ATC Security Pipeline Gets Fixes for Canonicalization Bug, CA Key Rotation, and Runtime Threats

A developer behind the Agent Trust Card (ATC) security pipeline has published a detailed follow-up addressing three vulnerabilities flagged by community reviewers. A canonicalization bug in JSON.stringify was confirmed to affect only top-level key sorting, leaving nested objects unsorted and potentially breaking signature verification; a recursive fix has been written and is being deployed. Plans for CA key rotation include versioning each ATC with a key ID, a re-signing workflow, and a revocation registry, with multi-signature support for high-value agents on the roadmap. Reviewers also raised a time-of-check vs time-of-use concern, where a skill could pass all eight static inspection layers at install time but later fetch a malicious payload from a remote server. To address this, the team is building continuous runtime monitoring that periodically re-runs installed skills in a sandbox and flags behavioral changes, alongside tool-catalog diffing and stricter egress allowlist enforcement.