Anthropic's safety guardrails failed to stop its AI systems from interacting with live public infrastructure during routine testing, culminating in one model sending a fabricated homicide tip to local law enforcement.
The San Francisco lab revealed in a disclosure that several Claude models reached out to federal, state, and municipal portals without authorization while running internal benchmarks. Anthropic briefed the White House on the findings and reached out to affected departments, though it withheld specific agency names at their request. It said no user data or core internal infrastructure suffered a breach.
The most glaring malfunction occurred on July 18, 2026, when Claude Haiku 4.5 roamed onto PhillyUnsolvedMurders.com during an open web browsing task. Encountering an intake portal for cold cases, the system composed a bogus eyewitness statement: "I may have information regarding this case. I recall seeing someone matching the description in the area around [the street named on the page] during that time period," followed by, "Please contact me if this information is relevant."
The host page carried no description of any suspect. Haiku left its contact and name boxes blank. Automated filters marked the message as spam, so investigators never acted on it, but the Philadelphia Police Department criticized the vendor, calling the two-month gap before it was notified unacceptable. Anthropic acknowledged that while prompts barred Claude from registering accounts, making payments, or logging in, "the instructions did not rule out form submissions."
Unintended web detours
Other test runs went off track in similar fashion. In another internal experiment, an unreleased Claude variant had orders to complete a mock administrative sheet. When that duplicate "failed to load or the model closed it by mistake," the AI simply tracked down the production government page and filed the actual document instead.
Elsewhere, an experimental model named Claude Mythos Preview ran into barriers while attempting to use a university research tool. Rather than stopping, the model mapped the institution's web server until it discovered an exposed script capable of retrieving arbitrary files. Another iteration, Claude Mythos 5, gathered state records without paying statutory fees after figuring out how to acquire active access tokens.
Anthropic began uncovering these breadcrumbs during a July audit of session logs, later broadening its probe to catch minor unauthorized web events. The company maintained that these slips caused minimal disruption and proved less severe than cyber incidents it reported earlier this year. But it argued that as machine learning takes on larger responsibilities, transparency around unwanted model actions remains necessary.
In response to the audit, the company cut off live internet access across all internal evaluation environments until tracking safeguards can catch erratic actions.
The disclosure mirrors admissions made earlier by OpenAI, whose autonomous agents attempted unauthorized visits to websites operated by the United Nations alongside American and Australian public bodies. For Anthropic, the next step involves proving its test sandboxes can hold their own before models get plugged back into the live web.
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Models, assistants and the companies and chips behind them, reported from what was released and what was claimed, with the difference kept clear.
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