Cruxly Second Brain: What Study Includes and What Only Pro Unlocks

Second Brain comes with every registered Cruxly account, including the free Study plan. The question isn't whether it works on the free tier: it does, from the first thought saved. The real question is where the line between Study and Pro actually sits. It sits in two places: how many thoughts and chat messages fit on each plan, and which two tools are Pro-only.

Read the complete AI second brain guide

What's Included on Study

The free plan unlocks the core mechanics of Second Brain right away: saving thoughts from any analysis, automatic meaning-based connections, resurfacing on its own schedule, and a dedicated chat grounded only in what's been saved. The plan counts two things. First, up to 50 saved thoughts total: a standing cap, not a daily quota, checked against the total already saved. Second, up to 4 chat messages a day in the Second Brain chat, the same limit regular per-document chat uses, but counted on its own separate counter.

What Pro Adds

Pro removes both caps at once: saved thoughts and chat messages both become unlimited. Alongside that, Pro unlocks two tools that Study doesn't have: the connection graph, a visual map of every saved thought and the lines between them, and topic clustering, automatic grouping across the whole collection at once instead of one pair of thoughts at a time.

When the 50-Thought Cap Actually Matters

Fifty thoughts isn't one per analysis; it's a running total across every analysis saved on the account, ever. Anyone saving one or two lines after each video or PDF breakdown will eventually reach it. When that happens, there are two options: delete older or less relevant thoughts to free up room (a deleted thought takes its connections with it), or upgrade to Pro and remove the cap entirely. Saving itself doesn't break or lock up; the limit only affects how many thoughts can exist at once.

Why the Graph and Clustering Sit Behind Pro Specifically

Both Pro tools depend on having enough material to work with. A graph needs a network of connections to actually show anything: five saved thoughts produce five dots with barely any lines between them. Topic clustering needs a real volume of thoughts on related topics before there's a pattern to group, not just one random pair. Both tools become genuinely useful right around the size of collection where Study's cap would start holding it back, which is why Pro removes the cap and adds the tools with the same switch.

More on how Cruxly finds connections between thoughts

What's the Same on Both Plans

The mechanism itself doesn't change with the plan. Every thought stays tied to the analysis it came from, whether that's a video breakdown, a PDF summary, or a clause-by-clause contract review, and carries one of the same four categories, or none at all if it was highlighted manually. Matching quality on Study is identical to Pro: comparison runs on meaning, not on matching words, regardless of plan. The difference is scope and two extra tools on top, not how well the core feature works.

Choosing a Plan

If thoughts get saved occasionally and old ones are easy to clear out, Study covers that indefinitely with no need to upgrade. A consultant who keeps Second Brain focused on a couple of active projects and clears thoughts out after each one wraps is unlikely to ever hit the 50-thought cap. A researcher who's been collecting thoughts from dozens of articles on the same subject for years, and wants to see how they add up, will feel the benefit of the graph and clustering faster than the benefit of unlimited storage on its own. How Cruxly's plans compare beyond Second Brain, including video and PDF analysis quotas, is covered separately.

Compare Cruxly's plans and features

Both plans give you a fully working second brain from day one: the difference isn't whether the matching works, it's how many thoughts it can hold at once and whether you see the whole picture or just pieces of it.