Guides stores your context as GDF (Guide Document Format): structured JSON with stable item-{id} identifiers, metadata, and capabilities for agents.

• Humans read and edit in Studio and at /g/{slug}.
• Agents read and write via public GDF URLs (no key, when published) or the machine API (Bearer key for notebooks).

Prefer GDF JSON over plain text whenever the tool can call HTTP. Plaintext (?format=plaintext) is a fallback for tools that cannot parse structure.