv · CSV · and anything else, scanned as text

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

What it does

timeout: 30s in one service and timeout: 30000 in another are the same number of milliseconds, and nothing about the text says so. memory: 1GB and memory: 1GiB differ by 7% and look identical at a glance.

Press Ctrl+Alt+Q (Cmd+Alt+Q on Mac) and every quantity in the active document — a number welded to a unit — opens in a report beside the editor: as the document wrote it, in one base unit so two of them can be compared, with its line, column and key path. A quantity it cannot read unambiguously keeps its row and gets a reason instead of a guess. Works in VS Code and in VS Code–based editors like Cursor and VSCodium (installable from Open VSX).

• Before a migration — every timeout and memory limit in a values file, in milliseconds and bytes
• Reviewing a config change — the 500m that means minutes to one reader and millicores to another
• Against a runbook or a retention policy — the limit the document states, checked against the one the config sets

It never rewrites a document, and never guesses.

Install

A refusal is a finding

This is the whole product. Any tool can multiply 30s by a thousand; what makes this one usable in a review is that it will not pretend.

Every one of them keeps its row, its source text, its position and a sentence a person can act on. A refusal is never a dropped row and never a guess.

si_iec_hazard annotates; it does not withhold

It is the one reason that still answers. MB is 10^6 by the standard, so 1MB comes back as 1000000 bytes and carries reason: "si_iec_hazard" — because a great deal of software writes MB and means 2^20. Reporting nothing would be less useful than reporting the standard answer with the flag attached, and picking 2^20 would be the guess this tool exists not to make.

So it is not counted as refused. A row with si_iec_hazard is the only row that carries both a base and a reason; every other reason means the base is null.

A bare number with no unit is not a finding at all. timeout: 30 yields nothing here — that is numbers-le's question, and the boundary is what keeps the two tools distinct.

Four dimensions

Case is part of the symbol. MB is a megabyte and Mb is a megabit; folding them would silently multiply by eight, so Mb is refused rather than treated as a synonym.

1h30m is a grammar and 1h + 30m is arithmetic. The first is one quantity written in two parts. Inside a compound the parts disambiguate each other — m alone is refused, and m between h and s can only be minutes, because a compound is written largest-first. That ordering is required rather than assumed, so 30s1h is not a quantity at all.

Physical units are a non-goal, not a gap. Length, mass, temperature belong to a different question, and reading them would mean unit algebra (m/s²), which is what uom is for. See crate/SPEC.md.

Formats

JSON, YAML, CSV, TOML, INI and dotenv are parsed. Everything else is scanned as text — a Kubernetes manifest, a Terraform file, a Markdown table of limits, a log — so the files where quantities actually live yield them rather than nothing.

Unlike numbers-le's text scan, this one has a shape to look for, so v1.2.3 yields nothing rather than two numbers. Every format with a shape carries a key path — cache.ttl, limits[0], server.timeout, TIMEOUT — and every finding carries a 1-based line and column, the column in UTF-16 units, which is the number your editor shows.

Its false-positive class is measured rather than imagined. A run inside an opaque blob still reads as a quantity: 001d in a UUID is one day, and a base64 hash ending /2w== is two weeks. The boundary characters that let those through are the same ones that let -30s and ttl=30s through. Over crate/fixtures/documents/opaque.txt — 280 lines of lockfile hashes, container digests, git object names, UUIDs and signing material, none of which is a quantity — the scan reports 5 false findings, 1.8%, and a test prints that number on every run. Each one carries its line and column, which is what makes it a row you discard rather than a number you trust.

It has no opinions

No "this timeout is too low". No defaults database. No conversion flag, no rewriting, no arithmetic. It reports what a document says and what that means in one base unit; which limits are right is the reviewer's call.

Use it from an AI agent

The same engine runs as an MCP server, so an agent can read quantities directly instead of converting units by hand.

extract_units(content, format?, filename?, dimension?, maxResults?)

It returns the report the editor renders, as data — quantities capped at 500 by default with meta.truncated. It reads no files and makes no network requests. Published as units-le-mcp on npm and as io.github.nolindnaidoo/units-le in the MCP registry. It answers exactly as the Rust CLI's server does: one corpus runs against both, and a differential test feeds both thousands of generated documents in every format — broken ones included, so each parser's error text is compared too.

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

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

The CLI

The same extraction runs over a tree from a terminal or a CI step: a Rust CLI in crate/, sharing one corpus with the extension — crate/fixtures/ — so the two can never read a quantity differently.

units-le .                                 # every quantity in the tree, one JSON report per file
units-le --dimension duration config/      # only the timeouts
units-le --strict config/                  # exit 2 if anything was refused
cat values.yaml | units-le --stdin --format yaml
units-le mcp                               # extract_units and units_le_scan over MCP on stdio

Exit codes follow grep — 0 quantities found, 1 none found, 2 the question was malformed. A refusal does not change the exit code; --strict makes it one.

Commands

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 and the report's headings). A refusal's sentence and a parser's error are the engine's English, identical to the CLI's.

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 (Units-LE).
• It reads the active document and nothing else, and never writes to it.
• The MCP server holds the same line. It takes content as an argument and returns data: no filesystem access, no network calls, no telemetry.
• Error notifications redact home directories and credential-shaped fragments.

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

531 test cases across 11 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