The same call from PowerShell

Put the key in the environment

Open PowerShell (Windows PowerShell 5.1 or PowerShell 7 both work). This prompts for the key without showing it and keeps it for this window only:

$secure = Read-Host "Paste your OpenAI key" -AsSecureString
$env:OPENAI_API_KEY = [System.Net.NetworkCredential]::new("", $secure).Password

Close the window and the key is gone. OpenAI's quickstart also shows setx OPENAI_API_KEY "...", which saves the key for every future window (OpenAI quickstart). That is convenient, but it types the key on a command line (so it lands in PowerShell's history file) and leaves it stored in your Windows profile. While you are learning, the prompt above is the safer habit. Microsoft documents how the three scopes (this window, your user, the whole machine) work in about Environment Variables.

One call

Build the body as a PowerShell object and let PowerShell write the JSON. That sidesteps every quoting problem at once.

$body = @{
    model             = "gpt-6-astra"
    max_output_tokens = 300
    input             = "Rewrite as one plain sentence: the meeting is moved to Thursday."
} | ConvertTo-Json -Depth 6

$reply = Invoke-RestMethod -Uri "https://api.openai.com/v1/responses" -Method Post `
    -Headers @{ Authorization = "Bearer $env:OPENAI_API_KEY" } `
    -ContentType "application/json; charset=utf-8" `
    -Body ([System.Text.Encoding]::UTF8.GetBytes($body))

($reply.output | Where-Object type -eq "message").content.text
$reply.usage

Invoke-RestMethod turns the JSON reply into an object, so you read fields with dots instead of parsing text (Invoke-RestMethod). The last two lines print the answer and the token counts. For Anthropic, change the address, send x-api-key and anthropic-version headers, put the text in messages, and read $reply.content.text.

Save the output

Save both the answer and the whole reply. The answer is what you use; the full reply is what you check when something looks wrong.

New-Item -ItemType Directory -Path .\out -Force | Out-Null
($reply.output | Where-Object type -eq "message").content.text |
    Set-Content -Path .\out\answer.txt -Encoding utf8
$reply | ConvertTo-Json -Depth 20 | Set-Content -Path .\out\reply.json -Encoding utf8

-Encoding utf8 matters in Windows PowerShell 5.1, which otherwise writes some files in an older encoding that mangles curly quotes and accented names.

Four things that trip Windows users

When a call fails, Invoke-RestMethod throws, and the vendor's error message is in the exception, not on the screen. This shows it:

try { Invoke-RestMethod ... } catch { $_.ErrorDetails.Message }

Put your call where the three dots are. A 401 means the key variable is empty or wrong in this window; $env:OPENAI_API_KEY.Length prints its length without showing it.

What to do with this

Send the call above, open out\reply.json, and find the usage block. Then take the same pattern to the recipes, which run the same way from Python on Windows.

Vendor facts checked 25 Sep 2026; re-verify before relying on them.