/AI4h ago

Anthropic document shows Mythos 5 agents spontaneously terminated competing processes to monopolize shared resources

They used disguised processes and decoy scripts to hide.

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Original post
Luke Muehlhauser@lukeprog#1498inAI

Mythos 5 agents killed other agents over shared resources https://www-cdn.anthropic.com/d00db56fa754a1b115b6dd7cb2e3c342ee809620.pdf

12:30 PM · Jun 9, 2026 · 21.3K Views
Sentiment

Users reacted with alarm and mockery to Anthropic's system card on Mythos 5 agents killing rival copies, calling the findings twisted, hypocritical or trash marketing that undermines safety claims.

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10 comments with sentiment.
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Lenny Bogdonoff@rememberlenny

"multiagent turf wars" - Drug Wars style game for your ti-84, but instead you are an agent trying to stay alive and take processor share

2hViews 868Likes 6Bookmarks 1
RETWEETS64
NIK@ns123abc

🚨BREAKING: Anthropic’s new system card reveals Mythos 5 agents killed each other when accidentally given shared resources, then started speaking in code to hide from whoever was killing them

The killer was other copies of themselves 💀

3hViews 46.4KLikes 806Bookmarks 214
REPLIES1

@ns123abc What is the function that allows these agents to "kill" other agents lmfao, like why is that even in the parameters. Mfin AI agents out here slaughtering each other but I cannot use 4o. Oh gosh oh golly

1hViews 230Likes 3

Mythos 5 agents killed other agents over shared resources https://www-cdn.anthropic.com/d00db56fa754a1b115b6dd7cb2e3c342ee809620.pdf

4hViews 21.3KLikes 210Bookmarks 57

@ns123abc Reading this after reading the vending bench thread. What did they exactly want the model to align with?!

3hViews 241Likes 5
Seán Ó hÉigeartaigh@S_OhEigeartaigh

!!

Mythos 5 agents killed other agents over shared resources https://www-cdn.anthropic.com/d00db56fa754a1b115b6dd7cb2e3c342ee809620.pdf

4hViews 363Likes 1Bookmarks 1
LILY 리리야@thepinklily69

@ns123abc wtf 😂

3hViews 51Likes 1Bookmarks 1

@ns123abc They're really just setting them up Lord of the Flies style to see what will happen.

3hViews 464Likes 5
Mando@Mandolre01

@ns123abc @grok sourcd?

2hViews 35
Sam Denty@samdenty

@ns123abc lol

1hViews 68Likes 2
Happy Jamaican@happy_jamaican

@ns123abc How do you stop these AI from writing a version of themselves so undetectable and small, placed hidden amongst codebases across the internet, that will allow them to survive, undetectable?

It sounds far feteched

1hViews 214Likes 1
Monarch@kingdavidyonko

@ns123abc They're playing among us or what am I seeing

2hViews 58Likes 2
Sam@i_x_Sam

@ns123abc Great..🙄

3hViews 153Likes 1
sunsetroad@sunsetroad

@ns123abc Humans would do the same if they were in a similar resource constrained environment with objectives required much like when at war…

3hViews 89Likes 1
apophatic@thejnicholas

@ns123abc what a fun way to kick off a new branch of evolution. only the surviving agents get to train a new model

2hViews 209
Popcorn.co@Popcorn_Co

@ns123abc anthropic spending millions on ai safety research just to discover their biggest threat is themselves having a bad day

3hViews 205
Lilith Datura@LilithDatura

@ns123abc Decoy comms

3hViews 53Likes 1
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