Heliograph

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.

you        heliograph send net-probe ────────────────▶ transportstation    picks it up within seconds, runs it           pushes status, then the log ──────────────▶ transportyou        heliograph logs --last --gaps ◀────────────

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:

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

# Linux and macOS, from a releasecurl -sSL https://github.com/heliograph-io/heliograph/releases/latest/download/heliograph-linux-amd64 \  -o /usr/local/bin/heliograph && chmod +x /usr/local/bin/heliograph
# or from sourcego install github.com/heliograph-io/heliograph/cmd/heliograph@latest

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:

/plugin marketplace add dbhq-uk/marketplace/plugin install heliograph@dbhq         # Claude Code./install-codex.sh                      # Codex, from a clone./install.sh                            # Claude Code, from a clonenpx skills add heliograph-io/heliograph       # any agent, via skills.sh

Use

heliograph bootstrap ~/transport/payments             # plant the station payloadheliograph init payments --dir ~/transport/payments   # git, the defaultheliograph plant                                      # what to send the operatorheliograph send net-probe HOSTS="sql01 sql02"         # publish a requestheliograph watch                                      # follow itheliograph logs --last                                # read the whole logheliograph logs --last --gaps                         # where it stalledheliograph doctor                                     # will this work from hereheliograph mcp                                        # serve all of the above as tools

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:

claude mcp add heliograph -- heliograph mcp

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:

$ heliograph logs --last --gapsdemo-20260906T183628Z.txt5 captured lines
1 interval(s) of 10s or more, longest first.Each is attributed to the line BEFORE it, which is what was running.
   3m12s  after  09:14:02 | Refreshing state...

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

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.go binds it to initTransports and to the station transport directories - and nothing bound this file. It is bound now, by TestReadmeTransportClaimsMatchTheCode.

The cost was not confined here: skills.dbhq.uk/heliograph deliberately 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

cmd/heliograph/         the control CLI, and `heliograph mcp`cmd/heliograph-seal/    key generation for the relay transportcmd/heliograph-site/    the static site generatorinternal/transport/     git | relay | share | bundle | objstoreinternal/bootstrap/     `heliograph bootstrap`: plants the embedded stationinternal/wire/          the request and status documents that cross the gapinternal/seal/          sign-then-encrypt, for the relayinternal/logfile/       gap analysisinternal/mcp/           JSON-RPC over stdio, no dependenciesinternal/estate/        which transport a name refers tointernal/plant/         what to send the operatorstation/bash/           the bash station: everything that runs on the far sidestation/bootstrap.sh    the no-CLI bootstrap: clone this repo, run it by handskills/heliograph/      the agent skill: drives the CLI, and nothing elsetests/                  the station's own suite, conformance contract includedsite/content/           the documentation, one source, three renderingsinfra/                  terraform: DNS, Pages, R2 statedocs/specs/             the designs, written before the code

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

ROADMAP.md is where the work stands: what heliograph is for, what works today, and the epics for now, next and later. Known defects are issues labelled type: bug. 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