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TheRON bac6120605 deploy: the running configuration, and the identity contract

STAGING-STATE recorded mechcomp.service as delivered at deploy/mechcomp.service
on 11 SEP. The unit was real; the directory was not. It existed only on CT 100,
so the repository claimed to hold something it did not, and the only way to
answer a question about the service was to read the container. The nginx vhost
had never been committed at all.

Both imported verbatim as they ran on 12 SEP, with their host checksums proven
equal at import. A first commit of a configuration file records reality, not
intentions -- every later improvement is then a diff against a known-good
starting point rather than a rewrite nobody can check.

mechcomp.env is deliberately absent. It is the one file that is supposed to
differ between instances, it is root:mechcomp 0640 because a deployment's
bindings belong to the deployment, and a committed copy would create a second
source of truth for exactly the wrong file. ENVIRONMENT.md documents the keys.
Certificates and keys likewise.

IDENTITY-CONTRACT.md is the boundary between this application and the
membership system, and the only document here written to be read by someone who
does not work on this repository. Two systems that must agree on an interface
need it written once, somewhere both can point at.

The compiler does not authenticate anyone; it is told. CT 101 decides, against
the membership system, and sets X-Kane-Auth-Email and X-Kane-Auth-Method. They
map onto Author.email and Author.method, which already exist and are tested. The
parser's refusal to recover `verified` from text was built for this: a record
read back is always self-declared, because a file cannot attest to its own
verification.

The decision belongs at CT 101 and never at wg-pk. The hub carries twenty peers
and is estate infrastructure this project does not own, so authorisation there
would make every future adjustment an escalation and would teach a shared
transport about one project's membership roll. CT 101 already shares the service
bridge with CT 100 and CT 102.

One gated prefix, /m/. nginx gets one location block, written once. Gating a new
endpoint afterwards is choosing a URL in Python -- no proxy change, no
escalation. That cheapness makes the placement of the line reversible rather
than structural. Today it sits at export: the catalogue and composer are open,
and what requires membership is producing an artifact whose design record names
an author.

Section 6 is the part most likely to erode and is written hardest. The compiler
must never learn what a building is, what a membership level is, or that group
names exist -- including as a configuration value, which is how the leak arrives
by the side door. The test is that the membership system can rename every level
and replace its storage without a line of this repository being read.

Section 9 deletes the ACL from the roadmap rather than deferring it. The
compiler will not have a user table, a login form or a session.

Recorded openly rather than assumed: the service is world-reachable and
unauthenticated, /m/ is not yet gated, and STL export will therefore ship open.
Same posture the whole service already has. The earlier justification --
"acceptable for a development name" -- was wrong and is corrected separately:
dev.mechcomp.kane-il.us is production, dev abbreviates Mechanical Compiler
Developers, and the name is on printed material.

The inbound header strip depends on none of this and should land on its own. It
costs one directive and removes a forgery that becomes possible the moment the
headers mean anything.

2026-09-12 06:58:14 -05:00

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IDENTITY-CONTRACT.md

How the Mechanical Compiler learns who a visitor is, and the boundary that keeps it from learning anything else.


Created	2026-09-12
Status	Specified, not implemented. See §8.
Audience	This project, and whoever builds the membership system
Companions	`PROCESS.md`, `STAGING-STATE.md`, `deploy/README.md`

0. Why this document exists separately

It is the only document in this repository written to be read by someone who does not work on this repository.

The membership system is a different application, in a different container, with a different release schedule and a different author. Two systems that must agree on an interface need that interface written down once, somewhere both of them can point at. Burying it in ENVIRONMENT.md — which describes how this host is built — guarantees the other side never finds it.

The compiler is expected to catalogue a very large number of applications over a very long time. An interface that is small enough to state on one page is the only kind that survives that.

1. The shape: relying party, not integration

The compiler does not authenticate anyone. It is told.

Authorisation is decided by the reverse proxy on CT 101, against the membership system. By the time a request reaches the application, the decision is already made. The application reads an identity and acts; it never asks a question about eligibility, because it has nothing to ask the question with.

This is the same rule the project applies to physical claims. PRECISION.md puts codes and permitting out of scope — the compiler records what is true and never issues a verdict. "Who may do this" is a verdict. It belongs to whoever holds the membership roll, and not here.

The practical consequence is that the two systems share a hostname's parent domain and nothing else. Either can be rewritten entirely without the other being read.

2. The chain as it actually is

browser
  -> wg-pk            public TLS for dev.mechcomp.kane-il.us
  -> WireGuard tunnel
  -> DNAT on srv-b    scoped to the hub as source
  -> CT 101 nginx     local staging-CA TLS; DECIDES; sets the headers
  -> CT 100 :8770     the application

Two things about this that are easy to get wrong:

CT 101 does not know the public name. Its server_name is mechanical-compiler.dev.infra and its certificate is local. See deploy/README.md.

The decision belongs at CT 101, never at wg-pk. The hub carries twenty peers, is estate infrastructure this project does not own, and every change there is an escalation under PROCESS.md §7. CT 101 already shares vmbr1 with CT 100 and the membership container, so the eligibility check is a local call that never leaves the service bridge. Putting authorisation at the hub would make every future adjustment to who-may-do-what an estate change, and would teach a shared transport about one project's membership roll.

