# Argument-0005: Retain at Rank IV | | | | --------------- | ---------------- | | **Report Date** | 2026/07/16 | | **Submitted by**| eskimor | ## Member details - Polkadot address: `12pRzYaysQz6Tr1e78sRmu9FGB8gu8yTek9x6xwVFFAwXTM8` - Current rank: 4 - Date of initial induction: 2023/07/16 - Date of last report: 2026/01/07 - Link to last report: https://github.com/polkadot-fellows/Evaluations/pull/239 - Area(s) of Expertise/Interest: `Parachains Consensus` ## Reporting period - Start date: 2026/01/07 - End date: 2026/07/16 ## Argument The designs of the previous period moved into implementation this period - partly by me, increasingly by colleagues building on those designs. My role has shifted accordingly: driving the designs forward, implementing core pieces and reviewing/guiding the implementation work of others. ### Low-Latency Parachains: Implementation The [low-latency v2 design](https://github.com/paritytech/polkadot-sdk/pull/11413) is now being implemented by a group of engineers, coordinated via tracking issues I authored: [low-latency relay chain](https://github.com/paritytech/polkadot-sdk/issues/10883), [low-latency cumulus changes](https://github.com/paritytech/polkadot-sdk/issues/11170) and [collator protocol V4](https://github.com/paritytech/polkadot-sdk/issues/11903). Core PRs by myself here: - **[V3 Candidate Descriptor with explicit scheduling parent](https://github.com/paritytech/polkadot-sdk/pull/10472)** (merged) - the central relay chain change: decouples parachain block validity from a specific relay chain block, making parachain blocks survive relay chain forks and enabling resubmission. - **[Candidate descriptor v3 cumulus changes](https://github.com/paritytech/polkadot-sdk/pull/10742)** (merged) - parachain side: scheduling proofs, PVF validation, block builder, including e2e test. - **[Prospective parachains cleanup](https://github.com/paritytech/polkadot-sdk/pull/10650)** (merged) - architectural refactoring preparing the code base for diverging execution and scheduling contexts. [Follow-up](https://github.com/paritytech/polkadot-sdk/pull/11870) in review. Implementation work building directly on this design (selection, all merged): @iulianbarbu - [scheduling info PVF verification](https://github.com/paritytech/polkadot-sdk/pull/12097) and [scheduling signature verification](https://github.com/paritytech/polkadot-sdk/pull/12185), @alindima - [older relay parents in prospective-parachains](https://github.com/paritytech/polkadot-sdk/pull/11772) and [v3 descriptor support in the runtime](https://github.com/paritytech/polkadot-sdk/pull/11328), @mchristou - [cumulus resubmission store](https://github.com/paritytech/polkadot-sdk/pull/12091), @serban300 - [v3 find_parent() adjustments](https://github.com/paritytech/polkadot-sdk/pull/12296), @AlexandruCihodaru - [v3 descriptor support in the experimental validator](https://github.com/paritytech/polkadot-sdk/pull/11306). I reviewed most of these. ### Speculative Messaging: Design Iterations & PoC The [speculative messaging design](https://github.com/paritytech/polkadot-sdk/pull/10449) went through three major revisions this period, and is now being implemented: [v0.3 - flat per-destination commitments](https://github.com/paritytech/polkadot-sdk/pull/12579), [v0.4 - factoring out off-chain block verification](https://github.com/paritytech/polkadot-sdk/pull/12588) and [v0.5 - streams and PoV lifts](https://github.com/paritytech/polkadot-sdk/pull/12659). The off-chain block verification design that fell out of v0.4 is a component in its own right, with applications beyond messaging. Implementation has started, based on my design: @lexnv is working on a [PoC](https://github.com/paritytech/polkadot-sdk/pull/12095), @naijauser on the [primitives](https://github.com/paritytech/polkadot-sdk/pull/12368). ### Scalable Web3 Storage: From Design to Project The [storage design](https://github.com/paritytech/polkadot-sdk/pull/10731) of the last report got merged and subsequently [moved](https://github.com/paritytech/polkadot-sdk/pull/12355) into its own repository: [paritytech/web3-storage](https://github.com/paritytech/web3-storage). It is now an active implementation project with roughly ten contributors - among them @bkontur, @franciscoaguirre, @ilchu and @danielbui12 - covering the storage provider pallet, challenge protocol, provider node and S3 compatible interface. I keep refining the design as implementation questions come up, e.g. [challenge clarifications](https://github.com/paritytech/web3-storage/pull/231). ### Instant On-Demand Coretime [Fix coretime partitioning + super low latency on-demand](https://github.com/paritytech/polkadot-sdk/pull/10184) got merged: on-demand orders now appear in the claim queue in the very same block the order is placed, down from ~6 seconds. This also fixed the broken claim queue builder for partitioned coretime. ### Quality Assurance: Deterministic Simulation Testing Following up on the QA learnings from previous periods, I built [deterministic simulation based testing for subsystems](https://github.com/paritytech/polkadot-sdk/pull/12007) together with the required [clock abstraction](https://github.com/paritytech/polkadot-sdk/pull/12212). Tests declare the chain as facts and assert only on the observable contract of the subsystem. This makes them: - **implementation independent** - a subsystem may issue different queries or in different order without breaking a single test; you assert the behavior of interest, nothing else, - **deterministic** - time is driven via a mock clock, no flaky timeouts, and failures report the effect timeline instead of hanging, - **differential** - one scenario runs against both collator protocol implementations (legacy and experimental), any divergence in observable behavior locates a bug for free, - **roughly 10× smaller** than the equivalent mock-overseer tests. The framework also supports known-bug tests, enabling a test-first workflow: expected behavior gets merged and pinned before the fix exists. Writing edge-case scenarios became cheap enough that the pilot alone surfaced several production bugs (e.g. claim queue handling at [session boundaries](https://github.com/paritytech/polkadot-sdk/pull/12255)). This matters increasingly as AI contributes more code: the contract is pinned by tests that don't change with the implementation. ### Maintenance & Fixes Resilience and correctness fixes, mostly found while working on the above (all merged, several backported to stable releases): [statement distribution pruning bug](https://github.com/paritytech/polkadot-sdk/pull/11820), [rotation bug fix + simplification](https://github.com/paritytech/polkadot-sdk/pull/11967), [enforce current relay parent to be available](https://github.com/paritytech/polkadot-sdk/pull/11621), [report back when candidate is rejected](https://github.com/paritytech/polkadot-sdk/pull/11463), [UMP signal handling cleanup](https://github.com/paritytech/polkadot-sdk/pull/12240). ### Architect Role Fulfillment Per the Manifesto's requirements for Rank IV (Architect): **"Primary role in ideation and subsequent formalisation of a major protocol component"**: Low-latency parachains, speculative messaging and Web3 storage - all three designs are formalised in design documents and are in active implementation. **"Primary role in code-design and implementation"**: V3 candidate descriptor (relay chain and cumulus side) merged and deployed as node feature; deterministic simulation testing framework merged. ## Voting record | Rank | Activity threshold | Agreement threshold | My record | |------|-------------------|---------------------|-----------| | IV | 60% | 90% | I voted on 60 of 106 referenda I was eligible to vote on in this reporting period (56.6%). I voted against two: [#512](https://collectives.subsquare.io/fellowship/referenda/512), which ended up rejected (i.e. in line with the consensus), and [#565](https://collectives.subsquare.io/fellowship/referenda/565), which is still being decided. | Lifetime: [307 votes according to subsquare](https://collectives.subsquare.io/user/12pRzYaysQz6Tr1e78sRmu9FGB8gu8yTek9x6xwVFFAwXTM8/votes).