Regex Explainer MCP server
online · 100% uptimeExplain a regex in plain English and detect catastrophic backtracking risk.
Little public usage data yet
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If you have run it, two minutes of your experience saves the next person an afternoon.
Regex Explainer tools (1)
write = sends, deletes, buys or postsexplain_regexFreeExplain a regular expression in plain English and detect the failure modes that make patterns dangerous rather than merely wrong. Use this whenever a regex needs to be read, reviewed, or verified — and ALWAYS before putting a pattern somewhere it will run against untrusted input. The critical check is catastrophic backtracking: a pattern like (a+)+$ is three characters longer than a safe equivalent, looks harmless, and takes minutes of CPU on a 30-character input that almost matches. That makes it a denial-of-service vector. Whether a pattern is vulnerable depends on whether nested quantifiers can match the same characters in more than one way, which is a structural property that is unreliable to judge by reading. It also flags: missing anchors (an unanchored validator accepts any string that merely CONTAINS a valid value), unescaped dots, character ranges like [A-z] that span punctuation, alternation precedence mistakes where an anchor applies to only one branch, and constructs JavaScript does not support. Input: `pattern` accepts either a bare pattern or a full /pattern/flags literal. JavaScript syntax; PCRE-only constructs are reported as unsupported rather than guessed at. Returns: `summary` (one sentence), `steps` (an ordered walkthrough), `warnings` (each with a code, severity, detail, and fix), `flagNotes`, capture group counts and names, and `hasBlockingIssue` — check that flag first. If the pattern cannot be parsed it returns an error naming the position, rather than a plausible-looking explanation of something else.
Public scan report
scanner v0.1.10 · 2026-10-16 · same rubric, same numbers if you re-run it
- –Code scanremote-only server, no package to scann/a
- Live reliabilityremote reachable in 1419ms20/20
- Tool poisoning1 tool descriptions checked15/15
- Auth qualityopen endpoint, read-only tools10/15
- Maintenancerepository not readable: repo not found3/15
- Maintainer identityendpoint served from the registry-verified namespace domain8/10
How Regex Explainer compares
Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.
- Safety score
- 75/100
- higher than 45% of 48,243 servers
- Tools
- 1
- the typical server has 7
- Tools that change things
- 0%
- typical: 0%. Fewer write tools means less an agent can break
- Uptime
- 100%
- of our recent checks; the typical remote server answers 100%
- Response time
- 138 ms
- faster than 77% of 30,027 servers
What its tools let an agent do: 1 read
Install Regex Explainer in Claude Code, Cursor or VS Code
claude mcp add --transport http regex-explainer https://regex-explainer.gumballtools.com/api/mcp
Grade history
- 2026-10-16restoreC → Bscore 75
Regex Explainer: common questions
- Is Regex Explainer MCP server safe?
- Mostly: it is graded B (75/100). Read the Regex Explainer safety report
- How do I install Regex Explainer?
- It runs remotely at regex-explainer.gumballtools.com. Add it to Claude Code, Cursor, VS Code or Claude Desktop with the snippets above, or call it through the mcp.market gateway without installing anything.
- Does Regex Explainer need an API key?
- Not as far as the registry entry and our scan can tell: no credentials are declared or required.
- Is Regex Explainer maintained?
- The latest release is v0.1.0.
- Is Regex Explainer up?
- 100% of our last 28 checks got an answer. We check remote servers about four times a day.
- How does Regex Explainer compare with other MCP servers?
- safety score 75/100 (higher than 45% of 48,243 servers); tools 1 (the typical server has 7); tools that change things 0% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.