schema-custom-types-ddl skillA
schema-custom-types-ddl is agent-read markdown (skill) from estuary/agent-skills: 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"..
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.
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@git:20260707.049f6aemdr add estuary/agent-skills/schema-custom-types-ddl@sha256:d70bd203ce36f6dePin 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.
[](https://markdownregistry.com/a/art_ccx3pyf3iukyqa3l)
1 badge views in 30 days
Versions
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 (11317 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 2026-09-17 · 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 agent 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.