Files
hq/01-RESEARCH/011-the-module-graph/analysis.md
T
jschoubben 77f3a4cea7 Consolidate: 65 decision records to 23
Every remaining cluster merged. Each was one design that had been split across
several records because it was worked out over days rather than at once.

  the node host          8 -> 1    applies not decides, depends on nothing,
                                   per operating system, root service, the
                                   launcher, episodic, what a declaration is,
                                   actions from the bundle only
  a node and how it joins 4 -> 1   what a node is, joining, the link as
                                   security boundary, the enrolment token
  modules and the graph   7 -> 1   everything is a module, no domain modules,
                                   three edges, provisioning, the core library
  substrate and control   6 -> 1   the test, seven contexts, one control plane,
    plane                          the authority is not a database, the named
                                   products, the pinned bundle
  connectivity            3 -> 1   a route is a grant, reachability declared,
                                   filter rules
  delivery                5 -> 1   reconciliation not a pipeline, artifacts,
                                   the three silos, a failed step, the verdict
  the lab                 5 -> 1   (earlier)
  how this repository     10 -> 1  (earlier)
    works

Nothing was dropped. Each consolidated record carries the reasoning of the ones
it absorbs -- the measurements, the incidents, the alternatives rejected --
because that reasoning is the only reason to keep a record at all. What is gone
is the fragmentation: eight files to read to understand tier 0, when tier 0 is
one component.

The four superseded records went too. They existed to point at their
successors, and the successors now contain what they said.

The checker made this safe. Each merge left dangling links -- 38 files after
the host merge alone -- and it named every one. Nothing was found by reading,
and a manual pass would certainly have missed some, including references inside
AGENTS.md which every session loads.
2026-08-28 20:03:24 +02:00

5.8 KiB

The graph is not missing

Measured against origin/main of the code repository, 2026-08-26. Every manifest, read through git refs rather than a checkout.

The effort was opened to ask whether the catalogue's missing structure is a graph. It is not missing. It exists, it is healthy, and three separate parts of the system already use it.

That is the finding, and it changes what is worth asking.

Finding 1 — the graph is already declared, and it is clean

manifests 126
declare a dependency on another module 64
declare a requirement on a provision 11
edges 103
declare neither 62 — 49%
cycles 0
dependencies declared but absent 0
deepest chain 5

Half the catalogue is unconnected, which matches research 005's finding that fifty modules co-change with nothing. The connected half is well formed: no cycles, nothing dangling.

Finding 2 — it is already resolved, and already used

The platform SDK carries a dependency resolver that topologically sorts modules, and it is called from three places: the tool loader at startup, the installer when syncing modules onto a node, and the delivery coordinator when expanding what a change affects.

It also already does something the effort assumed would need designing: a requirement on another module's provision is treated as an implicit edge to that module, so a consumer does not have to declare the same relationship twice.

So ordering by the graph — which ADR 0037 says the control plane will do — is not a thing to build. It is a thing to call.

Finding 3 — the most important edges in the mesh are invisible

The one place the graph is wrong, and it is wrong about the substrate.

A module that needs a database declares it like this:

provisions:
  - name: mesh-db
    provider: postgres          # ← a dependency on the postgres module
    node: <a named node>        # ← and where it must run

provider: names a module. It is a dependency, declared, in the manifest — and it sits inside provisions:, which is what a module offers. The resolver reads dependencies: and requires:, so it never sees it.

provider references that name a real module 4
invisible to the resolver 3, across 2 modules

Three edges is nothing, and they are the mesh's own database, the mesh's own broker, and the work engine's database. The most load-bearing relationships in the system are the ones the graph cannot see.

The consequence is measurable. Computing what a working mesh needs, from the declared graph:

   registry → sdk → mesh → meshware        4 modules, 4 levels

No database. No broker. A closure that is arithmetically correct and obviously wrong, and wrong for exactly one reason: a field that means depends on is not read as one.

This is 04-ISSUES/003 again, in a new place — not a key nothing reads, but a key read as something other than what it means.

Finding 4 — the resolver continues past faults it should stop on

Two behaviours, both contrary to ADR 0058:

  • A cycle warns and falls back to input order. A cycle means no correct order exists; the resolver proceeds with an arbitrary one and logs a line.
  • A dependency that does not exist warns and continues. The validation is documented as non-fatal, logged as warnings.

Neither has fired in the current catalogue — there are no cycles and nothing dangling — which is why nobody has noticed. They are latent, and they are in the component that ADR 0037 makes responsible for the ordering a host will apply without question.

Finding 5 — placement is decided in the catalogue

node: in a provision pins it to a named node, in the manifest. Two modules do this today, and they are the substrate ones.

Which node runs what is an inventory and placement decision — tier 2 by the skeleton's own test. Having it in a manifest means the catalogue decides placement, and a second node cannot provide the mesh's database without editing the module that consumes it.

What this means for the effort

The opening question — "what does the graph delete?" — has an answer: nothing, because the graph is already there. The premise was wrong, and finding that out is the effort's first result rather than a setback.

The questions that survive are narrower and answerable:

Missing declaration Manifests using it today
excludes — installing A makes B unavailable 0
a required node capability 0
an interface, with adapters providing it 0

Those are what a graph would add. What it would delete is a different and smaller list, and the honest version of it is: nothing yet.

And two defects worth fixing regardless of what else this effort concludes:

  1. provider: is a dependency edge and is not read as one. Fixing it makes the closure correct — which is what research 012 needs in order to answer what a one-node mesh requires.
  2. The resolver continues past a cycle and past a missing dependency. Both should refuse.

What was not measured

  • Whether the missing declarations would be used. Zero manifests declare exclusions or capabilities, and that is equally consistent with nobody needs them and nobody can express them. Nothing here separates those.
  • Whether the interface-and-adapter idea has a consumer. It is a good shape, and it is argued for rather than measured.
  • What the closure should be. Finding 3 says the computed one is wrong. It does not say what the right one is; that needs the fix first.