subscription

Strip the dynamic suffix after : from a namespace segment.

Whether event_namespace starts with prefix.

Segments compare literally first; if the prefix segment contains no :, the candidate is also compared after its dynamic suffix is stripped. Mirrors is_prefix_match in api/langgraph_api/protocol/namespace.py.

Whether event_namespace matches any of prefixes within depth.

Map a protocol event's method to its subscription channel.

Returns None for unrecognized methods so new server-side channels (e.g. from extension transformers) don't break existing clients.

Whether event should be delivered for definition.

Aggregate a set of subscription filters into one covering filter.

Direct port of client/stream/index.ts:#computeUnionFilter.

• Channels are unioned.
• Namespaces: if any subscription omits namespaces (wildcard), the union is unscoped (omits the key). Otherwise, deduplicated union.
• Depth: if any subscription omits depth (unbounded), the union is unbounded (omits the key). Otherwise, take the max. depth=0 is a valid bounded value — never omit when all subscriptions provide it.

Whether coverer is a superset of target.

Direct port of client/stream/index.ts:filterCovers. Depth coverage accounts for namespace-prefix offset: a scoped coverer needs enough depth to absorb the extra levels of any deeper target namespace prefix.