The code intelligence market is confusing. Sourcegraph calls itself code intelligence. CodeSee (now mostly shut down) called itself code understanding. Glue calls itself pre-code intelligence. They're all different products.
Sourcegraph: Code Search
Best at: Finding code across large, multi-repo environments. If you have 500 repositories and need to find every use of a deprecated API, Sourcegraph is unmatched.
Weak at: Understanding why code is structured a certain way. Sourcegraph searches code — it doesn't analyze it for features, dependencies, or knowledge patterns.
Use it when: Your primary problem is "I can't find where this code is."