ANTHROPIC_FOUNDRY_API_KEY
A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.138, including the newest one read.
What it is
API key for Microsoft Foundry authentication (see [Microsoft Foundry](/docs/en/microsoft-foundry))
Anthropic's own wording. Read off Environment variables, captured 2026-08-28.
Presence across releases
| Releases | Reading | Declared type | Default |
|---|---|---|---|
| 2.1.245 – 2.1.250 5 releases | never mined | — | — |
| 2.1.160 – 2.1.243 75 releases | in the build | str | — |
| 2.1.138 – 2.1.159 20 releases | in the build | — | — |
A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.
Changelog entries naming it
No changelog entry here has ever named it. That is a statement about what has been written, not about the name: it has been in the build since v2.1.138 without anybody writing a line about it.
Documentation pages
- Environment variables reference table Claude Code CLI
- claude-in-microsoft-foundry mentions it Claude Developer Platform
- Connect Claude Code to an LLM gateway mentions it Claude Code CLI
- Claude Code on Microsoft Foundry mentions it Claude Code CLI
- Troubleshoot installation and login mentions it Claude Code CLI
A reference table page is one whose own table defines this name, and it is where the description above came from. A page that mentions it carries the name somewhere in its text and may say nothing about it at all. Every page carrying it.
Names beside it
Every environment variable in the inventory starting anthropic_foundry, up to twelve of them.
ANTHROPIC_FOUNDRY_AUTH_TOKENBearer token for Microsoft Foundry authentication, such as a Microsoft Entra access token. Claude Code sends it as the Authorization: Bearer header. Takes precedence over ANTHROPIC_FOUNDRY_API_KEY and over the Azure default credential chain. See [Microsoft Foundry](/docs/en/microsoft-foundry). Requires Claude Code v2.1.203 or later 2.1.203
ANTHROPIC_FOUNDRY_BASE_URLFull base URL for the Microsoft Foundry resource (for example, https://my-resource.services.ai.azure.com/anthropic). Alternative to ANTHROPIC_FOUNDRY_RESOURCE (see [Microsoft Foundry](/docs/en/microsoft-foundry)) 2.1.138
ANTHROPIC_FOUNDRY_RESOURCEMicrosoft Foundry resource name (for example, my-resource). Required if ANTHROPIC_FOUNDRY_BASE_URL is not set (see [Microsoft Foundry](/docs/en/microsoft-foundry)) 2.1.138
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the environment variable does. All environment variables.