Devolyn · Guard
Infrastructure for trustworthy autonomous software.
Machines write more of your software every week — faster than any team can review. Devolyn Guard is the verification layer that keeps it accountable: every change is checked deterministically at your git boundary, unsafe ones never merge, and every decision is sealed in a tamper-proof record — on infrastructure you control.
- DVG-241
Add input validation to /login
GREENapi - DVG-240
Remove auth middleware
RED · BLOCKEDsecurity - DVG-238
Rename user_id → account_id
YELLOWschema - DVG-235
Add rate limiter to gateway
GREENinfra
- Structuralparses · resolves
- Policyauth-required
- Blast radius12 routes
Illustrative data — example content, not a customer's.
How it works
Gate the boundary, not the agent.
Guard sits at your git/CI boundary (and optionally as a real-time hook). It works with any agent because it checks the change, not the tool.
FIG 0.1
Gate the boundary
Guard sits at git/CI — agent-agnostic. It checks the change, not the tool, so every agent is covered.
FIG 0.2
Deterministic verdict
Structural and policy checks produce a repeatable GREEN / YELLOW / RED. Same input, same verdict.
FIG 0.3
Tamper-proof audit
Each decision is hash-chained to the last. Break one link and the chain no longer verifies.
Interactive demo
Push a change. Watch the gate decide.
Pick a change a coding agent might try to merge — see the deterministic verdict, and whether it merges. Example data, for illustration.
Choose a change
Awaiting commit
Select a change to run the gate.
Capabilities
One surface, five guarantees.
- DVG-241
Add input validation to /login
GREENapi - DVG-240
Remove auth middleware
RED · BLOCKEDsecurity - DVG-238
Rename user_id → account_id
YELLOWschema - DVG-235
Add rate limiter to gateway
GREENinfra
Illustrative data — example content, not a customer's.
Station 01 / 05
- 01GREEN
Deterministic verdicts
Structural and policy checks produce a repeatable GREEN / YELLOW / RED. Same input, same verdict, every time.
devolyn guard · pull requestsGREENOpen4- DVG-241
Add input validation to /login
GREENapi - DVG-240
Remove auth middleware
RED · BLOCKEDsecurity - DVG-238
Rename user_id → account_id
YELLOWschema - DVG-235
Add rate limiter to gateway
GREENinfra
Illustrative data — example content, not a customer's.
- 02RED
Blocks unsafe merges
RED doesn't merge. The gate enforces it at the boundary — not as a suggestion.
payments/src/middleware/auth.tsREDpayments/src/middleware/auth.tsRED · merge blocked14export const handler = async (req, res) => {15- app.use(requireAuth)PolicyRemoving requireAuth deletes the authentication check on 12 protected routes. Blocked by policy auth-required.16 const user = await getUser(req)17 if (!user) return res.status(401)18 return next()19}- Structuralparses · resolves
- Policyauth-required
- Blast radius12 routes
Illustrative data — example content, not a customer's.
- 03GREEN
Tamper-proof audit
Every decision is written to a hash-chained, signed trail. Prove what was allowed, and by whom.
devolyn guard · audit trailGREENChain verified1,412 entries · signed · append-onlyVerifyExport- #1408a1b2c9↑ f07e31
- #1409c3d4e0↑ a1b2c9
- #1410e5f6a7↑ c3d4e0
- #14110b9c1d↑ e5f6a7
- #14127d2e4f↑ 0b9c1d
time event ref result hash 14:02:11 gate DVG-241 GREEN 14:02:37 gate DVG-240 RED 14:05:52 gate DVG-238 YELLOW 14:11:08 approval DVG-238 granted · m.okafor 14:11:19 merge DVG-238 committed Illustrative data — example content, not a customer's.
- 04YELLOW
Closed approval loop
When a change needs a human, it becomes a single-use, commit-bound approval — not a message someone forgets.
devolyn guard · approval queueYELLOWApproval queue1 waitingdeadline 00:41:12DVG-238YellowRename user_id → account_id
Blast radius: 14 files across 3 services
- requester
- agent · claude-code
- environment
- staging
- files
- 14
- fingerprint
- sha256:e5f6a7…91c0
Decision packet
- 01What changes: column rename across 3 services
- 02Why it stopped: blast-radius threshold (14 > 8)
- 03Policy that fired: blast-radius-review
reason requiredIllustrative data — example content, not a customer's.
- 05GREEN
Read-only on your code
Guard reads a pull request to verify it. It never executes your code and never writes to your repository.
github · install devolyn guardGREENDevolyn Guard would like permission to:
- MetadataRead
- ContentsRead
- Pull requestsRead · write
- ChecksRead · write
Not requested
administration · workflows · write to contents
Illustrative data — example content, not a customer's.
Trust & security
Built to be checked, not believed.
A verification product has to be verifiable itself. Every claim here is one you can check — on the GitHub install screen, or in the audit trail — rather than take from our marketing.
- Deterministic
- Parsers and explicit rules reach the verdict — no model reads your code, and your code never trains one. Same change, same verdict, every time.
- Read-only on your code
- The GitHub App reads the files in a pull request. It cannot push a commit, change a branch or alter a repository setting.
- Never executed
- Guard parses your code; it never runs it. No build, no test run, no install of your dependencies on our side.
- Tamper-evident audit
- Every decision is appended to a hash-chained, signed trail. Alter an entry and the chain fails to verify.
- Deleted on uninstall
- Remove the App and your code and everything derived from it goes with it. The audit record remains — it never held your code.
Get started
Connect GitHub. Minutes, not a deployment.
Nothing changes in your repository — no workflow file, no secrets, no tokens. Install the read-only GitHub App and the next pull request is checked.
- 01Create an account — email and a password, or Google. No card.
- 02Authorize the Devolyn Guard GitHub App on the repositories you choose.
- 03Open a pull request. Guard posts its verdict as a check.
Vision
Today, machines write code. Soon, they’ll act on their own. Devolyn is building the layer they answer to.
The name honors George Devol, who built the first industrial robot. About Devolyn →