schema-custom-types-ddl SKILL.md skillA
schema-custom-types-ddl 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-custom-types-ddl@git:20260707.049f6aePins git:20260707.049f6ae 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-custom-types-ddl/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260707.049f6ae, committed Jul 7, 2026
- Size
- 11,317 bytes
- Repository stars
- 7
- License
- Apache-2.0
Override default column types in materializations using castToString or custom DDL. Use when column type needs different precision (e.g., NUMERIC(22,6)), VARCHAR length is wrong, need JSONB instead of JSON, integers lose precision, or need to force a string representation. Use when user says "change column type", "wrong precision", "VARCHAR too short", "integer truncated", "cast to string", or "custom DDL".
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
# Custom Column Types
Override default column types in materializations using `castToString` or custom `DDL`.
**Docs:** https://docs.estuary.dev/guides/advanced-usage/custom-column-types/
## When to Use
- Integer overflow or `value out of range` on large IDs → `castToString` or `DDL: "NUMERIC(...)"`.
- Monetary values lose precision as `DOUBLE` → `DDL: "NUMERIC(22,6)"`.
- Multi-type unions (`[integer, null, string]`) mapped to JSON when you want a string → `castToString`.
- Need a specific destination type (e.g., `JSONB` instead of `JSON`, custom VARCHAR length).
## Two Options
### castToString — Convert to String (Simpler)
Converts the value to its string representation before writing — numbers become `"3"`, booleans `"true"`, objects stringified JSON. More robust than `DDL: "STRING"` because it actually transforms the data.
```yaml
fields:
recommended: true
require:
large_id: { castToString: true }
```
> Field configs go under `fields.require`. `include` is accepted as a legacy alias but is normalized to `require` on publish — if you write `include`, your next `pull-specs` will show `require`. Use `require` to avoid confusion.
…Read the whole file at its exact version.
How to install
mdr add estuary/agent-skills/schema-custom-types-ddl@sha256:d70bd203ce36f6deThe line at the top of this page pins the label git:20260707.049f6ae, 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_ccx3pyf3iukyqa3l)
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Versions
The registry has recorded 1 version of this file, committed on Jul 7, 2026.
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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_ccx3pyf3iukyqa3l GET https://markdownregistry.com/api/v1/resolve?ref=estuary/agent-skills/schema-custom-types-ddl GET https://markdownregistry.com/api/v1/blob/d70bd203ce36f6def56d5a987b295875e89c225baaec7ff871b50c326d4ce735
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.