diff --git a/yarn-project/archiver/src/archiver-misc.test.ts b/yarn-project/archiver/src/archiver-misc.test.ts
index 6fce5a928814..14612a3bff0f 100644
--- a/yarn-project/archiver/src/archiver-misc.test.ts
+++ b/yarn-project/archiver/src/archiver-misc.test.ts
@@ -210,16 +210,13 @@ describe('Archiver misc', () => {
   describe('isPruneDueAtSlot', () => {
     /**
      * Builds a fake L2Tips. `pending` is the L1-confirmed pending checkpoint (= `tips.checkpointed`
-     * in production). `proposedCheckpoint` is set to `pending + 1` to catch any implementation that
-     * accidentally reads the local-optimistic proposed checkpoint instead of the L1-confirmed one.
+     * in production).
      */
     function makeTips(pending: CheckpointNumber, proven: CheckpointNumber): L2Tips {
       const block = { number: BlockNumber(0), hash: '0x' };
       const tip = (n: CheckpointNumber) => ({ block, checkpoint: { number: n, hash: '0x' } });
-      const proposedAhead = CheckpointNumber(Number(pending) + 1);
       return {
         proposed: block,
-        proposedCheckpoint: tip(proposedAhead),
         checkpointed: tip(pending),
         proven: tip(proven),
         finalized: tip(proven),
diff --git a/yarn-project/archiver/src/archiver-sync.test.ts b/yarn-project/archiver/src/archiver-sync.test.ts
index a5e1e2d6e886..f75422e67168 100644
--- a/yarn-project/archiver/src/archiver-sync.test.ts
+++ b/yarn-project/archiver/src/archiver-sync.test.ts
@@ -2075,11 +2075,15 @@ describe('Archiver Sync', () => {
       // Proposed checkpoint should still be set
       expect(await archiverStore.blocks.getLastProposedCheckpoint()).toBeDefined();
 
-      // Proposed tip should be ahead of the checkpointed tip
+      // Proposed checkpoint should lead the checkpointed tip
       const tips = await archiver.getL2Tips();
-      expect(tips.proposedCheckpoint.checkpoint.number).toEqual(CheckpointNumber(2));
+      const proposedCheckpointResult = await archiver.getProposedCheckpointData();
+      expect(proposedCheckpointResult).toBeDefined();
+      expect(proposedCheckpointResult!.checkpointNumber).toEqual(CheckpointNumber(2));
       expect(tips.checkpointed.checkpoint.number).toEqual(CheckpointNumber(1));
-      expect(tips.proposedCheckpoint.block.number).toBeGreaterThan(tips.checkpointed.block.number);
+      const proposedCheckpointLastBlock =
+        proposedCheckpointResult!.startBlock + proposedCheckpointResult!.blockCount - 1;
+      expect(proposedCheckpointLastBlock).toBeGreaterThan(tips.checkpointed.block.number);
     }, 15_000);
 
     it('prunes blocks and clears stale pending checkpoint when slot ends', async () => {
@@ -2142,11 +2146,9 @@ describe('Archiver Sync', () => {
       expect(await archiver.getBlockNumber()).toEqual(lastBlockInCheckpoint1);
       expect(await archiver.getCheckpointNumber()).toEqual(CheckpointNumber(1));
 
-      // Proposed checkpoint should be cleared, so proposed tip falls back to checkpointed tip
+      // Proposed checkpoint should be cleared, so no proposed checkpoint leads the checkpointed tip
       expect(await archiverStore.blocks.getLastProposedCheckpoint()).toBeUndefined();
-      const tips = await archiver.getL2Tips();
-      expect(tips.proposedCheckpoint.checkpoint.number).toEqual(tips.checkpointed.checkpoint.number);
-      expect(tips.proposedCheckpoint.block.number).toEqual(tips.checkpointed.block.number);
+      expect(await archiver.getProposedCheckpointData()).toBeUndefined();
     }, 15_000);
   });
 
