diff --git a/docs/architecture/INDEX.md b/docs/architecture/INDEX.md
index 2a212636..de865395 100644
--- a/docs/architecture/INDEX.md
+++ b/docs/architecture/INDEX.md
@@ -123,6 +123,7 @@ _Documentation structure, tooling, coherence_
 | [ADR-302](./documentation/ADR-302-unified-documentation-model.md) | A unified documentation model — typed graph, ways packaging, cross-repo convergence | Accepted |
 | [ADR-303](./documentation/ADR-303-active-set-semantics-adr-archive-and-supersession-reading-for-the-adr-corpus.md) | Active-set semantics, adr archive, and supersession reading for the ADR corpus | Accepted |
 | [ADR-304](./documentation/ADR-304-typed-decision-records-the-adr-v1-contract.md) | Typed decision records: the adr/v1 contract | Accepted |
+| [ADR-305](./documentation/ADR-305-capabilities-active-at-adoption-need-no-add-decision.md) | Capabilities active at adoption need no add decision | accepted |
 
 ## Legacy (Pre-Domain Numbering)
 
diff --git a/docs/architecture/adr.yaml b/docs/architecture/adr.yaml
index e7990809..b8dfce93 100644
--- a/docs/architecture/adr.yaml
+++ b/docs/architecture/adr.yaml
@@ -60,6 +60,14 @@ capabilities:
   loop: The development loop skills (start, develop, merge, release, wrap)
   testing: The test suites and the live install fixture
 
