Task: implement VM-10-002 — set VultronAS2Object.context_ default to Vultron context URI

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Background

PR #2498 added spec requirement VM-10-002 (specs/vocabulary-model.yaml):

Wire-layer classes whose _vocab_ns is VocabNamespace.VULTRON MUST
default context_ to the Vultron context URI
(https://certcc.github.io/Vultron/ns/context.jsonld) rather than the
ActivityStreams namespace URI.

ADR-0069 records the namespace URI decision. The AGENTS.md pitfall was also
added in that PR.

Consequence today: every outbound VulnerabilityCase, EmbargoEvent, etc. claims
to be a pure AS2 object. The AS2 namespace does not declare those types, so a
receiver cannot resolve them — the message is unresolvable by external
implementations.

Current state

vultron/wire/as2/vocab/base/base.py:56 still defaults context_ to
ACTIVITY_STREAMS_NS = "https://www.w3.org/ns/activitystreams" for all
wire-layer objects. VultronAS2Object (in
vultron/wire/as2/vocab/objects/base.py) does not override context_.

Verified during G02 planning (#2830): VULTRON_CONTEXT_URI appears nowhere in
vultron/, and grep -rn "VM-10-00" test/ returns nothing — VM-10-001 and
VM-10-002 are entirely unimplemented with zero test coverage.

Implementation sketch

1. Add constant in vultron/wire/as2/vocab/base/base.py:

   VULTRON_CONTEXT_URI = "https://certcc.github.io/Vultron/ns/context.jsonld"

2. Override context_ in VultronAS2Object
   (vultron/wire/as2/vocab/objects/base.py):

   context_: str = Field(
       default=VULTRON_CONTEXT_URI,
       validation_alias="@context",
       serialization_alias="@context",
   )

Acceptance criteria

1. VultronAS2Object.context_ defaults to
   "https://certcc.github.io/Vultron/ns/context.jsonld" (not the AS2
   namespace).
2. as_Base.context_ (the non-Vultron base) retains its existing
   ACTIVITY_STREAMS_NS default — do not change the base class.
3. Serialization tests in test/wire/as2/vocab/base/ verify that:
   • A VultronAS2Object subclass instance serializes with the correct
     Vultron context URI in @context.
   • An as_Base (non-Vultron) instance still serializes with the AS2
     namespace URI in @context.
4. Round-trip: from_json(obj.to_json()) preserves the Vultron @context.
5. The existing test test_as_base_context_is_as2_namespace
   (test_wire_base_hierarchy.py) continues to pass unmodified — it tests
   as_Base, which should keep the AS2 default.
6. A test asserts that every wire type whose type_ is not an ActivityStreams
   vocabulary term is annotated VocabNamespace.VULTRON. See "the _vocab_ns
   gap" below — without this, a _vocab_ns-driven fix silently skips two types.
7. Tests carry @pytest.mark.spec("VM-10-001") / @pytest.mark.spec("VM-10-002")
   so the requirements stop being uncovered.
8. uv run spec-lint passes; uv run pytest passes.

The _vocab_ns gap (found in G02, #2830)

VM-10-002 is scoped to "classes whose _vocab_ns is VocabNamespace.VULTRON". The
actual defect is "emits a Vultron-specific type alongside the bare AS2 @context",
and the two sets are not identical. Measured on main:

type_	class	_vocab_ns
CaseParticipant	as_CaseParticipant	VULTRON
CaseStatus	as_CaseStatus	VULTRON
VulnerabilityCase	as_VulnerabilityCase	VULTRON
VulnerabilityReport	as_VulnerabilityReport	VULTRON
VulnerabilityCase	VulnerabilityCaseStub	VULTRON
EmbargoEvent	as_EmbargoEvent	AS ← a literal fix misses this

as_EmbargoEvent inherits _vocab_ns = VocabNamespace.AS from as_Event and never
overrides it. But EmbargoEvent is not an ActivityStreams term, and
docs/ns/context.jsonld correctly declares it as vultron:EmbargoEvent — so
receivers still could not resolve it after a _vocab_ns-driven fix. AC-6 makes the
annotation itself testable rather than relying on each new subclass remembering to
override it.

