Codex

Configure Codex to use Prism through the Responses API.

Copy for your agent

Follow https://docs.prisminference.com/guides/codex to configure Prism in my
user-level Codex settings. Preserve unrelated settings and never repeat my API
key to me or include it in your response.

If no key exists, ask the workspace owner for an existing PRISM_API_KEY.

Configure

Set PRISM_API_KEY in the environment that launches Codex. Merge this into ~/.codex/config.toml:

model = "deepseek-v4.1-flash"
model_provider = "prism"
web_search = "disabled"

[model_providers.prism]
name = "Prism"
base_url = "https://api.prisminference.com/v1"
env_key = "PRISM_API_KEY"
wire_api = "responses"

Keep the provider at user scope; Codex ignores custom providers in project configuration. Do not put the key in config.toml.

Verify

codex doctor --json

Codex sends the bare model ID deepseek-v4.1-flash to Prism’s stateless POST /v1/responses endpoint. Web search remains disabled because Prism does not provide OpenAI-hosted tools.