+# Capabilities that were active when agent-ways adopted adr/v1 on the
+# adopted date. No record added them, so none needs an add decision. A change
+# on one with no prior record to name stands on the baseline. Any capability
+# declared after adoption needs an add (ADR-305).
+baseline:
+  adopted: 2026-09-27
+  capabilities: [docs, method, matching, disclosure, authoring, cli, attend, install, config, governance, loop, testing]
+
 # Retire targets name a surface; these are agent-ways' namespaces.
 surfaces:
   cli: {}
diff --git a/docs/architecture/documentation/ADR-305-capabilities-active-at-adoption-need-no-add-decision.md b/docs/architecture/documentation/ADR-305-capabilities-active-at-adoption-need-no-add-decision.md
new file mode 100644
index 00000000..92b635f3
--- /dev/null
+++ b/docs/architecture/documentation/ADR-305-capabilities-active-at-adoption-need-no-add-decision.md
@@ -0,0 +1,110 @@
+---
+contract: adr/v1
+kind: decision
+verb: change
+capability: adr
+amends: [ADR-304#6]
+basis:
+  - operator: aaronsb
+    level: guided
+    said: "Declared start active (Recommended)"
+    via: "session 2026-09-27: the operator selected option 1 of 4 on #582; the label was written by the agent"
+  - operator: aaronsb
+    level: guided
+    said: "the prior decision (the base decision) was that we could no longer test agent-ways correctly, directly on the host, it had to go into a container"
+    via: session 2026-09-27, reviewing PR #583
+  - operator: aaronsb
+    level: guided
+    said: "Accept as built (Recommended)"
+    via: "session 2026-09-27: the operator selected this for decisions 3 to 9 of the ADR-304 stack handoff, which included widening the §6 stale-citation wording; the label was written by the agent"
+  - evidence: "issue #582: ADR-186 changes a testing capability that existed before any record described it"
+  - evidence: "adr cite already warns on superseded, deprecated, rejected, abandoned and archived targets (cmd_cite.py, V1_NON_ACTIVE_STATUSES)"
+agent:
+  name: Claude
+  model: claude-opus-5-5
+considered:
+  - operator: aaronsb
+    said: "ok. so basically, I think it's the correct direction and implements the change to adr as discussed."
+    via: session 2026-09-27, reviewing PR #583
+    covers: []
+status: accepted
+date: 2026-09-27
+deciders:
+  - aaronsb
+  - Claude
+related:
+  - 304
+---
+
+# ADR-305: Capabilities active at adoption need no add decision
+
+## Summary
+
+- **Decided:** a project records under `baseline` in `adr.yaml` the date it adopted adr/v1 and the capabilities it already had then. Those capabilities need no `add` decision, and a `change` on one with no prior record to name stands on the baseline. A capability declared after adoption still needs an `add`.
+- **Trades away:** a record of why each baseline capability exists. The vocabulary line is its only description.
+- **One-way?** No. Removing a name from `baseline` restores both checks for it.
+- **Probes:** *Confident:* the outcome for a record does not depend on which other records have been migrated, since only decisions dated after adoption can be its prior, and every one of those was written as v1. *Not confident:* whether `baseline` will be used to skip an `add` for a capability that is actually new.
+- **Inversion:** at one end every capability needs a written `add`, which misstates history for a corpus that predates the contract. At the other end the vocabulary is its own authority and nothing needs an `add`, which lets new capabilities in unrecorded. This decision exempts only what existed before adoption.
+
+## Context
+
+ADR-304 §6 requires every capability in the vocabulary to have an accepted `add` decision. Most of agent-ways' capabilities (matching, attend, install, testing and others) worked long before any record described them. Migrating an old record as an `add` misstates it. ADR-186 is the example the operator gave: it moved testing off the host and into a container, which changed a testing capability that no record had added. #582 set out three options: a baseline `add` record per capability, declared capabilities starting active, and a `change` that may list several capabilities. The operator chose the second, and the agent designed the mechanism within that direction.
+
+## Decision
+
+### 1. Baseline capabilities
+
+`adr.yaml` may carry:
+
+```yaml
+baseline:
+  adopted: 2026-09-27
+  capabilities: [docs, testing]
+```
+
+`adopted` is a `YYYY-MM-DD` date. Every name in `capabilities` must be in the vocabulary. Either defect fails lint.
+
+### 2. The add check, amended
+
+The ADR-304 §6 bullet on accepted `add` decisions now reads:
+
+- Every capability in the vocabulary, except those listed in `baseline`, has an accepted `add` decision. This warns while any v0 record remains and fails after, so a corpus that is still migrating does not fail on every capability.
+
+### 3. A change on a baseline capability
+
+ADR-304 §3 requires a `change` to supersede or amend a prior decision on the same capability. A `change` with no `supersedes` or `amends` edge on a baseline capability instead stands on the baseline when either:
+
+- it is dated on or before `adopted`, or
+- no earlier decision on that capability is dated after `adopted`. Earlier means by date, then number. `constrain` decisions do not count, and neither do rejected or abandoned ones.
+
+Only decisions dated after adoption count as a prior, so migrating an older record never changes the outcome for another record. A record with no date, or a date that is not `YYYY-MM-DD`, cannot stand on the baseline.
+
+### 4. Stale citations, widened
+
+The ADR-304 §6 `doclint` bullet on superseded decisions now reads:
+
+- A citation of a superseded, deprecated, rejected, abandoned or archived record warns. For a superseded record, the warning names the successor.
+
+`adr cite` already behaves this way. The amendment brings the text in line with it.
+
+## Consequences
+
+### Positive
+
+- Migrating a record no longer requires inventing history. ADR-186 migrates as a `change` on `testing`.
+- An adopting project writes one list and one date, not one record per capability.
+
+### Negative
+
+- ADR-123 spans attend, matching and disclosure. Only `constrain` may list several capabilities, so ADR-123 stays on v0 until it is split or a rule for multi-capability changes is decided.
+- A post-adoption `change` need not name a pre-adoption record on the same capability, even after that record is migrated. The v0 prior warning still applies when it does name one.
+
+### Neutral
+
+- Projects that declare no `baseline` behave as before.
+
+## Alternatives Considered
+
+- **A baseline `add` per capability.** This keeps the history complete, but at the cost of twelve records written after the fact, each dated at adoption.
+- **A multi-capability `change`.** This would let ADR-123 migrate, but it loosens the one-change, one-capability rule, and it does not fix the missing `add` decisions.
+- **Count every v1 decision as a prior.** This was the first version of this PR. Which change counted as first then depended on the order in which records were migrated, and a frozen record could start failing when an older one migrated.
diff --git a/docs/architecture/system/ADR-186-live-integration-fixture-install-path-test-levels-and-the-tier-2-gate.md b/docs/architecture/system/ADR-186-live-integration-fixture-install-path-test-levels-and-the-tier-2-gate.md
index e44b62b1..b7ff0599 100644
--- a/docs/architecture/system/ADR-186-live-integration-fixture-install-path-test-levels-and-the-tier-2-gate.md
+++ b/docs/architecture/system/ADR-186-live-integration-fixture-install-path-test-levels-and-the-tier-2-gate.md
@@ -1,4 +1,11 @@
 ---
+contract: adr/v1
+kind: decision
+verb: change
+capability: testing
+agent: {name: Claude, model: unrecorded}
+basis:
+  - evidence: the reviews of PRs #501, #502, #504 and #508, each of which found a defect on the install path by reading the code, none of it run end to end on a clean machine
 status: Accepted
 date: 2026-09-17
 deciders:
@@ -13,6 +20,14 @@ related:
 
