Run Octopus Deploy Runbook - 400 Bad Request when using fixed package versions

[Assura-Mark]

Step template

Run Octopus Deploy Runbook

Step version

18

Octopus version

2026.2 (Build 8245)

Step template parameter inputs

N/A for this issue.

What happened

I get the following error message in the log when running the runbook.

Invoking POST https://***/run/v1 
NotSpecified: Error calling https://***/run/v1 Response status code does not indicate success: 400 (Bad Request). StatusCode: BadRequest.

If I modify the script to include the actual error message from the API I get:

Error response:  
{ 
  "ErrorMessage": "There was a problem with your request.", 
  "Errors": [ 
    "A package version was specified for the step \u0027Run Create-PortableConfiguration.ps1\u0027, but the package has a version set on the step" 
  ], 
  "ParsedHelpLinks": [], 
  "Details": {} 
} 

Reproduction steps

Run a runbook that has packages with a fixed version - it should generate a 400 Bad Request response. The CLI does the same thing if you try run a runbook with a fixed package version.

More Information

I suspect that it's this function:

function Get-RunbookPackages
{
    param(
        $snapshotTemplate,
        $octopusUrl,
        $apiKey,
        $spaceId,
        $usingCaC
    )

    $runbookPackages = @()
    foreach ($package in $snapshotTemplate.Packages)
    {
        $packageVersion = Invoke-OctopusApi -octopusUrl $octopusUrl -apiKey $apiKey -spaceId $spaceId -endPoint "feeds/$($package.FeedId)/packages/versions?packageId=$($package.PackageId)&take=1" -method "Get" -item $null

        if ($packageVersion.TotalResults -le 0)
        {
            Write-Error "Unable to find a package version for $($package.PackageId).  This is required to create a new unpublished snapshot.  Exiting."
            exit 1
        }

        $runbookPackages += @{
            StepName = $package.StepName
            ActionName = $package.ActionName
            Version = $packageVersion.Items[0].Version
            PackageReferenceName = $package.PackageReferenceName
        }
        
    }

    return $runbookPackages
}

I think it needs a check that the FixedVersion is not null. I'm going to try and test a change on my system and see if it fixes it - but I'm not sure on the PR process so no promises there.

---

A couple of other minor things I've spotted:

• In Get-RunbookFormValues there's a line Write-OctopusInformation "Comparing $nameToSearchFor with provided prompted variable $($promptedValue[0])"``. This outputs only the first letter - I suspect this should be Write-OctopusInformation "Comparing $nameToSearchFor with provided prompted variable $($splitValue[0])"` which then outputs the whole name of the prompted variable.
• In the catch block for Invoke-OctopusApi I added Error response: rn$($_.ErrorDetails.Message)" to the end of the Write-Error outputs, which provided the raw response back from the API and was quite useful in tracking what happened. There's probably a cleaner approach to it than spitting out the raw JSON but I thought I'd mention it.