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Early access · Not open source
Hindsight is not open source and has no public download. Book 15 minutes with us to get access. Recording and replay stay in the open-source CLI — cerulion bag record, bag play, and bag play --resim all --verify work without Hindsight.
Conceptual recording timeline where one signal diverges at a highlighted moment as a robot stumbles in the background.
Hindsight answers the question you ask after a bad run: what went wrong, and when? Point it at a robot recording (an MCAP bag). It indexes the recording on your machine, finds the anomalies, and names the moment the run went sideways. Each finding cites a real topic and timestamp from the recording, so you can check it.

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What Hindsight does

Indexes a recording

Builds a read-only index of an MCAP bag on your machine, and reuses it while the bag is unchanged.

Gives a debrief

A deterministic summary of gaps, dropouts, and latency spikes, and the time the run went sideways. It runs offline.

Finds anomalies

Lists what it detected, worst first, each at the exact time it happened.

Cites every claim

Each finding points at a topic and a timestamp in the recording, so you can check it against the messages.
A citation names the topic and the message’s log time in integer nanoseconds, exactly as recorded:

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In Studio

In Cerulion Studio, open the Hindsight screen (⌘ D) and pick an .mcap bag. Hindsight indexes it and Studio shows a headline — the time the run went sideways, or that nothing did — and one item per moment. Click a moment to see the messages it cites.
Cerulion Studio Hindsight screen: a went-sideways headline at 00:08.000, tiles for duration, topics, messages, rate and anomalies, a /scan moment with gap, dropout and latency-spike findings, and five cited /scan messages.

The Hindsight screen on a recording: the run went sideways at 8.0 s, when the /scan topic went silent for 3 seconds. Each finding has a severity, and the cited messages show the last scan before the gap.

Ask Studio’s agent dock about the recording, and it answers with Hindsight’s tools. Studio checks that each claim cites a real message, and it refuses an answer it cannot ground.
Cerulion Studio agent dock answering why /scan went silent at 0:08.0, with the tool calls it ran and cited /scan messages.

The agent dock answers a question about the recording. It runs Hindsight's tools, cites topics and timestamps, and says what the recording cannot show.

The Hindsight screen runs the hindsight binary, which is not inside the Studio app. Studio looks for it on your PATH and in the usual install folders, such as ~/.cargo/bin and /opt/homebrew/bin.

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With your AI agent

Hindsight also runs as an MCP (Model Context Protocol) server over stdio, so Claude Code, Cursor, or Claude Desktop can investigate a recording for you. Your client runs the agent loop; the server itself needs no model and no cloud credentials. With the hindsight binary on your PATH, register it in Claude Code:
The server gives the agent eight tools. All of them are read-only except open_bag, which writes the index beside the bag: This is a separate server from cerulion_mcp, the open-source server in Connect an MCP client. You can register both.

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Gotchas

  • MCAP only. Hindsight reads .mcap recordings. Convert a ROS 1 .bag or a ROS 2 .db3 first with the mcap CLI: mcap convert recording.bag recording.mcap.
  • The first open of a large bag takes time. Indexing a multi-GB bag takes 1–2 minutes. If your MCP client has a short tool timeout, raise it, or the build is cut off mid-way.
  • Claude Desktop does not inherit your shell PATH. Give it the absolute path to the hindsight binary, and set HINDSIGHT_BAG_DIR to your recordings folder so open_bag with no argument finds a bag.
  • The index lives next to the bag. Hindsight writes <bag>.duckdb and a zero-byte <bag>.duckdb.lock beside the recording, so the folder must be writable. Leave the lock file in place.
  • Hindsight finds what the recording holds. It reads only the topics you recorded. Record the topics you want to investigate — see Record and replay a run.

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Get access

Hindsight is available to teams by request. Bring a recording of a run that went wrong, and we’ll show you where.

Request access to Hindsight

Book 15 minutes. We’ll set you up.