# Dataset Join & Merge

> Join two lists of JSON rows on a key, like SQL or VLOOKUP: left, inner, full, anti joins, union.

- name: io.github.Nero-Engine/dataset-join-merge
- version: 0.1.0
- connection class: R0 (autonomous)
- trust: 94/100
- quality: 79/100 (good)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/io.github.Nero-Engine%2Fdataset-join-merge
- tools: https://api.protogrid.dev/v1/servers/io.github.Nero-Engine%2Fdataset-join-merge/tools

**An agent can connect right now, no human step.** Remote endpoint, no authentication, reachable on the last probe.

## Connection (mcpServers)

```json
{
  "mcpServers": {
    "dataset-join-merge": {
      "type": "http",
      "url": "https://dataset-join-merge.nerolabs.workers.dev/mcp"
    }
  }
}
```


## Trust

- hygiene: 100
- liveness: 99
- freshness: 85
- provenance: 90
- drivers: +repository +namespace-matches-repo +website +reachable +uptime-96% ~updated-38d-ago
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 79/100 (good)

### protocol: 75 (weight 25)

- warn `protocol.modern`: newest supported version is 2025-06-18; 2026-07-28 not supported, older versions are deprecated until 2027-07-28
- n/a `protocol.stateless`: only applies to 2026-07-28 servers
- pass `protocol.transport`: streamable HTTP
- n/a `protocol.list_ttl`: only applies to 2026-07-28 servers

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 71 (weight 30)

- pass `tools.descriptions`: every tool has a description
- pass `tools.description_length`: descriptions are concise
- pass `tools.schemas`: every tool has an object input schema
- fail `tools.annotations`: no tool declares readOnlyHint or destructiveHint, so clients cannot tell safe calls from risky ones
- fail `tools.directory_hints`: no tool declares all four of readOnlyHint, destructiveHint, idempotentHint and openWorldHint; missing: join_rows (readOnlyHint, destructiveHint, idempotentHint, openWorldHint); list_capabilities (readOnlyHint, destructiveHint, idempotentHint, openWorldHint)
- pass `tools.token_cost`: about 977 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump

### stability: 100 (weight 15)

- pass `stability.changes`: no tool changes in 30 days
- pass `stability.rug_pull`: no tool changed its meaning under the same name

### dependencies: n/a (weight 15)

- n/a `deps.known_vulns`, `deps.mcp_sdk_version`, `deps.resolvable`: no npm or PyPI package

- tools: 2, about 977 tokens to load them all
- tool set hash: 64e80d480a5f7d98bc2dcca4c619dab1
- badge: [![protogrid quality](https://protogrid.dev/badge/io.github.Nero-Engine/dataset-join-merge.svg)](https://protogrid.dev/servers/io.github.Nero-Engine/dataset-join-merge)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

_No tool definition changes recorded._

## Remotes

- https://dataset-join-merge.nerolabs.workers.dev/mcp (streamable-http, auth none, reachable true, uptime30d 0.9649123)

## Packages

_none_

## Tools (2)

- `join_rows`: 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.
- `list_capabilities`: 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.