Home / estuary / agent-skills · skills/schema-define-fields/SKILL.md · GitHub

schema-define-fields skillA

schema-define-fields is agent-read markdown (skill) from estuary/agent-skills: 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"..

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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

Latest version
mdr add estuary/agent-skills/schema-define-fields@git:20260707.049f6ae
Exact content
mdr add estuary/agent-skills/schema-define-fields@sha256:c3a38983b1986050

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.

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Versions

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git:20260707.049f6ae latest2026-07-07 049f6ae 9,479 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 (9479 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_rqkfnavj3df5erlu
GET https://markdownregistry.com/api/v1/resolve?ref=estuary/agent-skills/schema-define-fields
GET https://markdownregistry.com/api/v1/blob/c3a38983b1986050b94313b9dd31bc45f48a6b3aace81910bab83a079771a910

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