MCP list caching and tool poisoning

The 2026-07-28 Model Context Protocol specification is out. One interesting addition for application security: List results are cacheable Responses from tools/list , prompts/list , resources/list , and resources/read now carry ttlMs and cacheScope ( SEP-2549 ). This allows clients to determine the best caching strategy for responses and reduce unnecessary re-fetching. On paper, cache hints help…