Dataset Join & Merge
REMOTE · DATASET-JOIN-MERGE.NEROLABS.WORKERS.DEV · SCANNED SEP 20
Join two lists of JSON rows on a key, like SQL or VLOOKUP: left, inner, full, anti joins, union.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security46
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 2 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement. View diagnostics → Unverified
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability60
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 793 tokens (~396/item across 2 items; 2 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 Management23
- Stability observed for 7 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 2 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 3 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities60
- Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28. See how to fix → Fail
How do I install the Dataset Join & Merge MCP server?
Dataset Join & Merge is a hosted endpoint at https://dataset-join-merge.nerolabs.workers.dev/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · dataset-join-merge.nerolabs.workers.dev
claude mcp add --transport http nero-engine-dataset-join-merge 'https://dataset-join-merge.nerolabs.workers.dev/mcp'
{
"mcpServers": {
"nero-engine-dataset-join-merge": {
"url": "https://dataset-join-merge.nerolabs.workers.dev/mcp"
}
}
} {
"servers": {
"nero-engine-dataset-join-merge": {
"type": "http",
"url": "https://dataset-join-merge.nerolabs.workers.dev/mcp"
}
}
} [mcp_servers.nero-engine-dataset-join-merge] url = "https://dataset-join-merge.nerolabs.workers.dev/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"nero-engine-dataset-join-merge": {
"type": "remote",
"url": "https://dataset-join-merge.nerolabs.workers.dev/mcp",
"enabled": true
}
}
} openclaw mcp add nero-engine-dataset-join-merge --url 'https://dataset-join-merge.nerolabs.workers.dev/mcp' --transport streamable-http
mcp_servers:
nero-engine-dataset-join-merge:
url: "https://dataset-join-merge.nerolabs.workers.dev/mcp" {
"McpServers": {
"nero-engine-dataset-join-merge": {
"Transport": "http",
"Url": "https://dataset-join-merge.nerolabs.workers.dev/mcp"
}
}
} assistant mcp add nero-engine-dataset-join-merge -t streamable-http -u 'https://dataset-join-merge.nerolabs.workers.dev/mcp'
{
"mcpServers": {
"nero-engine-dataset-join-merge": {
"type": "http",
"url": "https://dataset-join-merge.nerolabs.workers.dev/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
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.
- 20 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.
- 18 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.
- 15 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.
- 14 Sept 26 0
- Stability: unverified → 0.03 ▲ functional
- 13 Sept 26 56
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 20 Sept 2026 · Probed https://dataset-join-merge.nerolabs.workers.dev/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=nerolabs.workers.dev | CN=YE2,O=Let's Encrypt,C=US | 12 Sept 2026 | 11 Dec 2026 | ECDSA 256 | ECDSA-SHA384 | 6f7f02a43942bb2aca3c411aec703cf0dc1 |
| SANs: *.nerolabs.workers.dev, nerolabs.workers.dev | ||||||
| CN=YE2,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 4df3b15dd6c0784c507cd37b58e6f115 |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of dataset-join-merge.nerolabs.workers.dev. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| dev. | present | 60074 | 8 | Verified |
| workers.dev. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://dataset-join-merge.nerolabs.workers.dev/mcp | Verified | 200 | |
| http (plaintext) | http://dataset-join-merge.nerolabs.workers.dev/mcp | Inconclusive | 405 |
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 →
join_rows ~687
Joins two lists of JSON rows on a shared key, like a SQL join or a spreadsheet VLOOKUP, and returns the combined rows plus a summary: how many rows matched on each side, match rates, and warnings for duplicate keys, rows missing the key and key fields that exist on no row. Use it to enrich a list with fields from a lookup table (left join), keep only the overlap (inner), combine two sources into one table (full), find rows in one list that are missing from the other (leftAnti or rightAnti), or stack two same-shape lists (union). Keys match case-insensitively with whitespace trimmed by default, and the key can have a different name on each side (email on the left, contact_email on the right). Input and output rows are capped per call; a many-to-many join that would exceed the output cap is refused with the predicted row count, never truncated. Call list_capabilities for the exact limits.
| Name | Type | Req | Description |
|---|---|---|---|
| includeJoinInfo | boolean | – | On by default: every row gets _joinStatus ("matched", "left_only", "right_only") and _matchCount. Set false for rows with only your own fields. |
| joinType | string | – | Which rows to keep. left (default): every left row, enriched where a match exists. inner: matched rows only. right: every right row. full: everything from both sides. leftAnti: left rows with no matc… |
| keyMatching | string | – | normalized (default): case-insensitive, trimmed, repeated spaces collapsed, 123 matches "123". exact: values must be identical. |
| leftKeyFields | array | – | The field name(s) on the left rows to match on, for example ["email"], or ["firstName","lastName"] for a composite key. Required for every joinType except union. |
| leftRows | array | yes | The LEFT table: the main rows you want to keep or enrich. Each row is a JSON object; keys may differ between rows. |
| multipleMatches | string | – | When one key matches several right rows. all (default): one output row per matching pair, like SQL. first: only the first matching right row, like VLOOKUP, so each left row appears once. |
| onFieldConflict | string | – | When a right field has the same name as a left field. prefixRight (default): keep both, the right one renamed with rightFieldPrefix. keepLeft: ignore the right value. keepRight: overwrite the left va… |
| rightFieldPrefix | string | – | Prefix for conflicting right fields when onFieldConflict is prefixRight. Default "right_", so price becomes right_price. |
| rightFields | array | – | Only copy these fields from the matching right row, like choosing VLOOKUP return columns. Leave out to copy every right field. |
| rightKeyFields | array | – | The matching field name(s) on the right rows, in the same order as leftKeyFields, for example ["contact_email"]. Leave out when the right rows use the same names as the left. |
| rightRows | array | yes | The RIGHT table: the lookup rows to pull matching fields from. Each row is a JSON object. |
No output schema declared.
No examples provided.
list_capabilities ~52
Returns every join type, key matching mode, conflict strategy and fan-out mode this server supports, the fields it adds to each row, and the input and output row limits per call. Free, processes no data.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
What is the Dataset Join & Merge MCP server?
Dataset Join & Merge is an MCP server listed in the public MCP registry as io.github.Nero-Engine/dataset-join-merge. Join two lists of JSON rows on a key, like SQL or VLOOKUP: left, inner, full, anti joins, union. This page covers its hosted endpoint (https://dataset-join-merge.nerolabs.workers.dev/mcp).
Is the Dataset Join & Merge MCP server safe to use?
Dataset Join & Merge scores 59 out of 100 on VerifyMCP. 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 Dataset Join & Merge MCP server expose?
Dataset Join & Merge exposes 2 tools: list_capabilities, join_rows. Their descriptions and schemas cost roughly 739 tokens of context every time the server is loaded.
Does the Dataset Join & Merge MCP server require authentication?
No. We connected to Dataset Join & Merge without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Dataset Join & Merge MCP server still maintained?
Dataset Join & Merge is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.