- core.md: human-readable specification covering message format, session manifest, tool taxonomy (sensors/actuators/generators), tool invocation, events, capabilities, time/causality, memory, errors, extension rules, security, conformance. - schemas/aicc.schema.json: JSON Schema for all message types, validated with Draft 2020-12. - LICENSE: MIT. - README.md: repository layout, design principles, versioning, conformance criteria.