Microsoft Azure AI Foundry

Anthropic models served through Microsoft Azure AI Foundry (formerly Azure AI Studio).

Not to be confused with TrueFoundry. Microsoft Azure AI Foundry and TrueFoundry are different products with overlapping names. TrueFoundry → docs/profiles/truefoundry.md.

Quick start

agents harness create
# pick foundry, fill prompts, run smoke test
agents run my-profile "hello"

Required values

Var	Where to get it
Resource name	The Foundry resource name in the Azure portal (the prefix in <resource>.services.ai.azure.com)
API key	Azure portal → your Foundry resource → Keys and Endpoint
Model deployment id	Foundry → Deployments — must be a Claude deployment

Generated profile shape

name: my-profile
host: { agent: claude }
env:
  # static vars (always set):
  CLAUDE_CODE_USE_FOUNDRY: "1"
  # vars wizard collects:
  ANTHROPIC_BASE_URL: https://<resource>.services.ai.azure.com/anthropic
  ANTHROPIC_MODEL: claude-sonnet-4-5
  ANTHROPIC_SMALL_FAST_MODEL: claude-haiku-4-5
auth:
  envVar: ANTHROPIC_AUTH_TOKEN
  keychainItem: agents-cli.foundry.token

The base URL pattern is <resource>.services.ai.azure.com/anthropic — note the /anthropic suffix that routes to the Anthropic-shaped endpoint.

Known caveats

Foundry env vars intermittently ignored. Known issue claude-code#11937 — in some Claude Code releases CLAUDE_CODE_USE_FOUNDRY=1 is not consistently honored and the CLI falls back to direct Anthropic. If you see requests going to api.anthropic.com despite the var being set, pin Claude Code to a release where the integration is stable (check the issue for the current good version).

Same Bedrock-style strict validation risk. If Foundry's upstream is configured to relay to Bedrock, you can hit the same extra inputs are not permitted error documented in truefoundry.md. The same three suppressor env vars apply.

Troubleshooting

Symptom	Cause	Fix
Requests still hit api.anthropic.com	claude-code#11937 — Foundry env vars not picked up	Pin a Claude Code version that honors CLAUDE_CODE_USE_FOUNDRY=1; verify with --debug
404 on /anthropic path	Base URL missing the /anthropic suffix	Set ANTHROPIC_BASE_URL=https://<resource>.services.ai.azure.com/anthropic exactly
401 / 403	Wrong key or key from a different Foundry resource	Rotate via agents accounts set-key foundry
extra inputs are not permitted	Upstream Bedrock validator (Foundry-relayed)	Apply the DISABLE_PROMPT_CACHING=1 + CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 + CLAUDE_CODE_ATTRIBUTION_HEADER=0 triplet