Module opcodes 

Pipe opcodes (docs/ARCHITECTURE.md opcode table). Event pushes reuse 1..=6 as the event kind with flags = event — dispatch must branch on the flag before the opcode.

Constants

FLUSH_RESERVED

Number reserved, deliberately unimplemented (client-driven flush is a local-DoS lever — ADR-0016).

HELLO

Hello: connection handshake and version negotiation (maps to fmf_abi_version).

INDEX_START

IndexStart: start indexing the given volume (maps to fmf_index_start; persisted to service.json).

INDEX_STATUS

IndexStatus: return index progress and state (maps to fmf_index_status; same shape as ListVolumes).

LIST_VOLUMES

ListVolumes: return the state and entry count of every volume (maps to fmf_list_volumes).

QUERY

Query: run a query and return result_id and the entry count (maps to fmf_query).

RESULT_FREE

ResultFree: free result_id’s result handle (maps to fmf_result_free).

RESULT_PAGE

ResultPage: fetch a row page from result_id’s results (maps to fmf_result_page).

SERVICE_INFO

ServiceInfo: return service-specific runtime info (uptime_ms / connections / version).

STATS

Stats: return the engine’s metrics snapshot (maps to fmf_engine_stats).

SUBSCRIBE

Subscribe: push events to this connection from now on (maps to fmf_set_event_callback(cb≠NULL)).

UNSUBSCRIBE

Unsubscribe: stop pushing events (maps to fmf_set_event_callback(NULL)).