# `flow/run/dry-run` Source: [`src/flow/run/dry-run.ts`](https://github.com/AI-for-dev/combo/blob/main/src/flow/run/dry-run.ts) `dryRunFlow`: `runFlow` itself, with every agent turn, every check, every commit and every question answered by a script. The same walk, the same `spawn`, the same events. Only the session under each subagent and the `check` port are scripted, so a typed answer goes through the real `submit` tool, a verdict through the real `verdict` tool and its ledger, and a failure takes its real path, retries and `fail-fast` included. Nothing of the world is touched: it takes a `CheckedFlow`, no working directory is given, no script is read, no model is reached and git is never run. `diff` reads as an empty text, since no agent wrote anything, and a `copies: true` block makes no copy: each of its branches reads as landed, and its copy is a journal fact alone. Given `from`, it resumes that journal through the same `resumePoint` a real resume takes. ## `DryRun` *type* ```typescript export type DryRun = | (FlowResult & { readonly journal: readonly JournalEntry[] }) | { readonly ok: false; readonly unscripted: string; readonly journal: readonly JournalEntry[]; readonly usage: Usage } | { readonly ok: false; readonly faults: readonly AnswerFault[] } | { readonly ok: false; readonly refused: string }; ``` How a dry run ended: as the flow did, or at the first visit its script did not answer, which is no outcome of the flow's; or refused before the start, with every fault of the script, or a journal `from` a resume would refuse, with why. The journal holds every fact a run would write, in order, the run's end last. Its tokens and cost are zero, since a script spends nothing; the time is measured, like any run's. ## `dryRunFlow` *function* ```typescript export async function dryRunFlow(checked: CheckedFlow, input: unknown, answers: Answers, options: DryRunOptions = {}): Promise { /* … */ } ``` Runs `checked` on `input`, each agent turn, check, commit and question answered from `answers`. ## `DryRunOptions` *type* ```typescript export type DryRunOptions = Pick & { /** A journal to resume, as `resumeFlow` resumes a run directory's: its facts come first in the one handed back. */ readonly from?: readonly JournalEntry[]; }; ``` What a dry run varies: what a run does, short of reaching the world.