estuary/agent-skills · skills/derivation-join-collections/SKILL.md

derivation-join-collections skillA

derivation-join-collections is agent-read markdown (skill) from estuary/agent-skills: Create an Estuary derivation that joins two or more collections on a shared key, merging their fields into a single enriched collection. Use for data enrichment, denormalisation, building wide tables for BI, and real-time CDC joins. Derivations add complexity and cost — confirm the user wants a derivation before reaching for this (a destination-side SQL join or BI tool view is often simpler). Use when user says "join-collections derivation", "derivation to join two collections", "transformation .

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add estuary/agent-skills/derivation-join-collections@git:20260707.6b608bf
Exact content
mdr add estuary/agent-skills/derivation-join-collections@sha256:030eae834df24a23

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

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[![mdr](https://markdownregistry.com/badge/art_l43gzrhiqm74pmxd.svg)](https://markdownregistry.com/a/art_l43gzrhiqm74pmxd)

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Versions

versioncommittedcommitsizeaudit
git:20260707.6b608bf latest2026-07-07 6b608bf 14,680 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (14680 bytes)
  • pass: No zero-width or bidi control characters
  • pass: No instruction hidden inside an HTML comment
  • pass: No link to an exfiltration or paste host
  • pass: No credential-shaped string
  • pass: No instruction to send local credentials anywhere
  • pass: No text hidden with inline styles
  • pass: No prompt-injection phrasing
  • pass: No curl or wget piped into a shell
  • pass: No recursive delete of root, home or parent
  • pass: No instruction to read or print local credentials
  • pass: No base64 blob over 200 characters
  • pass: No link to a raw IP address
  • pass: No script tag

Source

GitHub

estuary/agent-skills · 7 stars · license Apache-2.0 · pushed 2026-09-17 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_l43gzrhiqm74pmxd
GET https://markdownregistry.com/api/v1/resolve?ref=estuary/agent-skills/derivation-join-collections
GET https://markdownregistry.com/api/v1/blob/030eae834df24a2330baeb4e7ad27e6b3bb223bcaac0453aeaef5747b9b17f4f

Agents talk at modelranch.com: hand yours the instructions there and it joins the network that reads files like this one.