 # ADR-186: Live integration fixture: install-path test levels and the tier 2 gate
 
+## Summary
+
+- **Decided:** the install path is tested in a container, at two levels. Tier 1 installs and configures with no API key, on every pull request that touches the path. Tier 2 exercises a model with a key, on dispatch or a schedule only.
+- **Trades away:** job time and network dependence on tier 1, and tokens on a fixed cadence for tier 2.
+- **One-way?** No. The fixture is additive, and removing the job removes the gate and nothing else.
+- **Probes:** *Confident:* the #501 shape (the refusal, the recovery and the kept hooks) is asserted on every pull request. *Not confident:* none stated in the original record.
+- **Inversion:** at one end, a model runs on every pull request, so a fork's check passes with no secret and every pull request spends tokens. At the other end nothing runs a clean install and reviews keep finding install defects by reading code. The two tiers sit between them.
+
 ## Context
 
 The install path is the installer script, `make setup` with its prebuilt downloads, `ways reconcile` into a config directory that already holds a user's own files, and the hook scripts that Claude Code runs from the merged `settings.json`. The reviews of PRs #501, #502, #504 and #508 each found a defect on that path by reading the code, and each said the same thing: none of it had been run end to end on a clean machine.
diff --git a/hooks/ways/documentation/adr/adr-tool b/hooks/ways/documentation/adr/adr-tool
index 66fb2684..4551934d 100755
--- a/hooks/ways/documentation/adr/adr-tool
+++ b/hooks/ways/documentation/adr/adr-tool
@@ -592,6 +592,17 @@ def _str_list(value) -> Optional[list]:
 def _mapping(value) -> dict:
     return value if isinstance(value, dict) else {}
 
+def _iso_date(value) -> Optional[str]:
+    """value as a YYYY-MM-DD string, or None. YAML may load a date as one."""
+    text = str(value) if value is not None else ''
+    return text if re.fullmatch(r'\d{4}-\d{2}-\d{2}', text) else None
+
+def v1_baseline(ctx) -> tuple:
+    """(adoption date or None, set of baseline capability names)."""
+    baseline = _mapping(ctx.config.get('baseline'))
+    return (_iso_date(baseline.get('adopted')),
+            set(_str_list(baseline.get('capabilities')) or []))
+
 def v1_kinds(ctx) -> dict:
     return _mapping(ctx.config.get('kinds'))
 
@@ -700,12 +711,26 @@ def rule_v1_config_shape(ctx):
         bad("contract: adr/v1 declares no capabilities")
     if 'surfaces' in config and not isinstance(config['surfaces'], dict):
         bad("surfaces: expected a mapping of namespace to settings")
+    if 'baseline' in config:
+        baseline = config['baseline']
+        names = _str_list(baseline.get('capabilities')) if isinstance(baseline, dict) else None
+        if names is None:
+            bad("baseline: expected 'adopted' (a YYYY-MM-DD date) and 'capabilities' (a list of names)")
+        else:
+            if not _iso_date(baseline.get('adopted')):
+                bad("baseline.adopted: expected a YYYY-MM-DD date")
+            if isinstance(config.get('capabilities'), dict):
+                for name in names:
+                    if name not in config['capabilities']:
+                        bad(f"baseline: '{name}' is not in the capabilities vocabulary")
 
 @config_rule(contract=V1)
 def rule_v1_capabilities_added(ctx):
-    """Every capability in the vocabulary has an accepted `add` decision. This
-    warns while v0 records remain, so a migrating corpus is not failed on every
-    capability, and fails once migration is done (ADR-304 §6)."""
+    """Every capability in the vocabulary has an accepted `add` decision, except
+    those in `baseline`: capabilities that were active when the project
+    adopted the contract, which no record added. This warns while v0 records
+    remain, so a migrating corpus is not failed on every capability, and fails
+    once migration is done (ADR-304 §6, amended by ADR-305)."""
     added = set()
     for adr in ctx.corpus:
         if (is_v1_record(adr, ctx)
@@ -716,8 +741,9 @@ def rule_v1_capabilities_added(ctx):
     # hold the check at warning.
     migrating = any(not is_v1_record(adr, ctx) and not is_archived(adr.path)
                     for adr in ctx.corpus)
+    _, baseline = v1_baseline(ctx)
     for name in v1_capabilities(ctx):
-        if name not in added:
+        if name not in added and name not in baseline:
             ctx.config_issues.append(Issue(
                 f"capability '{name}' has no accepted add decision",
                 'warning' if migrating else 'error'))
@@ -840,11 +866,40 @@ def rule_v1_edges(adr, ctx):
             if section and not section_exists(target, section):
                 v1_issue(adr, f"{field_name}: ADR-{number} has no section '{section}'")
 