diff --git a/yarn-project/archiver/src/archiver.ts b/yarn-project/archiver/src/archiver.ts
index 8ea62a41dd2d..5619c2ce0224 100644
--- a/yarn-project/archiver/src/archiver.ts
+++ b/yarn-project/archiver/src/archiver.ts
@@ -5,7 +5,7 @@ import type { L1ContractAddresses } from '@aztec/ethereum/l1-contract-addresses'
 import type { ViemPublicClient, ViemPublicDebugClient } from '@aztec/ethereum/types';
 import { BlockNumber, CheckpointNumber, EpochNumber, SlotNumber } from '@aztec/foundation/branded-types';
 import { Buffer32 } from '@aztec/foundation/buffer';
-import { merge, pick } from '@aztec/foundation/collection';
+import { merge } from '@aztec/foundation/collection';
 import { Fr } from '@aztec/foundation/curves/bn254';
 import { EthAddress } from '@aztec/foundation/eth-address';
 import { type Logger, createLogger } from '@aztec/foundation/log';
@@ -435,19 +435,23 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
     const tips = await this.getL2Tips();
     const now = BigInt(this.dateProvider.nowInSeconds());
 
+    // Frontier block covered by a proposed (or, falling back, confirmed) checkpoint. Blocks beyond it
+    // have no enclosing checkpoint proposal and are the orphan-pruning candidates.
+    const proposedCheckpointBlockNumber = await this.stores.blocks.getProposedCheckpointL2BlockNumber();
+
     // The proposed tip is a proposed-checkpointed block, so there are no orphan proposed blocks to prune
-    if (tips.proposedCheckpoint.block.number === tips.proposed.number) {
-      this.log.trace(
-        `No orphan proposed blocks to prune: proposed tip ${tips.proposed.number} is checkpointed`,
-        pick(tips, 'proposed', 'proposedCheckpoint'),
-      );
+    if (proposedCheckpointBlockNumber === tips.proposed.number) {
+      this.log.trace(`No orphan proposed blocks to prune: proposed tip ${tips.proposed.number} is checkpointed`, {
+        proposed: tips.proposed,
+        proposedCheckpointBlockNumber,
+      });
       return;
     }
 
     // Load the blocks that are candidates for pruning (ie blocks without a proposed checkpoint covering them)
     const blocksWithoutProposedCheckpoint = await this.stores.blocks.getBlocksData({
-      from: BlockNumber(tips.proposedCheckpoint.block.number + 1),
-      limit: tips.proposed.number - tips.proposedCheckpoint.block.number,
+      from: BlockNumber(proposedCheckpointBlockNumber + 1),
+      limit: tips.proposed.number - proposedCheckpointBlockNumber,
     });
 
     // Iterate through them in order, the first one with a slot that should have received a proposed checkpoint
diff --git a/yarn-project/archiver/src/store/block_store.test.ts b/yarn-project/archiver/src/store/block_store.test.ts
index d7b3eb65d62e..31dbb3fe47a6 100644
--- a/yarn-project/archiver/src/store/block_store.test.ts
+++ b/yarn-project/archiver/src/store/block_store.test.ts
@@ -13,7 +13,6 @@ import {
   BlockHash,
   CommitteeAttestation,
   EthAddress,
-  GENESIS_BLOCK_HEADER_HASH,
   L2Block,
   type ValidateCheckpointResult,
 } from '@aztec/stdlib/block';
@@ -40,7 +39,6 @@ import {
   makeStateForBlock,
 } from '../test/mock_structs.js';
 import { BlockStore } from './block_store.js';
-import { L2TipsCache } from './l2_tips_cache.js';
 
 async function addProposedBlocks(
   blockStore: BlockStore,
@@ -2627,26 +2625,19 @@ describe('BlockStore', () => {
     });
   });
 
-  describe('L2TipsCache proposedCheckpoint', () => {
-    it('returns proposedCheckpoint equal to checkpointed when no pending exists', async () => {
-      // Add checkpoint 1 with blocks 1-3
+  describe('getLastProposedCheckpoint', () => {
+    it('returns undefined when there is no pending checkpoint', async () => {
+      // Add checkpoint 1 with blocks 1-3; confirmation deletes any matching proposed entry.
       const checkpoint1 = makePublishedCheckpoint(
         await Checkpoint.random(CheckpointNumber(1), { numBlocks: 3, startBlockNumber: 1 }),
         10,
       );
       await blockStore.addCheckpoints([checkpoint1]);
 