Spec references

• VM-10-001 — outbound Vultron messages MUST declare the Vultron context URI
• VM-10-002 — VULTRON-namespace wire classes MUST default context_ to it
• ADR-0069 — docs/adr/0069-vultron-namespace-uri.md (provisional)

Files to change

• vultron/wire/as2/vocab/base/base.py — add VULTRON_CONTEXT_URI constant
• vultron/wire/as2/vocab/objects/base.py — override context_ in VultronAS2Object
• vultron/wire/as2/vocab/objects/embargo_event.py — override _vocab_ns to VULTRON
• test/wire/as2/vocab/base/ — add or extend serialization tests

Source

• PR docs: plan issue #2105 — establish Vultron vocabulary namespace URI #2498 (plan issue Concern: no stable Vultron vocabulary namespace URI to cite (circulation blocker for draft spec) #2105 — establish Vultron vocabulary namespace URI)
• Consolidated with feat(wire): override VultronAS2Object.context_ to default to Vultron namespace URI (VM-10-002) #2499 (closed as duplicate) on 2026-09-01; that issue's
  implementation snippets, round-trip test AC, and VM-10-001 reference are folded in
  above.
• _vocab_ns gap and coverage findings: G02: Wire/core boundary contract #2830 (G02),
  docs/adr/0081-wire-core-boundary-pairing-registry.md
• Blocks Generate docs/ns/context.jsonld from the vocabulary registry + CI drift check #2943 (generate docs/ns/context.jsonld + CI drift check)

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Two findings from G02 (#2830) planning that affect this task.

1. #2499 appears to be a duplicate of this issue

Both are open Tasks on Stable Protocol Vocabulary, both cite VM-10-002 and
ADR-0069, both target VultronAS2Object.context_ in
vultron/wire/as2/vocab/objects/base.py, and both prescribe the same constant. One
should be closed as a duplicate of the other — flagging rather than picking, since
either could be the survivor.

2. A literal reading of VM-10-002 leaves two types broken

VM-10-002 is scoped to "classes whose _vocab_ns is VocabNamespace.VULTRON". But
the defect is really "emits a Vultron-specific type alongside the bare AS2
@context", and the two sets are not identical.

Measured on current main — Vultron-named wire types emitting
"@context": "https://www.w3.org/ns/activitystreams":

type_	class	_vocab_ns
CaseParticipant	as_CaseParticipant	VULTRON
CaseStatus	as_CaseStatus	VULTRON
VulnerabilityCase	as_VulnerabilityCase	VULTRON
VulnerabilityReport	as_VulnerabilityReport	VULTRON
EmbargoEvent	as_EmbargoEvent	AS ← missed
VulnerabilityCase	VulnerabilityCaseStub	VULTRON

as_EmbargoEvent inherits _vocab_ns = VocabNamespace.AS from as_Event and never
overrides it, so a _vocab_ns-driven fix skips it — yet EmbargoEvent is not an
ActivityStreams term and is correctly declared as vultron:EmbargoEvent in
docs/ns/context.jsonld. Receivers still could not resolve it.

Suggestion: add an AC asserting that every wire type whose type_ is not an AS2
vocabulary term is annotated VocabNamespace.VULTRON. That makes the annotation
itself testable, rather than relying on each new subclass remembering to override it,
and it turns as_EmbargoEvent into a caught case instead of a silent one.

3. Scope note

VULTRON_CONTEXT_URI currently appears nowhere in vultron/ — VM-10-001 and
VM-10-002 are entirely unimplemented, and grep -rn "VM-10-00" test/ returns nothing,
so there is no coverage either.

#2943 (generate docs/ns/context.jsonld from the vocabulary registry + CI drift
check) is now wired blocked-by this issue — generating the context document is
premature while nothing cites it.

Context: docs/adr/0081-wire-core-boundary-pairing-registry.md, notes/wire-core-boundary.md.
Docs PR: #2931

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Claimed on branch task/2500-vm-10-002-vultron-context-uri.

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History: implementation — implement VM-10-002 VultronAS2Object context_ URI

Issue #2500 — implement VM-10-002 — set VultronAS2Object.context_ default to Vultron context URI

Implemented VM-10-001 and VM-10-002. All Vultron-specific wire objects now emit the Vultron JSON-LD context URI in @context. Changes: added VULTRON_CONTEXT_URI constant, overrode context_ on VultronAS2Object, fixed as_EmbargoEvent vocab_ns and context gap, added 9 spec-marked tests. PR: #2991