Versions-LE: Two Pins, One Dependency

Find where one dependency is constrained differently across a repository's manifests — and where no version can satisfy both
package.json · Cargo.toml · pyproject.toml · go.mod · GitHub workflows

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What it does

The build broke because api asks for regex = "1" and web asks for regex = "2", and no one version satisfies both. Or it did not break, and will: CI has built on Rust 1.80 since March while rust-version says 1.88.

Press Ctrl+Alt+V (Cmd+Alt+V on Mac) and every manifest in the workspace is compared as one set — or every manifest under a folder, from the Explorer. The report opens beside the editor: each problem by severity with every file, key and constraint that produced it, then what was deliberately not compared and why. Works in VS Code and in VS Code–based editors like Cursor and VSCodium (installable from Open VSX).

• In a monorepo — the crate pinned to serde 0.9 while the rest moved to 1.0
• Before a release — CI testing on a toolchain older than the minimum you publish
• Reviewing a dependency bump — the one package that did not move with the others

It never edits a manifest, and never guesses: a constraint it does not model is named and left out of every comparison.

Install

The six checks

Different and unsatisfiable are two findings. constraint-conflict is a smell; disjoint-constraint is a build that cannot resolve. They are never conflated.

Disjointness is decided by interval arithmetic over the modelled ranges, not by string comparison — which is also why >=20 and >=20.0.0 are not reported as a conflict. They are one requirement typed twice.

One finding per drifted dependency, carrying every site. A dependency constrained four ways is one problem with four sites, and four findings would read as four problems.

The four refusals

It never guesses. A constraint in a grammar this tool does not model is named in the report's refusals and takes part in no comparison — never approximated into a range.

malformed-constraint is a finding, not a refusal, and the difference is deliberate: it is the narrower verdict that the value is shaped like a constraint of its own ecosystem and is broken. The tool blames the manifest only when it is sure; everything else it blames on itself. ^^1.0.0 is malformed. latest is not — it is a syntax with a meaning this tool chose not to model.

Comparison never crosses an ecosystem. An npm semver and a Cargo semver are unrelated packages that share a word — and a bare "1.0.200" means exactly 1.0.200 in npm and anything below 2.0.0 in Cargo. One bridge exists, msrv-mismatch, and it is built by naming both keys rather than by matching a name.

What it reads

That last row is why this exists as much as the first: a CI toolchain drifting away from the floor a manifest declares is exactly the failure nobody notices until a release.

node_modules, vendor and .git are never read. .github always is — a workflow lives in a hidden directory by definition.

What it will not do

• It never edits a manifest. No --fix, no --pin, no --update. The right version for a drifted dependency is a decision, not a derivation.
• It never resolves a dependency graph. It reads what the manifests say, not what a resolver would pick — no lockfiles, no transitive analysis.
• It never hits the network. It does not know which versions exist, which are yanked, or which are newest; only whether two stated requirements can be met at once.
• It does not lint style. Ordering, quoting and formatting of a manifest are somebody else's job.

Use it from an AI agent

The same engine runs as an MCP server, so an agent can call it directly instead of diffing manifests by eye.

compare_versions(files: [{ path, content }], maxResults?)

It returns the report the editor renders, as data — findings capped at 500 by default with meta.truncated. It reads no files and makes no network requests. Published as versions-le-mcp on npm and as io.github.nolindnaidoo/versions-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 manifest sets — broken JSON and TOML included — and compares every answer.

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

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

The CLI

The same comparison 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 constraint differently.

versions-le .                          # every manifest in the tree, as one JSON report
versions-le --ecosystem cargo .        # one ecosystem
versions-le --fail-on any .            # floating pins fail the build too
versions-le --strict .                 # an unanalysed corner exits 2
versions-le mcp                        # compare_versions and versions_le_check over MCP on stdio

The exit code is the product — 0 nothing above info, 1 findings, 2 the question was malformed. No manifests at all is 0: nothing can conflict with nothing.

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 finding's message is the engine's English, identical to the CLI's.

Privacy & security

• No network access. The extension never sends data anywhere; it does not know which versions exist, only whether two stated requirements can be met at once. The telemetryEnabled setting only writes events to a local Output Channel you can inspect (Versions-LE).
• It reads manifests and nothing else, and never writes to one.
• 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

265 test cases across 13 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