---
id: MAN-7
family: GR-MAN
level: extended
profiles: [storage-api]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/gr-man/man-7
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# MAN-7 — Only a flat default is published

*GR-MAN (Part I) · level: extended · profiles: storage-api · added in 1.0*

A default is published so a caller knows what happens if they omit the input. Anything with nested structure is dropped rather than half-published, and the rest of the fragment survives the drop.

## The rule

> **Normative.** This is the rule.
>
> 1. A `default` survives into the published contract when it is null, a scalar, or a collection one level deep whose every member is null or a scalar, an empty collection included.
>
> 2. A default of any other shape, including one with a nested value, is dropped and the drop is logged.
>
> 3. Dropping a default never affects the rest of the fragment: every other contract key of that entry is retained.


## What it means

A default is published so a caller can know what happens without supplying
the input, and that only works if the published value is exactly what the
runtime would use. A scalar is always safe. A collection one level deep is
safe too, as long as every member of it is itself null or a scalar — a flat
list, or a flat map, both count. Anything deeper is dropped rather than
half-published, because a caller reading a truncated nested default would be
told the wrong thing with no way to notice.

Dropping a default touches nothing else: every other key of that entry's
contract fragment — its `type`, its `maxLength`, whatever else survived
MAN-5's strip — is retained exactly as it was.

## Example

```json title="A scalar default" verdict="retained"
{ "type": "string", "default": "abc" }
```

```json title="A one-level map whose members are scalar or null" verdict="retained"
{ "default": { "a": 1, "b": null } }
```

```json title="A default nested one level too deep" verdict="dropped"
{ "type": "array", "default": { "nested": { "too": "deep" } } }
```

The third default is gone from the published fragment, but its `type` key is
not:

```json title="What the third fragment publishes"
{ "type": "array", "x-data-type": "array" }
```

## Related rules

- Names: MAN-5
- Referenced by: MAN-5

---

Rule identifiers are permanent and are never renumbered. This specification carries
no implementation status: each implementation publishes its own standing against
these rules. Licensed CC BY 4.0.