---
id: MAN-17
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-17
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# MAN-17 — Declared outputs are collected by the same mapping, in reverse

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

The output side of the manifest, with one distinction that matters: a node that produced null produced something, and is not the same as a node that produced nothing.

## The rule

> **Normative.** This is the rule.
>
> 1. Each declared output name resolves to the result the bound node produced on the bound port.
>
> 2. Presence is decided by whether the key exists, so a null value counts as produced and is returned.
>
> 3. An output whose node produced nothing at all is dropped from the result with a warning.
>
> 4. A malformed output entry is skipped.


## What it means

Presence is decided by whether the key exists, not by whether the value is
truthy. A node that produced `null` on its bound port produced something,
and that null is returned under the declared output name. That is different
from a node whose bound port never appears in what it produced at all — that
case is dropped from the result, with a warning, because there is nothing to
return.

A malformed entry — one missing its name, its node id or its port — is
skipped without a warning: it never named a real output in the first place,
so there is nothing to warn about.

## Example

The workflow declares two outputs bound to the same node: `answer`, on its
`text` port, and `hidden`, on a `debug` port the node did not produce this
run.

```json title="What the bound node produced" verdict="retained"
{ "llm.1": { "text": null } }
```

```json title="The declared outputs resolved against it" verdict="retained"
{ "answer": null }
```

The `debug` port never appears in `llm.1`'s results at all, so `hidden` is
dropped from the outputs, with a warning naming it. A malformed entry — an empty name, an empty node id, or an empty port — is
skipped the same way, but without the warning the dropped case above gets.

## Related rules

- Names: MAN-8, MAN-11
- Referenced by: MAN-8, MAN-11

---

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.