Regex Lab
OCI · GHCR.IO/BASITALISANDHU/MCP-REGEX-LAB
Test regular expressions in a timeout-guarded worker, explain them, find catastrophic backtracking.
Available components
Last scanned (21 hours ago)
Scores higher than 71% of OCI servers
Category Testing and QA
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security0
- No malware scan is available for this kind of package: the supply-chain vendors we use do not cover it. This is a permanent gap in our coverage, not a finding about the package.Unverified
- Known CVEs could not be checked: this artifact ships no SBOM or dependency manifest, so there is no dependency list to read.Unverified
- Install-script risk not yet assessed.Unverified
- Dependency health could not be checked: this artifact ships no SBOM or dependency manifest, so there is no dependency list to read.Unverified
Provenance & Transparency100
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Cryptographically verified build provenance (signed, bound to basitalisandhu/dev-mcp-servers). View diagnostics → Pass
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 2 days ago).Pass
- Publishes a security disclosure policy (SECURITY.md).Pass
Schema Quality & AI Usability60
- AI-judged instruction clarity (good).Pass
- Context-footprint check failed: tool/resource definitions use about 672 tokens (~224/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management0
- Stability not yet verified: not enough scan history yet (needs a 30-day window).Unverified
Tool Coverage91
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 73% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Unverified: 2 categories
Categories scored 0 because we could not verify them: a data source with nothing on this package, evidence we could not reach, or a check we could not run. We only credit what we can confirm.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 14 Oct 26 +28
- Injection markers: unverified → pass ▲ security
- First check of Judged manipulation: pass security
- Stability: Stability not yet verified: not enough scan history yet (needs a 30-day window). security
- Tool coverage: unverified → 100 ▲ functional
- MCP protocol: unverified → pass ▲ functional
- First check of Schema quality: fail functional
- First check of Destructive annotations: pass functional
- First check of Schema quality: fail functional
- First check of Schema quality: good functional
- First check of Tool coverage: 73 functional
- 13 Oct 26 0
- Package version: 0.2.0 → 0.2.1 functional
- 12 Oct 26 0
- Package version: 0.1.1 → 0.2.0 functional
- 7 Oct 26 20
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 16 Oct 2026 · Analysed oci/ghcr.io/basitalisandhu/mcp-regex-lab@0.2.1
Provenance Verified
A signed build attestation was found and verified, binding this exact artifact to the source repository it claims to come from.
| Result | Verified |
|---|---|
| Ecosystem | oci |
| Reason | Verified |
| Discovered via | OCI referrers API |
| Source repo | basitalisandhu/dev-mcp-servers |
| Certificate issuer | https://token.actions.githubusercontent.com |
| Certificate SAN | https://github.com/basitalisandhu/dev-mcp-servers/.github/workflows/publish-github-packages.yml@refs/tags/v0.2.1 |
| Rekor log index | 3244679674 |
| Predicate type | SLSA build provenance https://slsa.dev/provenance/v1 |
| Subject digest | sha256:11b1b8d43e9be95c20bcb4daf95f9fbd287cb000a809732e61172712c0f01274 |
Background: How many MCP packages publish verified provenance →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
check_redos Check a regex for catastrophic backtracking ~247
Statically look for the constructs that cause exponential or polynomial backtracking: an unbounded repeat nested inside another (such as (a+)+ or (\d+\s?)*), alternatives that can match the same text inside a repeated group (such as (a|ab)*), and consecutive repeats that accept the same characters (such as \d+\d+). Each finding names the construct, a severity (high: likely exponential; medium: polynomial or needs review) and a character that exercises it. With probe (default true), the pattern is then timed in a worker against crafted non-matching inputs of growing length (from the probe character) and the timings are returned; the worker is terminated after timeout_ms (default 2000). No findings and flat timings is good evidence, not a proof, that the pattern is safe.
| Name | Type | Req | Description |
|---|---|---|---|
| flags | string | – | RegExp flags such as i, m, s, u. g and d are added automatically when matching. |
| pattern | string | yes | JavaScript regular expression source, without the surrounding slashes. |
| probe | boolean | – | Time the pattern against crafted inputs. Default true. |
| timeout_ms | integer | – | – |
No output schema declared.
No examples provided.
explain_regex Explain a regex ~125
Parse a pattern and describe it construct by construct: literals, character classes, escapes, anchors, groups (capturing, named, non-capturing, lookaround), quantifiers (greedy and lazy) and alternation, as indented lines plus the number of capturing groups. Reports a syntax error with its position when the pattern does not parse.
| Name | Type | Req | Description |
|---|---|---|---|
| flags | string | – | RegExp flags such as i, m, s, u. g and d are added automatically when matching. |
| pattern | string | yes | JavaScript regular expression source, without the surrounding slashes. |
No output schema declared.
No examples provided.
test_regex Test a regex against samples ~201
Run a pattern against up to 50 sample strings (each up to 20000 characters) and return every match with its start and end offsets, matched text, numbered and named capture groups with their offsets, and optionally the result of String.prototype.replace with the given replacement. Execution runs in a worker thread and is stopped after timeout_ms (default 2000, max 10000); results for samples finished before the timeout are still returned. At most 200 matches per sample are listed.
| Name | Type | Req | Description |
|---|---|---|---|
| flags | string | – | RegExp flags such as i, m, s, u. g and d are added automatically when matching. |
| pattern | string | yes | JavaScript regular expression source, without the surrounding slashes. |
| replacement | string | – | If given, each sample is also shown after replace(pattern, replacement); $1 and $<name> work as in JavaScript. |
| samples | array | yes | – |
| timeout_ms | integer | – | – |
No output schema declared.
No examples provided.
How do I install the Regex Lab MCP server?
Regex Lab runs locally as a container image, launched with docker run --rm -i ghcr.io/basitalisandhu/mcp-regex-lab:0.2.1. Ready-made configuration for Claude, Cursor, VS Code, Codex and 3 more is on this page, copied from each client's own documentation.
oci · ghcr.io/basitalisandhu/mcp-regex-lab
claude mcp add basitalisandhu-mcp-regex-lab -- docker run --rm -i ghcr.io/basitalisandhu/mcp-regex-lab:0.2.1
What is the Regex Lab MCP server?
Regex Lab is an MCP server listed in the public MCP registry as io.github.basitalisandhu/mcp-regex-lab. Test regular expressions in a timeout-guarded worker, explain them, find catastrophic backtracking. This page covers its container image (ghcr.io/basitalisandhu/mcp-regex-lab).
Is the Regex Lab MCP server safe to use?
Regex Lab scores 48 out of 100 on VerifyMCP. Its build provenance is signed and verified. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Regex Lab MCP server expose?
Regex Lab exposes 3 tools: test_regex, explain_regex, check_redos. Their descriptions and schemas cost roughly 573 tokens of context every time the server is loaded.
Is the Regex Lab MCP server still maintained?
Regex Lab is still listed as active in the MCP registry. We last reached this channel on 16 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the Regex Lab MCP server under?
Regex Lab declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.