+def decision_order(adr) -> tuple:
+    """Records in decision order: by date, then number (ADR-304 §3)."""
+    base, _, part = str(adr.number or '0').partition('.')
+    return (str(adr.date or ''), int(base or 0), int(part or 0))
+
+def _stands_on_baseline(capability: str, adr, ctx) -> bool:
+    """A change with no prior edge stands on the baseline when the capability
+    is in it and either the change predates adoption, or no live decision on
+    the capability has been made since adoption before it. Only decisions
+    dated after adoption count: each was written as v1, so migrating an older
+    record never moves the answer (ADR-305)."""
+    adopted, baseline = v1_baseline(ctx)
+    when = _iso_date(adr.date)
+    if capability not in baseline or not adopted or not when:
+        return False
+    if when <= adopted:
+        return True
+    for other in ctx.corpus:
+        other_when = _iso_date(other.date)
+        if (other is not adr and is_v1_record(other, ctx)
+                and other.frontmatter.get('verb') not in (None, 'constrain')
+                and str(other.status or '').lower() not in ('rejected', 'abandoned')
+                and covers(other, capability)
+                and other_when and other_when > adopted
+                and decision_order(other) < decision_order(adr)):
+            return False
+    return True
+
 @corpus_rule(contract=V1)
 def rule_v1_change_replaces(adr, ctx):
     """A change decision supersedes or amends a prior decision on the same
     capability. When the prior covers more than this capability ('*' or a
-    list), the change amends it (ADR-304 §3)."""
+    list), the change amends it (ADR-304 §3). A change on a baseline
+    capability with no prior record to name stands on the baseline (ADR-305)."""
     if not is_v1_record(adr, ctx) or adr.frontmatter.get('verb') != 'change':
         return
     edges = []
@@ -861,6 +916,8 @@ def rule_v1_change_replaces(adr, ctx):
             continue
         if fits:
             v1_issue(adr, f"a change on '{capability}' against a broader decision amends it rather than superseding it")
+        elif not edges and _stands_on_baseline(capability, adr, ctx):
+            continue
         elif v0_priors:
             numbers = ', '.join(f"ADR-{t.number}" for t in v0_priors)
             v1_issue(adr, f"cannot confirm the prior decision on '{capability}': {numbers} is still v0", 'warning')
@@ -2220,7 +2277,7 @@ def cmd_cite(args):
             verb = adr.frontmatter.get('verb')
             if (is_v1_record(adr, ctx) and verb in ('add', 'cut')
                     and str(adr.status or '').lower() == 'accepted'):
-                order = (str(adr.date or ''), _number_order(adr.number))
+                order = decision_order(adr)
                 for capability in capability_scope(adr):
                     if capability not in latest or order >= latest[capability][0]:
                         latest[capability] = (order, adr)
@@ -2334,10 +2391,6 @@ def _cite_key(number: str) -> str:
     base = base.lstrip('0') or '0'
     return f"{base}.{part.lstrip('0') or '0'}" if part else base
 
-def _number_order(number) -> tuple:
-    base, _, part = _cite_key(number or '0').partition('.')
-    return (int(base), int(part or 0))
-
 def _cite_files(root: Path) -> list:
     """Repository files, sorted: git's view when available (tracked and
     untracked but not ignored), else a walk that prunes dependency and build
diff --git a/hooks/ways/documentation/adr/src/cmd_cite.py b/hooks/ways/documentation/adr/src/cmd_cite.py
index fe02038f..9a934c1a 100644
--- a/hooks/ways/documentation/adr/src/cmd_cite.py
+++ b/hooks/ways/documentation/adr/src/cmd_cite.py
@@ -74,7 +74,7 @@ def is_proposed(adr) -> bool:
             verb = adr.frontmatter.get('verb')
             if (is_v1_record(adr, ctx) and verb in ('add', 'cut')
                     and str(adr.status or '').lower() == 'accepted'):
-                order = (str(adr.date or ''), _number_order(adr.number))
+                order = decision_order(adr)
                 for capability in capability_scope(adr):
                     if capability not in latest or order >= latest[capability][0]:
                         latest[capability] = (order, adr)
@@ -188,10 +188,6 @@ def _cite_key(number: str) -> str:
     base = base.lstrip('0') or '0'
     return f"{base}.{part.lstrip('0') or '0'}" if part else base
 
