The original title is "Why I gave my AI agent read-only access to my spreadsheets"

Short summary

An opinion piece arguing that read-only access should be the default for AI agents connecting to spreadsheets, because write access creates risks from both misfired tool calls and prompt injection via cell content. The author advocates publishing single sheets as isolated MCP endpoints rather than granting broad OAuth access, and introduces PasteSheet, their tool that exposes only read tools so safety is structural rather than rule-based.

• •Read-only is the safer default for agent-to-spreadsheet access; write access enables silent data corruption and prompt injection
• •MCP tool-surface limitations provide structural safety that agent-agreed rules cannot
• •PasteSheet publishes sheets as read-only MCP endpoints with no write path to exploit

Generated with AI, which can make mistakes.