Claude Code users debate MCP instruction reliability

The real signal here is not “tools are ignored,” but that instruction hierarchy and formatting still dominate agent reliability in long contexts.

• –The thread is early-stage anecdotal evidence, not a controlled benchmark, but it matches a common developer pain point in agent workflows.
• –Anthropic tool-use docs explicitly route `tool_result` content back into model reasoning, so outright “tool output is low-authority by design” is too strong.
• –Claude Code docs note that `@file` references can automatically pull adjacent instruction files (like `CLAUDE.md`), which can make file-based guidance feel stickier in practice.
• –For teams building agents, this points to better instruction architecture: clear priority rules, compact tool outputs, and repeated critical constraints near execution steps.