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hq/03-DESIGN/00-as-is/09-interfaces-and-observability.md
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mesh/merge-gate pass: the change touches no module of the mesh's graph
mesh/repo-check pass: THE CHANGE ALTERS ITS OWN CHECK (merge-check.sh): main's version judged it; the change's judges the pull requests after it merges; it…
mesh/delivery superseded: a newer head of the same pull request
Remove the decision records and research efforts, which the knowledge base now holds whole (issue 426)
ADR 0290 rule 9: once the import is checked record by record, hq keeps no copy.
The records and efforts are removed; every link or path to them reads "ADR NNNN" or
"research NNN"; a design's decisions: lists "ADR NNNN". 02-DECISIONS keeps a pointer
README with the reading order's six topics, which the knowledge base reads through the
records module; 01-RESEARCH keeps a pointer README. The checks drop the rules that
judged records (the knowledge base holds each at propose; checks/README.md says where)
and refuse a record written here again. Playbooks 01 and 02 and the skills write and
read records with the knowledge base's verbs.
2026-10-11 12:56:09 +02:00

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Markdown

---
layer: as-is
status: implemented
code: [hal]
updated: 2026-08-23
decisions:
- "ADR 0002"
- "ADR 0010"
---
# Interfaces and observability
How the mesh is reached, and how anyone can tell what it is doing.
## Capabilities are the primary interface
The mesh's primary interface is not a web dashboard. It is a set of **capabilities**, exposed to
a session and callable in language.
A capability is contributed by a module and is available on any node, wherever it actually
runs: local ones directly, remote ones through a stand-in created at startup that forwards over
the broker. The caller does not know the difference, and the credentials never move.
This is the mesh's stated vision made concrete — an agent states an intent and the mesh works
out which node holds the thing. It is also why a capability's **schema** is load-bearing in a
way that is easy to underestimate: a parameter name that collides with the transport's own
reserved names breaks the call, and a validation-library version mismatch has silently dropped
every argument while the call still appeared to succeed.
## The board
A web interface presents the mesh — nodes, modules, pipelines, agents, work. It is a **view**.
Its own guidance is that shared logic belongs in the mesh's library rather than inline in the
board, precisely so the board does not quietly become a second implementation of the mesh's
rules.
## Public exposure
Nodes carrying a public name run a reverse proxy as the sole entry point. A module declares the
names its interfaces answer on, portably, and the proxy's configuration is **generated** from
those declarations rather than written — generated files are marked as such and anything
hand-written beside them is left alone.
Nodes without a public role use a local equivalent with locally-trusted certificates. The
generation step degrades quietly on a node with no proxy, which is intended and is one more
place where "nothing happened" is the correct outcome and looks identical to a failure.
Certificate issuance currently always targets the public authority's production endpoint,
which consumes real quota for every experiment
([`04-ISSUES/004`](../../04-ISSUES/004-certificate-issuance-targets-production/00-report.md)).
## Health
Nodes run checks and report. The mesh's health surface answers whether things are up.
What it does **not** answer is whether they are correct, and that gap is the recurring theme of
this whole system: the deploy path reports transport rather than effect, so absence reads as
success. A check that confirms a service is running does not confirm the service is running the
code that was just deployed, and a node has been left on old code with a version marker that
had already advanced.
## Thoughts
Every node's daemon runs a periodic loop that surfaces observations from that node's own
context. They are stored in the mesh and can inform a session or trigger action.
It is the one part of the mesh that is not request-driven — the mesh noticing things rather
than being asked.
## The honest summary
Observability tells you the mesh is **up**. Establishing that it is **right** currently means
reading the operational record and checking by hand.
That is the gap the lab is designed to close
([`01-to-be/01-end-to-end-testing.md`](../01-to-be/01-end-to-end-testing.md)): a place where a
change can be run end to end and a verdict produced, cheaply enough that producing one is
routine.