-def _number_order(number) -> tuple:
-    base, _, part = _cite_key(number or '0').partition('.')
-    return (int(base), int(part or 0))
-
 def _cite_files(root: Path) -> list:
     """Repository files, sorted: git's view when available (tracked and
     untracked but not ignored), else a walk that prunes dependency and build
diff --git a/hooks/ways/documentation/adr/src/rules_v1.py b/hooks/ways/documentation/adr/src/rules_v1.py
index 5c7b93af..83ccb1f7 100644
--- a/hooks/ways/documentation/adr/src/rules_v1.py
+++ b/hooks/ways/documentation/adr/src/rules_v1.py
@@ -37,6 +37,17 @@ def _str_list(value) -> Optional[list]:
 def _mapping(value) -> dict:
     return value if isinstance(value, dict) else {}
 
+def _iso_date(value) -> Optional[str]:
+    """value as a YYYY-MM-DD string, or None. YAML may load a date as one."""
+    text = str(value) if value is not None else ''
+    return text if re.fullmatch(r'\d{4}-\d{2}-\d{2}', text) else None
+
+def v1_baseline(ctx) -> tuple:
+    """(adoption date or None, set of baseline capability names)."""
+    baseline = _mapping(ctx.config.get('baseline'))
+    return (_iso_date(baseline.get('adopted')),
+            set(_str_list(baseline.get('capabilities')) or []))
+
 def v1_kinds(ctx) -> dict:
     return _mapping(ctx.config.get('kinds'))
 
@@ -145,12 +156,26 @@ def bad(message):
         bad("contract: adr/v1 declares no capabilities")
     if 'surfaces' in config and not isinstance(config['surfaces'], dict):
         bad("surfaces: expected a mapping of namespace to settings")
+    if 'baseline' in config:
+        baseline = config['baseline']
+        names = _str_list(baseline.get('capabilities')) if isinstance(baseline, dict) else None
+        if names is None:
+            bad("baseline: expected 'adopted' (a YYYY-MM-DD date) and 'capabilities' (a list of names)")
+        else:
+            if not _iso_date(baseline.get('adopted')):
+                bad("baseline.adopted: expected a YYYY-MM-DD date")
+            if isinstance(config.get('capabilities'), dict):
+                for name in names:
+                    if name not in config['capabilities']:
+                        bad(f"baseline: '{name}' is not in the capabilities vocabulary")
 
 @config_rule(contract=V1)
 def rule_v1_capabilities_added(ctx):
-    """Every capability in the vocabulary has an accepted `add` decision. This
-    warns while v0 records remain, so a migrating corpus is not failed on every
-    capability, and fails once migration is done (ADR-304 §6)."""
+    """Every capability in the vocabulary has an accepted `add` decision, except
+    those in `baseline`: capabilities that were active when the project
+    adopted the contract, which no record added. This warns while v0 records
+    remain, so a migrating corpus is not failed on every capability, and fails
+    once migration is done (ADR-304 §6, amended by ADR-305)."""
     added = set()
     for adr in ctx.corpus:
         if (is_v1_record(adr, ctx)
@@ -161,8 +186,9 @@ def rule_v1_capabilities_added(ctx):
     # hold the check at warning.
     migrating = any(not is_v1_record(adr, ctx) and not is_archived(adr.path)
                     for adr in ctx.corpus)
+    _, baseline = v1_baseline(ctx)
     for name in v1_capabilities(ctx):
-        if name not in added:
+        if name not in added and name not in baseline:
             ctx.config_issues.append(Issue(
                 f"capability '{name}' has no accepted add decision",
                 'warning' if migrating else 'error'))
@@ -285,11 +311,40 @@ def rule_v1_edges(adr, ctx):
             if section and not section_exists(target, section):
                 v1_issue(adr, f"{field_name}: ADR-{number} has no section '{section}'")
 
