docs(adr): ADR-179, a dropped forced source is recorded on the run

Documentation/Adr/Adr175ForcedSkillsBindByTheSnippetRule.rst

@@ -9,6 +9,8 @@ ADR-175: A forced skill binds by the same rule as a forced snippet
 :Amends: :ref:`ADR-166 <adr-166>` (whose "the skill half was already correct"
     held for the resume path it was judging and not for the two composition
     paths it did not look at)
+:Amended: 2026-08-19 by :ref:`ADR-179 <adr-179>` (it made the two kinds agree on
+    which sources enter a run and left the silence when one does not)
 :Authors: Netresearch DTT GmbH
 
 Context

Documentation/Adr/Adr179ADroppedForcedSourceIsRecordedOnTheRun.rst

@@ -0,0 +1,102 @@
+.. include:: /Includes.rst.txt
+
+.. _adr-179:
+
+==============================================================================
+ADR-179: A forced source that is dropped is recorded on the run
+==============================================================================
+
+:Status: Accepted
+:Date: 2026-08-19
+:Amends: :ref:`ADR-175 <adr-175>` (which made the two source kinds agree on
+    WHICH sources enter a run, and left the silence when one does not)
+:Authors: Netresearch DTT GmbH
+
+Context
+=======
+
+A run queued with a forced snippet or skill resolves that set again when it is
+dequeued. :ref:`ADR-175 <adr-175>` settled that both kinds resolve enabled-only
+there, because dequeuing is composition and a source an operator switched off
+must not enter a prompt being assembled now.
+
+What it did not settle is what the operator is told. Today: nothing. The source
+is dropped, the run proceeds without it, and the only way to notice is to
+compare the queued request against the transcript. The run does not do what the
+person who queued it asked for, and nothing says why.
+
+The silence is now uniform rather than lopsided — before ADR-175 a snippet
+disappeared and a skill survived — which is what makes it a question with one
+answer instead of two.
+
+Decision
+========
+
+**Recorded on the run, not only in a log.** A log line answers "did it happen",
+which serves support. The question an operator actually has is "why did this
+run behave differently from the one I queued", and that is asked at the run.
+The record therefore travels on :php:`RunAugmentation` from the rehydration
+that drops it, and is written through :php:`RunTrace` — the same channel
+:ref:`ADR-151 <adr-151>` uses for context accounting, so it lands in the step
+list ``Backend/AgentRun/Show.html`` already renders. No new surface is invented
+for it.
+
+**The run is not refused.** Refusing a queued run whose forced source vanished
+is defensible in principle — nothing has been sent, so refusing costs only a
+message. It is rejected because of who pays: switching off a snippet is
+routine operator maintenance, and making it fail other people's queued work
+turns a safe action into one nobody dares take. A run that proceeds without a
+source and says so is recoverable; a refused run is somebody else's incident.
+
+**"Deleted" and "switched off" read differently.** Both resolve to nothing
+today and a single "dropped" would flatten them. They are different operator
+actions with different remedies — a deactivated record can be switched back on,
+a deleted one cannot — and a reader who cannot tell them apart has to go
+looking. The record names which of the two applied, per uid.
+
+What this does not do
+=====================
+
+**It does not change which sources enter a run.** :ref:`ADR-175 <adr-175>`
+decides that and is untouched. This decides only what is said about the
+difference.
+
+**It does not touch the resume path.** :ref:`ADR-166 <adr-166>` and
+:ref:`ADR-175 <adr-175>` keep a deactivated source resolving on a resume, on
+purpose — its text is already in the transcript. Nothing is dropped there, so
+there is nothing to report, and adding a report would imply otherwise.
+
+**It does not notify anyone.** The record is readable at the run; it does not
+push. Whether a dropped source deserves a notification is the same unanswered
+question as every other pending decision in this extension, and answering it
+here for one case would settle it by accident.
+
+**It does not record a source that was never requested.** The comparison is
+against the uids the run was queued with. A caller that sends an unknown uid
+gets it reported as unresolved like any other, because from the run's side
+those are the same event.
+
+Consequences
+============
+
+An operator reading a run sees, next to the sources that were injected, the
+ones that were asked for and did not arrive, and which of the two things
+happened to each.
+
+:php:`RunAugmentation` gains a field. It is ``@internal``, so no frozen surface
+moves.
+
+The playground's synchronous send composes the same way and gains the same
+record. The queued path is where the gap between request and start is wide
+enough to matter, but a source can be switched off during a playground round
+too, and one path reporting while the other stays silent would be the
+asymmetry ADR-175 just removed.
+
+Revisit when
+============
+
+- Notifications arrive. This record deliberately does not push, and that
+  becomes a choice worth re-taking rather than an omission.
+- A third reason a forced source fails to resolve appears — a permission, a
+  workspace, a language overlay. The two-way split above would then be
+  hiding a case rather than distinguishing one.

Documentation/Adr/Index.rst

@@ -529,3 +529,4 @@ Tools
    Adr175ForcedSkillsBindByTheSnippetRule
    Adr176PerCallOutcomeSeparateFromApproval
    Adr177CallerSourceAttribution
+   Adr179ADroppedForcedSourceIsRecordedOnTheRun