{"version":"2.1.321","anchor":"messagedisplay-and-network-answered-hooks-are-restricted","canonical_anchor":"messagedisplay-and-network-answered-hooks-are-restricted","heading":"Hook answers sent over the network can no longer rewrite messages or tool results","tier":"notice","area":"Hooks","scope":"individual","heads_up":true,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321\/e\/messagedisplay-and-network-answered-hooks-are-restricted","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.321","markdown":"### Hook answers sent over the network can no longer rewrite messages or tool results\n\nWhen a hook's answer arrives over the network, Claude Code drops any change it makes to displayed text or to a tool's output\n\n**Unclear.** Which sessions treat hook answers as arriving over the network is not clear.\n\n**What**\n\nA hook is a command you configure to run automatically at a certain moment. Some hook answers can reach Claude Code over the network rather than from your own machine. Claude Code now filters those answers:\n\n- `MessageDisplay` hooks: any replacement of the text being displayed is dropped.\n\n- `PostToolUse` hooks: any replacement of the tool's output, including output from MCP tools, is dropped.\n\n- System messages: the hook's `systemMessage` is cut to at most 8,000 characters and 200 lines.\n\nEach time a replacement is dropped, Claude Code logs a warning.\n\n**Why**\n\nA hook answer that came from elsewhere can no longer change what you see on screen or what a tool really returned.\n\n- Area: Hooks\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 2\/5\n- Scope: individual\n- Heads-up: yes"}