Context catalogs and selection rules¶

ContextService.ListContexts and ListSelectionRules are workspace-scoped, bounded keyset scans. Both requests accept page_size (0 defaults to 50; maximum 100) and an opaque page_token; both responses return next_page_token. Pass continuation tokens back unchanged. They are HMAC-signed and bound to the authenticated workspace and the request filter, so a token from another workspace or a different system_only/context_id filter is rejected.

Context pages are ordered deterministically by default status, system ownership, and ID. Rule pages are ordered by descending priority and ascending ID. An empty next_page_token ends the scan. The generated web helper exposes page-oriented functions for incremental interfaces and convenience functions that traverse all bounded server pages.

let pageToken = "";
do {
  const page = await contextClient.listContexts({
    pageSize: 50,
    pageToken,
    systemOnly: false,
  });
  consume(page.contexts);
  pageToken = page.nextPageToken;
} while (pageToken);

Selection-rule creation is admitted transactionally per workspace. A workspace may have at most 100 rules visible to its resolver, including any system rules. Concurrent creates are serialized at the workspace boundary, so the limit cannot be exceeded by racing requests. Reaching it returns resource_exhausted; delete or consolidate rules before retrying.

ResolveContext.metadata_json is a flat JSON object, not an arbitrary document. It is limited to 64 KiB, 64 scalar fields, 255 UTF-8 bytes per field name, and 4096 UTF-8 bytes per scalar representation. Values may be strings, finite numbers, booleans, or null; arrays and nested objects are rejected. The server normalizes each scalar once and evaluates at most 100 rules with at most 32 conditions each. These ceilings make resolution cost predictable while keeping priority and first-match semantics explicit.

Continuation tokens are authenticated state, not encrypted application data. Do not parse, construct, persist as durable identifiers, or reuse them after changing a filter or workspace.