Heliograph README
The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Heliograph listing page.
heliograph
Remote, captured, auditable execution on a machine you cannot log into
A free, open-source tool by DBHQ
Someone can reach the machine. You cannot, and you are the one who knows what to ask it. heliograph runs that gap as a loop rather than a relay: you publish a step, it runs on the far side, and the whole run comes back as a log with every line timestamped in UTC, whether it passed or failed.
The three ways across
heliograph carries a request to a machine you cannot log into, and brings the log back. There are three ways across the gap, and they differ in one thing: what stays held, and for how long.
Beacon. You cannot reach the machine and it cannot reach you - but you can both reach one agreed place. You leave the request there and walk away. Later the machine passes by, picks it up, runs it, and leaves the log for you to collect. Nobody is ever connected; a message waits in the middle. It is the safest of the three, because the code being run is already on the far side and can be read before anything happens - and the slowest, because you wait for the next visit.
Flare. You can reach the machine's door directly. You knock, hand over the request, wait on the step while it runs, and take the log away in the same visit. Nothing waits in the middle and no line stays open. Faster, because there is no pickup to wait for. The trade: you bring the code with you, so the machine trusts the door rather than vetting the code in advance.
Beam. You and the machine bring up a connection and hold it open. Either side can speak at any moment and the other hears it at once, until you hang up. A real session, not a message or a knock - and the most exposed, because while the line is open anything can travel down it. You turn it on deliberately and close it when you are done. It is designed, and not yet a transport you can pick.
In one line: a beacon holds a message, a flare is a single exchange, a beam holds the connection itself.
Does this sound familiar
- You have no SSH access to production, and you are not going to be given any.
- The environment is air-gapped, or behind a bastion, a jump host or a VPN you are not on.
- It is a client-owned or customer-managed estate. Only their staff can log in.
- Access is blocked by policy, not capability: restricted, change-controlled, somebody else's sign-off.
- You are on the fourth round of "can you run this and paste the output", and what came back was a screenshot of half a terminal.
- You are an AI coding agent driving an investigation, and you need the evidence rather than somebody's summary of it.
If you can just SSH in, you do not need this.
Three roles, one boundary
The boundary is the gap, and the layout states it once:
| control | your machine: the heliograph CLI, heliograph mcp, and the skill that drives them. Go, and whatever the near side can afford |
| transport | the channel: git, relay, file share, bundle, object store - all behind one interface, so the read-only gates live in one place and cannot drift per transport |
| station | the far side: station/bash/, planted into a private transport repo. Bash 4+, git and GNU coreutils. No packages, no credentials, no tunnel |
Nothing is ever installed on the far side. The station is plain text you
can read before you run - bash 4+, or PowerShell 5.1 for a Windows estate that
has no bash and will not be given any - and no Go will ever appear under
station/ beyond the one file that lets the CLI carry the payload. CI
enforces it. That constraint is the entire proposition on a locked-down
box where installing anything is its own change request.
Install
A single static binary, no runtime. Checksums are published with each release, and the binary carries the station payload it was built with.
The build is reproducible: packaging/reproduce.sh v0.4.3 rebuilds every
released artefact from the tag and arrives at the published hashes, so "the
binary in the path is the source you read" is something you check rather than
something we say. Full account, including what is not yet covered, at
docs.heliograph.io/provenance.
The agent skill - the same loop, driven from Claude Code, Codex, Cursor and friends:
Use
The operator's whole job is what plant prints: clone the transport repo,
run ./start.sh, walk away. The loop is read-only unless the operator said
otherwise: every step declares itself (# heliograph-mode: read-only or
action), one that declares neither does not run, and the station refuses an
action unless it was started with --allow-actions. It will not run as root
either.
For an agent, heliograph mcp is the same CLI as typed MCP tools:
The gates do not move. A tool call publishes a request; the station still decides whether to run it.
--gaps is the one worth knowing about. "Scan the timestamp column for gaps
before reading the content" is the most valuable instruction in the method,
and it is arithmetic:
The gap belongs to the line before it: the stamp on a line is when that line was produced, so a long interval means the operation named on the preceding line is what took the time. A log where every line carries the same timestamp is reported as an error, not as "no gaps".