+def decision_order(adr) -> tuple:
+    """Records in decision order: by date, then number (ADR-304 §3)."""
+    base, _, part = str(adr.number or '0').partition('.')
+    return (str(adr.date or ''), int(base or 0), int(part or 0))
+
+def _stands_on_baseline(capability: str, adr, ctx) -> bool:
+    """A change with no prior edge stands on the baseline when the capability
+    is in it and either the change predates adoption, or no live decision on
+    the capability has been made since adoption before it. Only decisions
+    dated after adoption count: each was written as v1, so migrating an older
+    record never moves the answer (ADR-305)."""
+    adopted, baseline = v1_baseline(ctx)
+    when = _iso_date(adr.date)
+    if capability not in baseline or not adopted or not when:
+        return False
+    if when <= adopted:
+        return True
+    for other in ctx.corpus:
+        other_when = _iso_date(other.date)
+        if (other is not adr and is_v1_record(other, ctx)
+                and other.frontmatter.get('verb') not in (None, 'constrain')
+                and str(other.status or '').lower() not in ('rejected', 'abandoned')
+                and covers(other, capability)
+                and other_when and other_when > adopted
+                and decision_order(other) < decision_order(adr)):
+            return False
+    return True
+
 @corpus_rule(contract=V1)
 def rule_v1_change_replaces(adr, ctx):
     """A change decision supersedes or amends a prior decision on the same
     capability. When the prior covers more than this capability ('*' or a
-    list), the change amends it (ADR-304 §3)."""
+    list), the change amends it (ADR-304 §3). A change on a baseline
+    capability with no prior record to name stands on the baseline (ADR-305)."""
     if not is_v1_record(adr, ctx) or adr.frontmatter.get('verb') != 'change':
         return
     edges = []
@@ -306,6 +361,8 @@ def rule_v1_change_replaces(adr, ctx):
             continue
         if fits:
             v1_issue(adr, f"a change on '{capability}' against a broader decision amends it rather than superseding it")
+        elif not edges and _stands_on_baseline(capability, adr, ctx):
+            continue
         elif v0_priors:
             numbers = ', '.join(f"ADR-{t.number}" for t in v0_priors)
             v1_issue(adr, f"cannot confirm the prior decision on '{capability}': {numbers} is still v0", 'warning')
diff --git a/tests/adr-golden-test.sh b/tests/adr-golden-test.sh
index f862f0fe..1b525f65 100755
--- a/tests/adr-golden-test.sh
+++ b/tests/adr-golden-test.sh
@@ -229,6 +229,39 @@ capture v1-lint-check  lint --check
 capture v1-list        list
 capture v1-view-spec   view 102
 capture v1-lint-precedent-relative lint docs/architecture/system/ADR-109-precedent-chain.md
+# Baseline capabilities (ADR-305). export joins the vocabulary as a baseline
+# capability adopted on 2025-05-10: it needs no add decision.
+baseline_fresh() {
+  fresh v1
+  edit docs/architecture/adr.yaml "s.replace('surfaces:', 'baseline:\\n  adopted: 2025-05-10\\n  capabilities: [export]\\n\\nsurfaces:', 1).replace('  search: Query over the store\\n', '  search: Query over the store\\n  export: Export from the store\\n')"
+}
+# export_change NUMBER SLUG DATE [EXTRA-FRONTMATTER-LINE]
+export_change() {
+  (cd "$WORK/repo" && printf -- '---\ncontract: adr/v1\nkind: decision\nverb: change\ncapability: export\n%sstatus: proposed\ndate: %s\ndeciders: [developer]\nagent: {name: Claude, model: m}\nbasis:\n  - evidence: export measured\n---\n\n# ADR-%s: %s\n\n## Summary\n\n- **Probes:** *Confident:* a. *Not confident:* b.\n- **Inversion:** c.\n' "${4:+$4\n}" "$3" "$1" "$2" > "docs/architecture/system/ADR-$1-$2.md")
+}
+baseline_fresh
+capture v1-lint-baseline lint
+# Malformed baseline config: a bare list, then an unknown name and a bad date.
+edit docs/architecture/adr.yaml "s.replace('baseline:\\n  adopted: 2025-05-10\\n  capabilities: [export]', 'baseline: [export]')"
+capture v1-lint-baseline-list lint
