# Current dynamic tool-group loading

`pi-tool-search` keeps full low-frequency schemas hidden behind a compact, validated group catalog.

1. `session_start` activates `tool_search`, the six Pi core tools, and configured `alwaysEnabled` names. These pinned tools do not consume the dynamic-group budget.
2. Hidden definitions are hashed with grouping constraints and matched against `extensions/bundle-groups.ts`. Available standard tools receive checked-in groups; unavailable optional tools are omitted.
3. If every hidden tool is recognized, the bundle catalog is used directly. No model call or per-user cache is required.
4. Additional tools receive immediate deterministic prefix/source groups. A matching model-enriched cache is reused only if it preserves all checked-in bundle assignments.
5. Only a hybrid catalog with unrecognized tools can call `ModelRegistry.complete()`. The prompt marks bundle assignments as fixed; validation rejects any response that moves them.
6. Code validation still requires every exact tool name exactly once and rejects unknown names, duplicates, oversized generated groups, omissions, and tool-card/group mismatches. Generated text never changes executable schemas.
7. Loading a group calls `setActiveTools()` with its original full tool definitions. Pi supplies newly added schemas on the next model request.
8. Group load and member execution update an in-session LRU counter. Loading past `maxActiveGroups` or `maxDynamicTools` removes the least-recently-used dynamic groups.
9. `turn_start` notices tool or grouping-configuration changes by hash, resets stale dynamic groups, and reconstructs the checked-in/hybrid catalog.

The standard bundle assigns the official Hippo Pi extension's five `hippo_*` tools to recall and management groups. `context_tree_query` remains in `memory-recall` because it recovers condensed tool output; retired Hermes names and third-party `tff-memory_*` names are not seeded.

A purely additive first load receives Pi's native dynamic-tool result propagation. A replacement that evicts one group while adding another is intentionally non-additive; current Pi detects the removal and uses its safe next-request fallback instead of attaching an invalid additive-only hint.

A model cannot call a schema it had not received in an already-generated assistant response. `tool_search` therefore returns normally, and the next model request sees the activated group's complete schemas. No provider payload rewriting, proxy dispatch, hidden steer message, old package alias, or duplicate Pi runtime is used.
