Run-config reference

The run-config JSON controls how compiled IR is evaluated — discount rate, as-of date, parameter overrides, named scenarios, and Monte Carlo. Pass it with cfdl run --config run.json, cfdl_sdk.run(config=...), or the API server's config field.

Full shape

{
  "deterministic": {
    "annual_discount_rate": 0.10,
    "valuation_grain": "annual",
    "arithmetic": "decimal",
    "as_of": "2026-01-01",
    "parameters": {
      "inputs.base_rent": 1000.0,
      "cfg.exit_multiple": 8.0
    }
  },
  "scenarios": {
    "stress": {
      "annual_discount_rate": 0.12,
      "parameters": { "inputs.base_rent": 800.0 }
    }
  },
  "monte_carlo": {
    "trial_count": 1000,
    "seed": 12345,
    "distributions": {
      "inputs.exit_multiple": { "kind": "normal", "mean": 8.0, "stdev": 1.0, "clip": [5.0, 12.0] },
      "inputs.growth": { "kind": "uniform", "min": 0.01, "max": 0.05 }
    }
  }
}

Every section is optional; an empty config runs deterministically with the CLI's --rate fallback (default 0.0). The config structs reject unknown fields, so a misspelled key is a hard error, not a silent default. The authoritative shape is the run schema; this page restates it.

deterministic

• annual_discount_rate — the discount rate for NPV (annual; the engine publishes run.annual_discount_rate and run.periods_per_year back into the metrics).
• valuation_grain — "period" (default when omitted): each flow discounts at its own fractional year on the model grid. "annual": cash sums into calendar years and each year discounts once — the convention published sources use, and the setting to reach for when reconciling against one.
• arithmetic — "decimal" (default when omitted): what every published number uses. "excel_compat" reproduces a spreadsheet's float64 artifacts, for reconciling against a workbook rather than for producing an answer.
• as_of — valuation as-of date (YYYY-MM-DD).
• parameters — override map applied before evaluation.

Parameter keys

Four key shapes are recognized; anything else is ignored:

• inputs.<name> — an assumption. Prefer this one: a contract term declared as inputs.<name> is then drivable by scenarios and Monte Carlo alike without touching the model.
• stream.<name>:amount — replaces a stream's amount for every period, bypassing its expression.
• cfg.<path> — a config value read as cfg.<path> in expressions.
• obs.<path> — an observable read as obs.<path> in expressions.

scenarios

Named variants of the deterministic run. Each scenario may override the discount rate, as-of date, and parameters; results carry one entry per scenario alongside the base deterministic result, publishing the same metric map the deterministic block does.

monte_carlo

• trial_count and seed are required — there are no implicit seeds.
• distributions adds or overrides distributions at run time without touching the model, keyed by the same shapes as parameters and overriding an in-language assume x ~ Dist(...) of the same name. The kinds match the language's: fixed { value }, normal { mean, stdev }, uniform { min, max }, log_normal { mu, sigma }, triangular { min, mode, max }. Every kind accepts clip: [lo, hi], applied after the draw exactly as the language's clip=[...] is. stddev is a deprecated spelling of stdev; the language's spelling is stdev.

Each assumption draws from its own deterministic stream derived from the seed — results are byte-reproducible, and adding one assumption never changes another's draws.

Precedence

Run-config values override CLI fallbacks (--rate, --as-of). Scenario values override deterministic values for that scenario only.

Where results land

deterministic.metrics, one scenario summary per scenario, and monte_carlo.metrics with mean/stdev/min/max, percentiles p01–p99, and trials — the count of trials that published that name — for every metric, model-declared ones included. See the Results schema.