Status
| control CLI over git | works, tested end to end against a stock station |
heliograph bootstrap | works: the binary plants the station it was built with |
--gaps | works |
MCP server (heliograph mcp) | works |
| bash station | in use over git: the loop, the gates, the capture, Azure hosts, Kubernetes, the Windows launcher |
| relay | works end to end. heliograph init --transport relay selects it, both stations implement it, the relay server is deployed, and TestCLIDrivesARelayStation drives the whole loop in CI |
| file share, bundle, object store | station transports exist for all three in the bash station (station/bash/transports/); init selects share, bundle and objstore. The PowerShell station carries share but not bundle or objstore |
| Azure Blob | works end to end, through drop.sh in the station payload rather than the CLI. It is what the Azure Function host uses |
| PowerShell station | ships. station/powershell/ is ~2,600 lines carrying git, share and relay, and CI runs it on a Windows runner. Design: A8 |
| documentation site | docs.heliograph.io: the CLI, the transports, and the far side - the station, the runner, steps, hosts, Azure, Windows, containers, services, secrets, security and the capture contract |
A transport that works on one side of the gap is not a transport, so this table names both sides. Git and relay are driven end to end by the CLI and proved in CI; what the others still need, and in what order, is the roadmap.
This table was wrong for some time, and the reason is worth keeping. Until 21 Sep 2026 it said relay was "half a transport" that "no CLI command can select", that the station had no transport for share, bundle or object store, and that the PowerShell station was "planned". All four were false against the code in this repository. The documentation site did not drift, because
transports_doc_test.gobinds it toinitTransportsand to the station transport directories - and nothing bound this file. It is bound now, byTestReadmeTransportClaimsMatchTheCode.The cost was not confined here:
skills.dbhq.uk/heliographdeliberately published the more conservative claim because this README contradicted the documentation site, and recorded that it would stay understated "until heliograph settles which is true". This is that settlement.
The relay
Both sides dial out over ordinary HTTPS, so an estate needs no git host, no storage account and no VNet. Hosted, and self-hostable from the same binary.
Not yet usable end to end. The station side is complete and the server is deployed; no CLI command can select it, so the near side is the missing half.
The relay cannot read your logs, and cannot make a station run anything.
That second half is the one that matters: a relay able to forge a request
would be code execution inside every estate at once. Content is end-to-end
encrypted with keys the relay never holds, and every message is signed.
Nothing bespoke - age primitives plus
Ed25519. The full account, including what DBHQ can and cannot honestly claim,
is in
docs/specs/2026-09-06-relay-encryption-design.md.
The relay server is its own repository,
heliograph-io/heliograph-relay,
because it holds no keys and must be publicly, obviously incapable of reading
anything it carries.
What the beam is, and what it costs
The beam is designed and not yet built; what follows is what it will do when it lands.
Two of the three shapes never hold a connection open. A beacon leaves a message where both sides can reach it, and needs nothing to be reachable, ever - no inbound port, no endpoint, no tunnel. A flare knocks, waits and leaves; what it does not do is hold the line open once the answer is back, and between the two of them an estate that will not have a held-open line at all still gets the whole job done.
The beam does hold a line open, live and two-way, and that is a tunnel. A blue team will read a held-open channel as one, because it is one. So it is off unless it is explicitly enabled on both ends, it is sealed and signed, and the station refuses to establish one unless it was started to allow it. Where an estate forbids a reverse connection, the beacon and the flare are the answer and nothing is lost but latency.
Every command still runs on the far side because someone with legitimate access chose to let it.
Layout
The two halves used to be separate repositories, split along Go-versus-bash
rather than along the gap, and every reader had to work out which half they
were looking at. dbhq-uk/heliograph-skill was merged in on 2026-09-08 with
its full history; the reasoning is in
docs/specs/2026-09-08-station-and-skill-merge.md.
That repository was deleted on 2026-09-17 and the name is not in use. It stayed public and archived after the merge, and an archived repository is read-only rather than unreachable: it still cloned, its install.sh still ran, and the station in it had no request-env guard at all (heliograph-cloud#274). Its history is kept privately; this repository's own history carries the merge.
Development
PLAN.md is where the work stands: what has landed, what is next,
and which defects are known and unfixed.
CONTRIBUTING.md covers working on it and
AGENTS.md is for an AI agent doing so. The skill is
skills/heliograph/SKILL.md;
docs/dev-setup.md sets it up from source with live
edits.
Licence
Apache 2.0 (c) 2026 DBHQ Consulting Ltd, and the prose under site/content/ is
CC BY 4.0. Relicensed from MIT on 2026-09-17; every commit
up to and including b689f9c stays available under MIT for ever. NOTICE
says why Apache rather than MIT, and what the change does not take away.
The relay is a separate repository and a separate licence: heliograph-relay is FSL-1.1-ALv2, fair source, converting to Apache 2.0 two years after each release. No shape is ever gated: beacon, flare and beam all work on a relay you host yourself.
Full statement, including the professional-services grant and its honest limit: https://docs.heliograph.io/licence