---
id: ERR-13
family: RT-ERR
level: core
profiles: [runtime]
posture: normative-target
added: "1.0"
changed: "1.0"
source: https://flowdrop.io/spec/rules/rt-err/err-13
specification: FlowDrop Workflow Specification 1.0-draft
licence: CC BY 4.0
---

# ERR-13 — Every execution strategy routes errors identically

*RT-ERR (Part II) · level: core · profiles: runtime · added in 1.0*

A workflow that handles its own failures must mean the same thing whichever engine runs it, including the direct synchronous one.

## The rule

> **Normative.** This is the rule.
>
> 1. All execution strategies route error outputs the same way.
>
> 2. Where the failing node has an error edge, its outputs are replaced by the shared error envelope and the run continues; where it has none, the run fails.
>
> 3. No strategy may substitute its own error-handling behaviour.


## What it means

The contract holds even for the strategy with the least machinery behind it.
A strategy that runs a workflow in one pass, with nothing persisted between
steps, still owes the same envelope a strategy built around persisted steps
delivers: the same four keys, in the same shape, to the same downstream
input. Having no step record to carry the envelope in is not a reason to
carry less of it, or to shape it differently because the surrounding
machinery differs. Nothing about how a strategy is built earns it its own
error-handling behaviour.

## Example

A node with a wired error edge fails under the strategy that keeps no record
between steps; the downstream node's input arrives exactly as it would under
any other strategy.

```json title="What the downstream node's input port receives" verdict="routed"
{"message": "boom blew up", "code": "E42", "node_id": "boom", "retryable": false}
```

## Why

Recorded under OPEN-1.

## Related rules

- Names: ERR-7, ERR-8
- Referenced by: ERR-7, ERR-12

---

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.