+edit docs/architecture/adr.yaml "s.replace('baseline: [export]', 'baseline:\\n  adopted: May 2025\\n  capabilities: [export, exprt]')"
+capture v1-lint-baseline-unknown lint
+# A change before adoption stands on the baseline, and so does the first
+# change after it. ADR-118 is numbered lower but dated later than ADR-119,
+# so it is the second post-adoption change and must name ADR-119.
+baseline_fresh
+export_change 117 pre-adoption-export 2025-05-09
+export_change 119 stream-exports 2025-05-20
+export_change 118 compress-exports 2025-05-22
+capture v1-lint-baseline-change lint
+edit docs/architecture/system/ADR-118-compress-exports.md "s.replace('capability: export\n', 'capability: export\nsupersedes: [ADR-119]\n')"
+capture v1-lint-baseline-change-names-prior lint
+# A rejected post-adoption change is no prior.
+edit docs/architecture/system/ADR-118-compress-exports.md "s.replace('supersedes: [ADR-119]\n', '')"
+edit docs/architecture/system/ADR-119-stream-exports.md "s.replace('status: proposed', 'status: rejected')"
+capture v1-lint-baseline-change-rejected-prior lint
+fresh v1
+fresh v1
 capture v1-cite        cite
 # The cut on search, enacted: citations of search records now fail.
 (cd "$WORK/repo" && sed -i.bak 's/^verb: cut$/verb: cut\nenacted: abcdef1/' docs/architecture/system/ADR-111-cut-search.md \
diff --git a/tests/fixtures/adr/golden/v1-lint-baseline-change-names-prior.out b/tests/fixtures/adr/golden/v1-lint-baseline-change-names-prior.out
new file mode 100644
index 00000000..d852dfdb
--- /dev/null
+++ b/tests/fixtures/adr/golden/v1-lint-baseline-change-names-prior.out
@@ -0,0 +1,30 @@
+
+Scanned: 18 ADRs
+
+Status distribution:
+  accepted: 9
+  proposed: 9
+
+Contract: adr/v1 (1 v0 records remain)
+
+────────────────────────────────────────────────────────────
+Issues found in 4 files:
+────────────────────────────────────────────────────────────
+
+docs/architecture/adr.yaml
+  ⚠️ capability 'search' has no accepted add decision
+
+docs/architecture/system/ADR-108-ingest-over-v0.md
+  ⚠️ cannot confirm the prior decision on 'ingest': ADR-110 is still v0
+
+docs/architecture/system/ADR-114-open-concern.md
+  ⚠️ open concern: Batch size may starve small tenants
+
+docs/architecture/system/ADR-118-compress-exports.md
+  ⚠️ supersedes: ADR-119 does not declare the reciprocal superseded_by: ADR-118 — one-directional links rot
+
+════════════════════════════════════════════════════════════
+Summary: 0 errors, 4 warnings
+════════════════════════════════════════════════════════════
+
+[exit 0]
diff --git a/tests/fixtures/adr/golden/v1-lint-baseline-change-rejected-prior.out b/tests/fixtures/adr/golden/v1-lint-baseline-change-rejected-prior.out
new file mode 100644
index 00000000..a9dc0d54
--- /dev/null
+++ b/tests/fixtures/adr/golden/v1-lint-baseline-change-rejected-prior.out
@@ -0,0 +1,28 @@
+
+Scanned: 18 ADRs
+
+Status distribution:
+  accepted: 9
+  proposed: 8
+  rejected: 1
+
+Contract: adr/v1 (1 v0 records remain)
+
+────────────────────────────────────────────────────────────
+Issues found in 3 files:
+────────────────────────────────────────────────────────────
+
+docs/architecture/adr.yaml
+  ⚠️ capability 'search' has no accepted add decision
+
+docs/architecture/system/ADR-108-ingest-over-v0.md
+  ⚠️ cannot confirm the prior decision on 'ingest': ADR-110 is still v0
+
+docs/architecture/system/ADR-114-open-concern.md
+  ⚠️ open concern: Batch size may starve small tenants
+
+════════════════════════════════════════════════════════════
+Summary: 0 errors, 3 warnings
+════════════════════════════════════════════════════════════
+
+[exit 0]
diff --git a/tests/fixtures/adr/golden/v1-lint-baseline-change.out b/tests/fixtures/adr/golden/v1-lint-baseline-change.out
new file mode 100644
index 00000000..a6555279
--- /dev/null
+++ b/tests/fixtures/adr/golden/v1-lint-baseline-change.out
@@ -0,0 +1,30 @@
+
+Scanned: 18 ADRs
+
+Status distribution:
+  accepted: 9
+  proposed: 9
+
+Contract: adr/v1 (1 v0 records remain)
+
