Based on the provided context and our previous conversation, Sagacity does cache the index of the codebase to improve performance and avoid re-indexing on every run.

The relevant file contents show that the `load_index_cache` function tries to load a cached index from the `index_cache.json` file. If the cache file exists, and the cache is not older than 1 hour (3600 seconds) and there are no changes detected in the codebase, then the cached index is used. Otherwise, the `index_codebase` function is called to re-index the codebase.

The caching mechanism is implemented in the `initialize_codebase_index` function, which first tries to load the cache and checks if it's valid. If the cache is valid, it uses the cached index. If not, it calls `index_codebase` to create a new index and then saves the new index to the `index_cache.json` file using the `save_index_cache` function.

So, to summarize, yes, Sagacity does cache the index of the codebase to avoid unnecessary re-indexing, but it also has a mechanism to detect changes in the codebase and re-index when necessary.