> ## Documentation Index > Fetch the complete documentation index at: https://docs.ancha.io/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > These docs describe the Ancha CLI, npm package @ancha-labs/cli, and the hosted workspace at app.ancha.io. Coding agents should start at https://docs.ancha.io/coding-agents. Run the CLI as `ancha` after `npm install -g @ancha-labs/cli`, or as `npx -y @ancha-labs/cli` without installing. Pass --json for machine-readable output, or set ANCHA_JSON=1. Every command ends with a `next:` line naming the next command. Exit codes: 0 pass, 1 a check failed or a comparison regressed, 2 usage, config or authentication error, 3 infrastructure error, 4 unimplemented endpoint with --strict. # ancha replay > Run one recorded attempt again with its saved world and seed, recorded answers from people, and your current agent. Compare its actions and check outcomes. `ancha replay` runs your current agent against one attempt's saved world and seed. People answer from their recording while the conversation matches. The result shows the first different agent action and the checks whose outcomes changed. ```bash theme={null} ancha replay [options] ``` | Argument | Description | | - | - | | `attempt` | `/` or `latest/`, for example `latest/trial-support-reply-1`. | | Option | Description | | - | - | | `--agent ` | Command to run the agent. Defaults to the agent in your current `ancha.yaml`. | | `--people ` | `live` or `strict`. Controls what happens when people cannot answer from the recording. See below. | | `--out ` | Directory containing the recorded run. The replay is saved here as a new run. Default `.ancha/runs`. | | `--pass-env ` | Give the agent this shell variable. Repeat for each variable. | | `--inherit-env` | Give the agent the whole shell environment, including any real credentials it contains. | Global options such as `--json`, `--config` and `--local` also apply. See [CLI overview](https://docs.ancha.io/cli/overview.md#global-options). ## Choose an attempt Use a finished local `ancha run` attempt. Its directory is listed in `scenes[].trialsDetail[].dir` in `ancha report --json`. ```bash theme={null} ancha report latest --json ancha replay latest/trial-support-reply-1 --people strict --json ``` Replace `trial-support-reply-1` with the directory from your run. To keep comparing against the same original attempt, use its run ID instead of `latest`: a replay writes a new run and updates `latest`. The original run must still have `inputs.json` with the saved case, and the attempt must have `trace.jsonl` and `checks.json`. Replay also reads `people.jsonl` when it exists. An older run without the saved case cannot be replayed. Replay uses the recorded scene and checks. It reads the agent settings from your current config, so you can edit the agent and replay the same attempt: ```bash theme={null} ancha replay run_example/trial-support-reply-1 --agent "node agent.mjs" --people strict ``` Replace `run_example/trial-support-reply-1` with your original attempt. Use [`ancha explain`](https://docs.ancha.io/cli/explain) or [`ancha report`](https://docs.ancha.io/cli/report) with the new run ID to inspect the replay. ## People after a change | Mode | Behavior | | - | - | | `live` | Reuse recorded answers while the conversation matches. After a mismatch, people answer through a model. This needs `OPENROUTER_API_KEY`, a signed-in workspace, or a world server that can answer. | | `strict` | Reuse recorded answers. If a person needs an answer the recording cannot supply, stop replaying their conversation and mark the replay invalid. | With people in the world, the default is `live` when a model is available and `strict` otherwise. A world without people defaults to `live` and needs no people model. A different agent write appears in `diverged`. It does not by itself make a strict replay invalid. When a person's conversation no longer matches the recording, `people.divergence` explains why. A strict replay then has `comparable: false`, `valid: false` and `invalidReason: "diverged"`, and exits `3`. Do not use those check outcomes to judge the agent. ## Output With `--json`, replay prints NDJSON: `run_started`, `trial_started`, `trial_finished`, then `replay_finished`. The last event contains the comparison, rather than a `run_finished` event. | Field | Meaning | | - | - | | `replayOf` | Original attempt as `/`. | | `runId` | New run containing the replay. | | `peopleMode` | `live` or `strict`. | | `diverged` | `null` if the agent's writes match. Otherwise `{ atAction, recorded, now }`: the first difference, numbered from 1. A missing action is `null`. | | `people` | `replayed` and `live` answer counts, and `divergence`: the first conversation mismatch, or `null`. | | `comparable` | `false` when strict mode could not continue a person's conversation. | | `valid` | Whether the replay can be judged as an agent result. | | `invalidReason` | Present when invalid: `diverged` for strict conversation replay, or `harness` for an execution problem. | | `checks` | Each check's `id`, `required` and `passed`, plus `was` when its recorded outcome is available. | | `changed` | IDs of checks whose outcomes differ from the recording. | | `next` | The `ancha explain` command for the new run. | The action comparison excludes `GET` and `HEAD`. It also excludes Slack methods ending in `list`, `history`, `replies`, `info`, `test`, `members`, `lookupByEmail` or `open`. See [JSON events](https://docs.ancha.io/coding-agents.md#json-output). `ancha schema replay_finished` prints the complete schema. ## Exit codes | Code | Meaning | | - | - | | `0` | The replay is valid and its required checks pass. | | `1` | The replay is valid but its verdict is `fail`. | | `2` | Invalid arguments, an unavailable attempt, a config error, or live people without a model. | | `3` | The replay is invalid: a strict conversation diverged or execution failed. | ## Related topics - [ancha schema](https://docs.ancha.io/cli/schema.md) - [For coding agents](https://docs.ancha.io/coding-agents.md) - [CLI overview](https://docs.ancha.io/cli/overview.md) - [ancha.yaml](https://docs.ancha.io/reference/ancha-yaml.md) - [ancha run](https://docs.ancha.io/cli/run.md) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.