derivation-filter-transform SKILL.md skillA
derivation-filter-transform from estuary/agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add estuary/agent-skills/derivation-filter-transform@git:20260707.6b608bfPins git:20260707.6b608bf in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- estuary/agent-skills
- Path
skills/derivation-filter-transform/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260707.6b608bf, committed Jul 7, 2026
- Size
- 12,701 bytes
- Repository stars
- 7
- License
- Apache-2.0
Create an Estuary derivation for stateless filtering, field selection, and per-document field transformation. Use for WHERE clauses, projecting fields, computing new fields from existing ones, or data cleansing. Derivations add complexity and cost — confirm the user wants a derivation before reaching for this (renaming alone is usually a projection, not a derivation). Use when user says "filter-transform derivation", "derivation to filter by status", "transformation with WHERE clause…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# derivation-filter-transform Stateless Estuary derivation that filters documents and/or transforms field values. Each source document produces zero or one output document; no state, no cross-document coordination. **Prereq:** read `derivation-basics` first for concepts, project layout, workflow, and language choice. ## When to use this over alternatives - **Filtering** (`WHERE` clause): drop documents that don't match criteria - **Computed fields**: derive new fields from existing ones (`CASE`, arithmetic, string manipulation, lookups) - **Data cleansing**: normalise formats, trim whitespace, replace nulls - **Selecting a subset of fields** when combined with the above For a plain rename or nested-field flattening with no computation, use `schema-projections` — a projection doesn't require a derivation task. ## Canonical Example — SQL Cleanse a `customers` collection for downstream analytics: drop inactive accounts and those with obviously invalid emails, normalise the email, and compute a `tier` bucket from lifetime spend. ### `schema.yaml` …
Read the whole file at its exact version.
How to install
mdr add estuary/agent-skills/derivation-filter-transform@sha256:5b84c740970d0168The line at the top of this page pins the label git:20260707.6b608bf, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_r6lmexivq3ijyva6)
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Versions
The registry has recorded 1 version of this file, committed on Jul 7, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (12701 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
estuary/agent-skills · 7 stars · license Apache-2.0 · pushed 2026-11-04 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_r6lmexivq3ijyva6 GET https://markdownregistry.com/api/v1/resolve?ref=estuary/agent-skills/derivation-filter-transform GET https://markdownregistry.com/api/v1/blob/5b84c740970d01685744e2861de9ec34966af724e7d7f340b51c3153c1e22911
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.