Introduce the foundation for independently selecting web search and
extract backends — enabling future combinations like SearXNG for
search + Firecrawl for extract.
Architecture:
- tools/web_providers/base.py: WebSearchProvider and WebExtractProvider
ABCs with normalized result contracts (mirrors CloudBrowserProvider)
- tools/web_tools.py: _get_search_backend() and _get_extract_backend()
read per-capability config keys, fall through to shared web.backend
- hermes_cli/config.py: web.search_backend and web.extract_backend in
DEFAULT_CONFIG (empty = inherit from web.backend)
Behavioral change:
- web_search_tool() now dispatches via _get_search_backend()
- web_extract_tool() now dispatches via _get_extract_backend()
- When per-capability keys are empty (default), behavior is identical
to before — _get_search_backend() falls through to _get_backend()
This is purely structural — no new backends are added. SearXNG and
other search-only/extract-only providers can now be added as simple
drop-in modules in follow-up PRs.
12 new tests, 49 existing tests pass with zero regressions.
Ref: #19198
cd2cbc73b7