Anthropic’s tool calling was exposed as XML tags at the beginning, before they introduced the JSON API. I expect they’re still templating those tool calls into XML before passing to the model’s context

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pocketarc 6 hours ago | parent | next [-]

Yeah like I remember prior to reasoning models, their guidance was to use <think> tags to give models space for reasoning prior to an answer (incidentally, also the reason I didn't quite understand the fuss with reasoning models at first). It's always been XML with Anthropic.

	▲	wolttam 6 hours ago \| parent [-]
		Exactly the same story here. I still use a tool that just asks them to use <think> instead of enabling native reasoning support, which has worked well back to Sonnet 3.0 (their first model with 'native' reasoning support was Sonnet 3.7)

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scotty79 2 hours ago | parent | prev [-]

Can you sniff it out with Wireshark?

	▲	wolttam 40 minutes ago \| parent [-]
		They don't expose the raw context over the wire, it's all pre/post processed at their API endpoints.