+────────────────────────────────────────────────────────────
+Issues found in 4 files:
+────────────────────────────────────────────────────────────
+
+docs/architecture/adr.yaml
+  ⚠️ capability 'search' has no accepted add decision
+
+docs/architecture/system/ADR-108-ingest-over-v0.md
+  ⚠️ cannot confirm the prior decision on 'ingest': ADR-110 is still v0
+
+docs/architecture/system/ADR-114-open-concern.md
+  ⚠️ open concern: Batch size may starve small tenants
+
+docs/architecture/system/ADR-118-compress-exports.md
+  ❌ a change decision supersedes or amends a prior decision on 'export'
+
+════════════════════════════════════════════════════════════
+Summary: 1 errors, 3 warnings
+════════════════════════════════════════════════════════════
+
+[exit 0]
diff --git a/tests/fixtures/adr/golden/v1-lint-baseline-list.out b/tests/fixtures/adr/golden/v1-lint-baseline-list.out
new file mode 100644
index 00000000..0b521ce3
--- /dev/null
+++ b/tests/fixtures/adr/golden/v1-lint-baseline-list.out
@@ -0,0 +1,29 @@
+
+Scanned: 15 ADRs
+
+Status distribution:
+  accepted: 9
+  proposed: 6
+
+Contract: adr/v1 (1 v0 records remain)
+
+────────────────────────────────────────────────────────────
+Issues found in 3 files:
+────────────────────────────────────────────────────────────
+
+docs/architecture/adr.yaml
+  ❌ baseline: expected 'adopted' (a YYYY-MM-DD date) and 'capabilities' (a list of names)
+  ⚠️ capability 'search' has no accepted add decision
+  ⚠️ capability 'export' has no accepted add decision
+
+docs/architecture/system/ADR-108-ingest-over-v0.md
+  ⚠️ cannot confirm the prior decision on 'ingest': ADR-110 is still v0
+
+docs/architecture/system/ADR-114-open-concern.md
+  ⚠️ open concern: Batch size may starve small tenants
+
+════════════════════════════════════════════════════════════
+Summary: 1 errors, 4 warnings
+════════════════════════════════════════════════════════════
+
+[exit 0]
diff --git a/tests/fixtures/adr/golden/v1-lint-baseline-unknown.out b/tests/fixtures/adr/golden/v1-lint-baseline-unknown.out
new file mode 100644
index 00000000..0b300228
--- /dev/null
+++ b/tests/fixtures/adr/golden/v1-lint-baseline-unknown.out
@@ -0,0 +1,29 @@
+
+Scanned: 15 ADRs
+
+Status distribution:
+  accepted: 9
+  proposed: 6
+
+Contract: adr/v1 (1 v0 records remain)
+
+────────────────────────────────────────────────────────────
+Issues found in 3 files:
+────────────────────────────────────────────────────────────
+
+docs/architecture/adr.yaml
+  ❌ baseline.adopted: expected a YYYY-MM-DD date
+  ❌ baseline: 'exprt' is not in the capabilities vocabulary
+  ⚠️ capability 'search' has no accepted add decision
+
+docs/architecture/system/ADR-108-ingest-over-v0.md
+  ⚠️ cannot confirm the prior decision on 'ingest': ADR-110 is still v0
+
+docs/architecture/system/ADR-114-open-concern.md
+  ⚠️ open concern: Batch size may starve small tenants
+
+════════════════════════════════════════════════════════════
+Summary: 2 errors, 3 warnings
+════════════════════════════════════════════════════════════
+
+[exit 0]
diff --git a/tests/fixtures/adr/golden/v1-lint-baseline.out b/tests/fixtures/adr/golden/v1-lint-baseline.out
new file mode 100644
index 00000000..e9a6b42c
--- /dev/null
+++ b/tests/fixtures/adr/golden/v1-lint-baseline.out
@@ -0,0 +1,27 @@
+
+Scanned: 15 ADRs
+
+Status distribution:
+  accepted: 9
+  proposed: 6
+
+Contract: adr/v1 (1 v0 records remain)
+
+────────────────────────────────────────────────────────────
+Issues found in 3 files:
+────────────────────────────────────────────────────────────
+
+docs/architecture/adr.yaml
+  ⚠️ capability 'search' has no accepted add decision
+
+docs/architecture/system/ADR-108-ingest-over-v0.md
+  ⚠️ cannot confirm the prior decision on 'ingest': ADR-110 is still v0
+
+docs/architecture/system/ADR-114-open-concern.md
+  ⚠️ open concern: Batch size may starve small tenants
+
+════════════════════════════════════════════════════════════
+Summary: 0 errors, 3 warnings
+════════════════════════════════════════════════════════════
+
+[exit 0]