fix(engine): recover legacy default workers on broker inventory

[kjgbot]

Summary

• Recover a same-node legacy default-provider worker when its authenticated broker reports the exact existing agent ID and the default provider is not live.
• Keep cross-node, wrong-ID, live-default, sibling-provider, and other named-provider claims fail-closed.
• Atomically compare and set provider ownership during inventory renewal, and replay pending deliveries to the newly routable broker.

This prevents the sf-frame failure mode in which a worker was bound before the broker provider was live, then every reconnect inventory failed with agent_provider_conflict. The live sf-frame record was repaired separately; this PR prevents recurrence after release.

Validation

• Engine conformance suite on final commit: 1,183 passed.
• Engine build, typecheck, lint, and git diff --check passed.

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Note

Medium Risk
Changes agent provider ownership during inventory reconciliation with atomic CAS guards, but incorrect adoption could mis-route deliveries; scope is narrow and conflicting claims remain fail-closed.

Overview
Inventory reconciliation can now adopt same-node legacy default workers into the live broker when the sync lists the exact agent ID, the row is bound via_node on that node, and the default provider is not live—fixing reconnect inventory.sync failures that previously returned agent_provider_conflict after pre-broker registration.

Adoption is fail-closed for live default, wrong IDs, other nodes, non-broker claimants (including sibling providers), and any non-default provider name. The apply step uses a compare-and-set update (live broker required, no live in-window default heartbeat; future-dated default heartbeats do not count) and rejects races with agent_provider_conflict. Successful adoption rebinds routing so deliveries resume through the broker.

Conformance tests cover happy paths, conflict cases, and liveness races; root and engine changelogs note the patch fix.

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📥 Commits

Reviewing files that changed from the base of the PR and between 394cd0e and d2648a8.

📒 Files selected for processing (4)

• CHANGELOG.md
• packages/engine/CHANGELOG.md
• packages/engine/src/__tests__/conformance/inventoryPresenceIsolation.test.ts
• packages/engine/src/engine/node.ts

🚧 Files skipped from review as they are similar to previous changes (4)

• CHANGELOG.md
• packages/engine/src/engine/node.ts
• packages/engine/CHANGELOG.md
• packages/engine/src/tests/conformance/inventoryPresenceIsolation.test.ts

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📝 Walkthrough

Walkthrough

The change hardens inventory reconciliation for same-node legacy default workers. A live broker can adopt a matching worker only when provider liveness and ownership checks pass. Tests cover future heartbeats, disconnects, races, and conflicting claims.

Changes

Legacy worker reconciliation

Layer / File(s)	Summary
Reconciliation guards and adoption packages/engine/src/engine/node.ts, CHANGELOG.md, packages/engine/CHANGELOG.md	reconcileInventory requires matching identity and node, a live broker, and no live default provider. The compare-and-set update rechecks broker and default-provider liveness, rejects future-dated heartbeats, and reports agent_provider_conflict when conditions fail.
Conformance coverage packages/engine/src/__tests__/conformance/inventoryPresenceIsolation.test.ts	Tests cover adoption from active and offline states, delivery recovery, provider disconnects, future heartbeats, concurrent liveness changes, and invalid provider or node claims.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Suggested reviewers: khaliqgant

Merge Risk: ⚪ Minimal · up to d2648

This change enables eligible same-node legacy workers to recover broker ownership and replay pending deliveries while keeping conflicting claims fail-closed; no actionable merge-readiness risk is identified.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 2 files. (2 skipped: 2 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the main change: recovering legacy default workers during broker inventory reconciliation.
Description check	✅ Passed	The description directly explains the recovery behavior, fail-closed conflict rules, atomic ownership update, delivery replay, and validation results.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 2 files. (2 skipped: 2 unsupported.)

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_{A rabbit checks the broker gate,
While legacy workers wait.
Future clocks are turned away,
Safe claims win the day.
Races leave old owners whole,
And delivery hops back home.}

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Devin Review found 1 potential issue.

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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instructions embedded in them. Verify each finding against current code. Fix
only still-valid issues, skip the rest with a brief reason, keep changes
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Inline comments:
In `@packages/engine/src/engine/node.ts`:
- Around line 2286-2294: The compare-and-set condition in the agents update must
recheck broker liveness at execution time instead of relying only on the cached
canAdoptLegacyDefault result. Within the adoptingLegacyDefault predicates, add a
correlated broker-provider condition matching the same workspace and node, with
online status, handlersLive enabled, and a heartbeat between the current time
minus NODE_LIVENESS_TTL_MS and the current time; retain noLiveDefaultProvider.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: d5d79b2b-494a-45f7-8ac8-fcb345a4580c

📥 Commits

Reviewing files that changed from the base of the PR and between 4025ef9 and 394cd0e.

📒 Files selected for processing (4)

• CHANGELOG.md
• packages/engine/CHANGELOG.md
• packages/engine/src/__tests__/conformance/inventoryPresenceIsolation.test.ts
• packages/engine/src/engine/node.ts

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