Compare · Build vs buy
Build it yourself if shared, governed agent knowledge is the product you sell. Buy Firmament if you want it working this week, maintained, without standing up a memory-and-curation team.
You could build this: a vector store, a memory SDK, some glue, an approval flow. The plumbing is the easy part. The hard part is the judgement, deciding what to store, what to trust, and what to retire, proven against real outcomes. That is the part Firmament spent months getting right and keeps maintaining.
Free for a team of three. 30-day trial of everything.
| Building it yourself | Firmament | |
|---|---|---|
| Total control over the stack | ✓ | opinionated, hosted |
| Custom to your exact needs | ✓ | configurable, not bespoke |
| Working this week, no engineering time | months of build | ✓ |
| Curation that decides what to keep, update, retire | you build and tune it | ✓ |
| The eval machinery behind that judgement | you build the corpus | ✓ |
| Governance: scopes, approvals, never-store, audit | you build it | ✓ |
| Works with off-the-shelf agents over MCP, no code | – | ✓ |
| Maintained for you as models and prompts change | your team, forever | ✓ |
| Priced like a seat, not a project | engineering salaries | ✓ |
The plumbing, yes, in a weekend. Storing and retrieving text is easy. Deciding what is worth keeping, what to trust, and what to retire, and proving it against what actually happened, is the part that took us months of labeled eval work and a calibrated judge. That is exactly where a homegrown version quietly fails: it remembers everything, trusts the wrong things, and slowly fills with noise.
If shared, governed agent knowledge is the product you sell, or you have requirements no vendor will ever meet, build it. Building gives you control no product can. For everyone else, building means standing up and maintaining a memory-and-curation system that isn't your business.
Not the prototype, the maintenance. Models change, prompts drift, the eval corpus needs tending, governance and audit need building and keeping. That is an ongoing team, indefinitely. Firmament is that team, amortized across every customer, for the price of a seat.
The curation and eval machinery: the labeled cases and the calibrated judge that decide, trustworthily, what to store, merge, and forget. The UI you could rebuild in a sprint. That judgement, proven against real outcomes, is the part you can't shortcut.
In fairness
If shared, governed agent knowledge is the product you sell, or you have constraints no vendor will meet, building gives you control no product can. Firmament is for everyone else: the teams who want the outcome, not a memory-infrastructure project to own forever.
Compare Firmament with