M5a task 04 stopped twice on the chat-template tags the check refuses.
The first time, the model read them in a file and took them for its own
template. The second time, it spelled them out in its own reasoning.
Measured on straylight: the think and tool-call tags are one token
whatever the tokenizer's flag. Inside any chat message, the turn
markers become control tokens, so a tool result can forge a system
turn.
Adds the rule to AGENTS.md, and proposes neutralizing the tags in
loopd as an open decision.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
