Environment variables¶

mcp-test prefers YAML for configuration but every value can be overridden via an environment variable thanks to ${VAR} and ${VAR:-default} interpolation in the loaded config.

Convention¶

The convention is MCPTEST_<UPPER_SNAKE> for project-specific values, plus a few un-prefixed standard names (LOG_LEVEL).

Common overrides¶

Variable	Used by	Example
`LOG_LEVEL`	Binary	`debug`, `info` (default), `warn`, `error`.
`MCPTEST_PORT`	`server.address`	`8080`
`MCPTEST_BASE_URL`	`server.base_url`	`https://mcp-test.example.com`
`MCPTEST_DATABASE_URL`	`database.url`	`postgres://mcp:mcp@localhost:5432/mcp_test?sslmode=disable`
`MCPTEST_DEV_KEY`	`api_keys.file[0].key`	`devkey-please-change`
`MCPTEST_OIDC_ISSUER`	`oidc.issuer`	`http://localhost:8081/realms/mcp-test`
`MCPTEST_OIDC_AUDIENCE`	`oidc.audience`	`mcp-test`
`MCPTEST_OIDC_CLIENT_ID`	`oidc.client_id`	`mcp-test-portal`
`MCPTEST_OIDC_CLIENT_SECRET`	`oidc.client_secret`	(confidential clients only)
`MCPTEST_COOKIE_SECRET`	`portal.cookie_secret`	32+ bytes, base64
`MCPTEST_INSECURE`	OIDC skip-signature gate	`1` to allow `oidc.skip_signature_verification`

Interpolation rules¶

${VAR} is replaced with the env value, or empty string if unset.
${VAR:-default} is replaced with the env value, or default if unset or empty.
Plain $VAR (no braces) is not interpolated. This is intentional so DSNs and other shell-shaped values round-trip.
The substitution happens on the raw YAML string before parsing, so it works for any field type.

Composing in compose¶

The bundled docker-compose.dev.yml shows the typical pattern: the binary container's environment: block sets the variables and the config file references them.

# docker-compose.dev.yml
mcp-test:
  environment:
    MCPTEST_DATABASE_URL: postgres://mcp:mcp@postgres:5432/mcp_test?sslmode=disable
    MCPTEST_BASE_URL: http://localhost:8080
    MCPTEST_OIDC_ISSUER: http://keycloak:8080/realms/mcp-test
    MCPTEST_OIDC_AUDIENCE: mcp-test
    MCPTEST_OIDC_CLIENT_ID: mcp-test-portal
    MCPTEST_COOKIE_SECRET: dev-cookie-secret-not-for-production-use-dev
    MCPTEST_DEV_KEY: devkey-please-change
  command: ["--config", "/app/configs/mcp-test.dev.yaml"]

Worth knowing¶

The binary doesn't read .env files. Use your shell, container runtime, or systemd unit to set variables.
Validation runs after interpolation, so a missing required variable surfaces as a config error rather than a YAML parse error.
Secrets in env vars show up in process listings on shared hosts. For production, prefer a config file mounted from a secret manager.