{"version":"2.1.317","anchor":"prototype-pollution-key-and-permission-rule-tweaks","canonical_anchor":"prototype-pollution-key-and-permission-rule-tweaks","heading":"A __proto__ key is now skipped when Claude Code measures a structure's size","tier":"internal","area":"Internals","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.317\/e\/prototype-pollution-key-and-permission-rule-tweaks","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.317","markdown":"### A `__proto__` key is now skipped when Claude Code measures a structure's size\n\nWhen measuring how large a piece of data is, Claude Code now skips a key named __proto__ and counts it as left out\n\n**What**\n\nWhen Claude Code measures how large a piece of data is, it now skips a key named `__proto__` and counts it as left out. `__proto__` is a special name in JavaScript that can cause unexpected behaviour if it is treated like an ordinary key. Separately, permission rules are now read together with whether they allow or deny.\n\n**Why**\n\nThis is a small hardening change and is not expected to change what you see.\n\n- Area: Internals\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 0\/5\n- Scope: individual\n- Heads-up: no"}