# preCaution

- **Event:** [Built with Claude: Life Sciences](https://cerebralvalley.ai/e/built-with-claude-life-sciences)
- **When:** Jul 7 at 12:00 PM – Jul 14 at 12:00 AM (EDT)
- **Where:** Online
- **Team:** [Yuvraj Gupta](https://cerebralvalley.ai/u/theyuvrajgupta)
- **GitHub:** https://github.com/theyuvrajgupta/PreCaution
- **Demo video:** https://www.youtube.com/watch?v=D09dpqCn_s0
- **Gallery:** https://cerebralvalley.ai/e/built-with-claude-life-sciences/hackathon/gallery
- **Page:** https://cerebralvalley.ai/e/built-with-claude-life-sciences/hackathon/gallery/67

Early in a routine lab protocol, piranha acid is prepared, used, and its spent waste poured into
an acid waste carboy. A step later, someone rinses sodium azide buffer glassware into that same
carboy. The two are never combined in any single instruction. They meet in the vessel, because
the waste goes to a shared container, and the azide reacting with the carried-over acid releases
hydrazoic acid, which is toxic and potentially explosive. No ingredient-screening tool catches
this, because catching it means reading the procedure as a sequence of vessels and events, not a
list of chemicals.

That is what preCaution does. It reads a scientist's free-text protocol and produces a short,
sourced safety brief for that specific procedure, not a stack of data sheets to wade through. It
flags hazards that come from the procedure itself: reagents combined in one step, or waste
streams that quietly converge across steps through a shared vessel. It also flags where a step
leaves something its chemicals' own safety data calls for unstated, like ventilation or waste
handling, as a tentative prompt to confirm rather than a verdict.

Every hazard claim traces to a live lookup, PubChem for GHS hazard data and a NOAA CAMEO-sourced
table for reactive-group interactions, never a model's memory. The brief itself is composed by
code with zero model calls, so there is no generation step where an ungrounded claim could slip
in. The single claim that rests on Claude's reading of the protocol, that the azide enters that
specific carboy, is marked unverified on screen. It is the only claim marked that way, so the
marker carries weight.

What I found building it: the safety data that exists in structured, queryable form is
calibrated for industrial and hazmat chemistry and thins out fast for biological reagents.
preCaution is honest about that boundary in its own output rather than papering over it. The
person this is written for is usually a newcomer. In its first case study of an academic
laboratory, following the 2010 Texas Tech University explosion that seriously injured a graduate
student, the U.S. Chemical Safety Board found systemic failures in hazard evaluation and in
oversight by the principal investigators and the institution: a critical exposure limit existed
only as a verbal instruction, and none of the students the Board interviewed knew it. Those are
precisely the gaps a newcomer is least equipped to catch alone.

Existing lab-safety tools are systems of record for the institution. preCaution is a reasoning
tool for the person at the bench, about to run a protocol they did not write.

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Markdown version of https://cerebralvalley.ai/e/built-with-claude-life-sciences/hackathon/gallery/67. Site index for agents: https://cerebralvalley.ai/llms.txt · full text: https://cerebralvalley.ai/llms-full.txt