heliograph

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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 ────────────────▶ transport
station    picks it up within seconds, runs it
           pushes status, then the log ──────────────▶ transport
you        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:

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

# Linux and macOS, from a release
curl -sSL https://github.com/dbhq-uk/heliograph/releases/latest/download/heliograph-linux-amd64 \
  -o /usr/local/bin/heliograph && chmod +x /usr/local/bin/heliograph

# or from source
go install github.com/dbhq-uk/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 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 clone
npx skills add dbhq-uk/heliograph       # any agent, via skills.sh

Use

heliograph bootstrap ~/transport/payments             # plant the station payload
heliograph init payments --dir ~/transport/payments   # git, the default
heliograph plant                                      # what to send the operator
heliograph send net-probe HOSTS="sql01 sql02"         # publish a request
heliograph watch                                      # follow it
heliograph logs --last                                # read the whole log
heliograph logs --last --gaps                         # where it stalled
heliograph doctor                                     # will this work from here
heliograph 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 --gaps
demo-20260906T183628Z.txt
5 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

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	half a transport. The station side is written and complete - it fetches requests, publishes status and delivers the finished log - and the relay server is deployed. No CLI command can select it
file share, bundle, object store	control side only. The CLI implements all three; the station has no transport for any of them
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	planned: A8
documentation site	heliograph.dbhq.uk: 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 is the one the CLI drives end to end; what the others still need, and in what order, is the roadmap.

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, dbhq-uk/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 transport
cmd/heliograph-site/    the static site generator
internal/transport/     git | relay | share | bundle | objstore
internal/bootstrap/     `heliograph bootstrap`: plants the embedded station
internal/wire/          the request and status documents that cross the gap
internal/seal/          sign-then-encrypt, for the relay
internal/logfile/       gap analysis
internal/mcp/           JSON-RPC over stdio, no dependencies
internal/estate/        which transport a name refers to
internal/plant/         what to send the operator
station/bash/           the bash station: everything that runs on the far side
station/bootstrap.sh    the no-CLI bootstrap: clone this repo, run it by hand
skills/heliograph/      the agent skill: drives the CLI, and nothing else
tests/                  the station's own suite, conformance contract included
site/content/           the documentation, one source, three renderings
infra/                  terraform: DNS, Pages, R2 state
docs/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.

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

MIT (c) 2026 DBHQ Consulting Ltd