[bokelley]

Buyers can already call listAccountChanges(), but need safe boundaries between a webhook wake-up, ordered invalidation ingestion, and an acknowledged durable checkpoint. Complete the adopter-facing remainder of #2669 using the existing generated protocol types, client method, notification enums, and runtime schemas.

• Add authoritative account.change_recorded parsing with typed errors, bounded JSON input, and logical/retry/account/subscriber/resource/action identity checks. Preserve valid unknown resource/action invalidations.
• Add incompatible advisory and durable cursor types plus an acknowledged drain. Bootstrap acquires latest before authoritative snapshots, processes intervening pages before exposing a checkpoint, and reboots on structured CURSOR_EXPIRED.
• Add subscriber-preserving registration construction, expose the existing feed capability declaration, and provide public exports and migration guidance.
• Prove the packed MCP input schema has a plain object root without top-level unions and still rejects cursor/starting-position conflicts before invoking the handler. Extend the storyboard runner for persistent account-change webhook observations.

Uses merged adcontextprotocol/adcp#7516 for the bounded training-seller shared-creative/capability correction. The recipe pins immutable merge ea5498db0c611ad5b8e95618f97334f9db59e973. Seller implementation stays upstream. Adopter storage, projection/checkpoint transactions, durable feed storage (#2681), and subscription runtime (#2848) remain outside this SDK change.

Validation:

• 22 focused/packed regressions and both training integration tests pass. The unchanged published #6811 scenario passes every required phase through the merged seller's normal MCP router, with zero skips.
• Schema checks, package checks, size audit, and clean-room Node/Bun/peer-floor/declaration/browser verification pass. The file-count budget accounts for exactly 21 new artifacts; byte budgets remain unchanged (18.3 MiB packed).
• All PR CI checks pass and the exact merge head is approved. CodeQL reports no new alerts after the linear-time timestamp fix.
• Local ci:quick completed its format/type/build/fast checks with one existing local-only test hitting Node's default 4 GB heap ceiling. All 14 tests in that file pass with an 8 GB heap. Remaining slow and workspace suites were run separately and pass.
• Upstream validation includes 114 focused tests, typechecking, and 9,388 server tests passing (31 skipped). Its transient SI dependency-install failure passed on retry.

No generated adoption changes are duplicated from #2907, which was still open when this PR merged. The published rc.2 and rc.3 account-feed storyboard and schema contracts are equivalent apart from schema version IDs.

Fixes #2669

[aao-secretariat]

Ladon verdict: Approve

Approve — AdCP 3.2 account change feed (drain stream, webhook parser, subscription builder, branded cursor types, storyboard-runner support, migration guide).

No blocking findings. The reviewer verified the acknowledgement/checkpoint state machine, fail-closed drain error handling with bounded reboot, witness-preserving normalization, seller-key sanitization in error paths, JSON hardening, branded cursor type safety, and a correctly-sized minor changeset. No Critical/High/Medium findings were surfaced.

Decision trace:

• No no-auto-approve team match (HARD RULE not triggered).
• gated_paths: false → row 2 does not fire despite review_decision REVIEW_REQUIRED.
• high_risk: false → rows 3 and 5 do not fire.
• No findings of any severity → rows 1, 4, 8 do not fire.
• No prior decision → row 6 does not fire.
• Falls through to row 9 → approve.

[aao-secretariat]

Ladon verdict: Approve

Approve — clean pass, no blocking or medium findings.

Checked:

• No critical/high/medium findings in this run.
• Author is not on any no-auto-approve team.
• gated_paths: false (row 2 not triggered).
• high_risk: false; no deleted/modified high-risk paths.
• Prior decision was approve; this is a net-positive iteration adding defensive hardening on the untrusted account.change_recorded webhook path plus a test.

Reviewer notes three defensive changes: removal of a dead item !== null guard in account-change-json.ts (null handled upstream), ReDoS hardening in equalInstant (anchored date regex, O(n) trailing-zero trim, cross-offset instant equality preserved) in account-change-recorded.ts, and an 8192-digit fractional-timestamp test covering identity-preservation and mismatch. Changeset is present and consistent with wire-impact rules.

No escalation triggers fired; falls through to row 9.

[aao-secretariat]

Ladon verdict: Approve

Approve — delta pass on a prior clean approve.

The only change since the prior clean approve (head 7bd4d99) is scripts/check-package-size.mjs, where MAX_PACKED_FILE_COUNT is raised 5,995 → 6,016 (+21) to track exactly 21 new packed artifacts (five module sets × 4 + one migration guide). The arithmetic is exact, the bump is tight with no slack, byte budgets are untouched, and a changeset is present.

No critical/high/medium findings this run; no prior blockers to re-evaluate. No author team gate, gated_paths is false, high_risk is false. None of decision rows 1–8 fire → row 9 approve.

[aao-secretariat]

Ladon verdict: Approve

Approve — clean subsequent pass, no blocking or medium findings.

This is a follow-up review on a two-file delta since the prior approve (head 7bd4d99). Changes verified:

• docs/migration-account-change-feed.md: swaps a mutable PR ref for the pinned immutable SHA ea5498db — correct doc-link hygiene.
• scripts/check-package-size.mjs: bumps MAX_PACKED_FILE_COUNT 5,995 → 6,016 (+21); arithmetic and comment verified.

No new findings this run, and the prior pass had no blockers to re-evaluate. Changeset present (.changeset/quiet-account-change-drain.md) covering the src/lib/** changes.

Gate checks: gated_paths is false, so row 2 does not apply despite review_decision: REVIEW_REQUIRED. No no-auto-approve team match. high_risk false. No critical/high/medium findings. None of rows 1–8 fire → row 9 approve.