3. What crosses the boundary

Two request headers, set by CT 101, and nothing else.

Header	Meaning
`X-Kane-Auth-Email`	The identity. An email address, which is the identifier.
`X-Kane-Auth-Method`	How it was established, e.g. `kane-fabric/oidc`. Free text, recorded verbatim.

They map onto design_record.Author.email and Author.method, which exist and are tested today. When they arrive, verified becomes true and the rendered design record line changes from

author    someone@example.org   (self-declared, unverified)

author    someone@example.org   (verified: kane-fabric/oidc)

Nothing in design_record.py changes shape. The parser already refuses to recover verified from text — a record read back is always self-declared, because a file cannot attest to its own verification. That asymmetry was built for this moment.

A handle is not the identity. A person may later choose a display name. It does not replace the address and it does not travel in this contract.

4. Three invariants, all of them CT 101's job

I-1. Inbound X-Kane-Auth-* is stripped at every location, before anything else. nginx forwards headers it was given. Without the strip, any client can send X-Kane-Auth-Email and be whoever they like. This is the invariant the other two exist to support, and it is worth landing before there is anything to forge against.

I-2. CT 100 is reachable only from CT 101. The application binds 10.20.0.10:8770 on a portless service bridge with LAN traffic dropped. web/app.py defaults to loopback rather than 0.0.0.0 for the same reason: behind a proxy, binding too narrowly fails loudly as a 502, and binding too widely fails silently as an open service nobody notices.

I-3. An absent header means unauthenticated. It is never an error and never a default identity. The composer must run from a bare checkout on a machine with no proxy in front of it, and an anonymous visitor is an ordinary, expected caller. A missing header that produced a 500, or that silently became admin@somewhere, would be worse than no authentication at all.

5. One gated prefix

Everything requiring membership lives under /m/. Everything else is public.

/                the composer page            public
/api/build       build and view a section     public
/m/stl           export                       members
/m/...           anything gated later         members

nginx gets one location /m/ block, written once and not edited again. Gating a new endpoint afterwards is choosing a URL in Python — no proxy change, no shared-infrastructure change, no escalation. Ungating one is the same move in reverse.

That cheapness is the point. It means the placement of the line is a reversible decision rather than a structural one.

Where the line is today: export is gated; looking is not. The catalogue and the composer are open to anyone. What requires membership is producing an artifact that carries a design record, because the record names an author and an author only means something once somebody established who they are. The site is the shopfront; the wall goes where the claim is made.

6. What the compiler must never be told

This list is the boundary. It is short on purpose, and it is the part most likely to erode.

What a building is. Membership attaches to buildings. The compiler has no representation of one and must not acquire it.
What a membership level is. CURRENT RESIDENT, HOA MEMBER, 3D PRINTER — the compiler does not know these strings exist. By the time a request arrives, the level has already been resolved into "this request may proceed".
The membership roll. No lookup, no directory, no list of who exists.
Group names in any form, including as a configuration value. A REQUIRED_GROUP setting in the application would be the leak arriving by the side door.

If the application ever needs one of these to answer a request, the design has failed and the fix is at the proxy, not here.

The test: the membership system must be able to restructure its entire model — rename every level, change what a building is, replace its storage — without a line of this repository being read.

7. What the membership system must provide

Minimum, and deliberately not more. How it is implemented is that project's business.

An eligibility endpoint reachable from CT 101 on the service bridge, which answers a request with 2xx when the caller may proceed and 401 when not. Whatever session or token the caller carries is between that endpoint and the browser; CT 101 forwards and does not interpret.
Two response headers on a 2xx, carrying the address and the method, for CT 101 to promote onto the proxied request.

That is the whole of it. The endpoint's path, its session mechanism, its login page and its storage are not this contract's concern and should not be constrained by it.

8. Current state

Not implemented. Specified here so that it is designed once, before the endpoints that will depend on it exist.

What is true today: the service is world-reachable and unauthenticated, and /m/ is not yet gated. The first endpoint under it, STL export, will therefore ship open. That is a deliberate, recorded, temporary state and not an oversight — it is the same posture the whole service already has, and it changes when the membership system offers §7's endpoint.

An earlier version of WORK-ORDER-004 and of HANDOFF.md §4 called the open service "acceptable for a development name". That reasoning was wrong: dev.mechcomp.kane-il.us is production, dev abbreviates Mechanical Compiler Developers, and the name is on printed material. The question is carried openly instead.

I-1, the inbound strip, does not depend on any of this and should land on its own. It costs one directive and removes a forgery that would otherwise become possible the moment §3 is implemented.

9. What this removes

HANDOFF.md §4 listed an access-control layer inside the compiler as the last priority. It is deleted, not deferred. The compiler will not have an ACL, a user table, a login form, or a session. Authorisation lives at the proxy against the membership system, and an item leaves the roadmap rather than moving down it.

Persistence — the priority above it — changes shape rather than disappearing. A saved design belongs to a verified person, and the verified person now comes from outside, so it should be built knowing the identity is external.

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