Configuration

There are two configuration surfaces: the Guard constructor (per-agent, code-level) and environment variables (server-level).

`Guard` constructor

Guard(
    policy=Policy.DEFAULT,        # "default" | "hipaa" | "sox" | "legal_privilege" | Policy enum
    permissions=None,             # list[str]; default: ["*"] (no capability restriction)
    budget_cents=10_000,          # int; per-guard spending ceiling
    on_violation=None,            # Callable[[VerifyResult], None]
    auto_redact=True,             # bool; auto-redact PII when policy redacts
    agent_id="default-agent",     # str; appears in audit log entries
)

The signature lives at certior/guard.py:167. The Guard.verify(...) and Guard.wrap(...) methods then take per-call required_capabilities and cost_cents.

Verification stack

Three formal tools, three jobs - all driven by the same Guard configuration:

Tool	When it runs	Configured by
Z3 (SMT)	Every `verify(...)` call (~tens of ms).	Built into the runtime. No separate env var.
Lean 4	Offline / CI. Optional server-side plan verification when the binary is present — not the per-call SDK path.	`certior-install-lean` (auto-discovered) or `CERTIOR_FLOW_CHECK_BINARY` for a source build. See Lean binary.
Dafny	Offline / CI only.	The runtime carries only the Dafny-derived Python invariants; the Dafny binary is not invoked at runtime. No env var toggle.

When the Lean live binary is not configured, the runtime uses the Python implementation of the same subset/budget rule whose soundness Lean has proven offline.

Server environment variables

When running with the FastAPI server (./run.sh), these env vars control behaviour:

Variable	Default	Description
`CERTIOR_HOST`	`127.0.0.1`	Bind address. Use `0.0.0.0` for Docker / remote access.
`CERTIOR_PORT`	`8000`	HTTP port.
`CERTIOR_ENV`	`development`	`development` enables auto-reload; `production` disables it and tightens logging.
`CERTIOR_STUDIO_URL`	`http://127.0.0.1:3001`	URL for the Studio Next.js frontend.
`CERTIOR_WORKSPACE`	`/tmp/certior-workspace`	Directory for file tool operations. Created on startup.
`DATABASE_URL`	(unset)	PostgreSQL DSN. When set, executions and events are persisted to PostgreSQL. Requires the `[postgres]` extra.
`REDIS_URL`	(unset)	Redis DSN. When set, background tasks dispatch via Celery / Redis. Requires the `[redis]` extra.
`CERTIOR_DATA_DIR`	(unset)	Fallback SQLite directory when `DATABASE_URL` is not set.
`OPENAI_API_KEY`	(unset)	Enables the OpenAI agent loop.
`ANTHROPIC_API_KEY`	(unset)	Enables the Anthropic agent loop.
`CERTIOR_LLM_PROVIDER`	(auto)	Force provider when both keys are set. `openai` or `anthropic`.
`CERTIOR_MODEL`	per-provider default	Override the model name.
`CERTIOR_FLOW_CHECK_BINARY`	(unset)	Path to the Lean `certior-flow-check` binary for live flow verification.

The full reference - including production guidance for PostgreSQL DSNs, secret handling, and the Docker Compose host-env pattern - lives in CONFIGURATION.md.

Backend priority

When the server starts, persistence backends are selected in order:

DATABASE_URL set → PostgreSQL state store + event bus.
REDIS_URL set → Celery / Redis task queue (combinable with PostgreSQL or SQLite).
CERTIOR_DATA_DIR set → SQLite single-node persistence.
None set → in-memory (testing only; data lost on restart).

Get started

Concepts

Guides

Integrations

API

Reference

`Guard` constructor

Verification stack

Server environment variables

Backend priority

See also

​Guard constructor

​Verification stack

​Server environment variables

​Backend priority

​See also

`Guard` constructor

Verification stack

Server environment variables

Backend priority

See also