schema-define-fields SKILL.md skillA
schema-define-fields 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/schema-define-fields@git:20260924.c6e4810Pins git:20260924.c6e4810 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/schema-define-fields/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260924.c6e4810, committed Sep 24, 2026
- First version recorded
- Jul 7, 2026
- Size
- 9,465 bytes
- Repository stars
- 7
- License
- Apache-2.0
Add or define specific fields in a collection's readSchema. Use when fields are missing from materialization field selection, pruned by complexity limit, need type refinement, need to be protected from future inference changes, or need to be required for downstream consumers. Use when user says "missing fields", "pruned fields", "field not showing up", "complexity limit", "define field in read schema", "restrict field type", or "protect field from inference".
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
# Define Fields in the Read Schema Add or refine specific field definitions in a collection's readSchema. The readSchema controls what materializations and derivations see when reading from a collection. **Docs:** https://docs.estuary.dev/guides/customize-materialization-fields/#pruned-fields ## When to Use - **Pruned fields** — Fields missing from materialization field selection because schema inference hit `x-complexity-limit` (1,000 fields default, 10,000 per binding for captures that emit a `SourcedSchema` — most SQL captures, plus Salesforce-native, HubSpot-native, Kinesis, and other CDK connectors that opt in) - **Type refinement** — Inference saw bad data and widened a field's type (e.g., `[string, null, array]`); you want to narrow it to `[string, null]` for downstream consumers - **Define specific fields** — Ensure certain fields are always present and typed when materializations read the collection …
Read the whole file at its exact version.
How to install
mdr add estuary/agent-skills/schema-define-fields@sha256:3a27be54455dd5a1The line at the top of this page pins the label git:20260924.c6e4810, 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_rqkfnavj3df5erlu)
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Versions
The registry has recorded 2 versions of this file, between Jul 7, 2026 and Sep 24, 2026, about one every 79 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260924.c6e4810 latest | 2026-09-24 | c6e4810 | 9,465 B | A | view · diff |
| git:20260707.049f6ae | 2026-07-07 | 049f6ae | 9,479 B | A | view |
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 (9465 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_rqkfnavj3df5erlu GET https://markdownregistry.com/api/v1/resolve?ref=estuary/agent-skills/schema-define-fields GET https://markdownregistry.com/api/v1/blob/3a27be54455dd5a14dd0133489cfa383b881a1d32842d7af1d8d343f0aaf2c68
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.