-      const l2TipsCache = new L2TipsCache(blockStore, GENESIS_BLOCK_HEADER_HASH);
-      const tips = await l2TipsCache.getL2Tips();
-
-      // proposedCheckpoint should always be defined
-      expect(tips.proposedCheckpoint).toBeDefined();
-      // With no proposed checkpoint, it should equal the checkpointed tip
-      expect(tips.proposedCheckpoint!.block.number).toBe(tips.checkpointed.block.number);
-      expect(tips.proposedCheckpoint!.checkpoint.number).toBe(tips.checkpointed.checkpoint.number);
+      expect(await blockStore.getLastProposedCheckpoint()).toBeUndefined();
     });
 
-    it('returns proposedCheckpoint ahead of checkpointed when pending is set', async () => {
+    it('returns the leading proposed checkpoint payload', async () => {
       // Add checkpoint 1
       const checkpoint1 = makePublishedCheckpoint(
         await Checkpoint.random(CheckpointNumber(1), { numBlocks: 1, startBlockNumber: 1 }),
@@ -2663,21 +2654,23 @@ describe('BlockStore', () => {
       await blockStore.addProposedBlock(block2, { force: true });
 
       // Set proposed checkpoint
+      const header = CheckpointHeader.empty();
       await blockStore.addProposedCheckpoint({
         checkpointNumber: CheckpointNumber(2),
-        header: CheckpointHeader.empty(),
+        header,
         startBlock: BlockNumber(2),
         blockCount: 1,
         totalManaUsed: 100n,
         feeAssetPriceModifier: 50n,
       });
 
-      const l2TipsCache = new L2TipsCache(blockStore, GENESIS_BLOCK_HEADER_HASH);
-      const tips = await l2TipsCache.getL2Tips();
-
-      expect(tips.proposedCheckpoint).toBeDefined();
-      expect(tips.proposedCheckpoint!.block.number).toBeGreaterThan(tips.checkpointed.block.number);
-      expect(tips.proposedCheckpoint!.checkpoint.number).toBeGreaterThan(tips.checkpointed.checkpoint.number);
+      const proposedCheckpoint = await blockStore.getLastProposedCheckpoint();
+      expect(proposedCheckpoint).toBeDefined();
+      // Callers derive the tip from the payload: last block = startBlock + blockCount - 1.
+      expect(proposedCheckpoint!.checkpointNumber).toBe(CheckpointNumber(2));
+      expect(proposedCheckpoint!.startBlock).toBe(BlockNumber(2));
+      expect(proposedCheckpoint!.blockCount).toBe(1);
+      expect(proposedCheckpoint!.totalManaUsed).toBe(100n);
     });
   });
 
diff --git a/yarn-project/archiver/src/store/block_store.ts b/yarn-project/archiver/src/store/block_store.ts
index 1901119016c4..c1615ef601e5 100644
--- a/yarn-project/archiver/src/store/block_store.ts
+++ b/yarn-project/archiver/src/store/block_store.ts
@@ -1167,14 +1167,13 @@ export class BlockStore {
   }
 
   /**
-   * Resolves all five L2 chain tips (proposed, proposedCheckpoint, checkpointed, proven, finalized)
-   * in a single read-only transaction so the snapshot is internally consistent. Each underlying
-   * record is read at most once: latest block, latest confirmed checkpoint, and latest pending
-   * checkpoint are each loaded directly (no separate "find the number, then look up data" hop),
-   * the proven/finalized checkpoint singletons are read once and their storage entries are
-   * reused if they coincide with the latest checkpoint, and per-tip block hashes are deduped
-   * when two tips land on the same block (e.g. finalized == proven, or proposedCheckpoint falls
-   * back to checkpointed when no pending checkpoint exists).
+   * Resolves all four L2 chain tips (proposed, checkpointed, proven, finalized) in a single
+   * read-only transaction so the snapshot is internally consistent. Each underlying record is
+   * read at most once: latest block and latest confirmed checkpoint are loaded directly (no
+   * separate "find the number, then look up data" hop), the proven/finalized checkpoint
+   * singletons are read once and their storage entries are reused if they coincide with the
+   * latest checkpoint, and per-tip block hashes are deduped when two tips land on the same block
+   * (e.g. finalized == proven).
    *
    * The result is guaranteed to satisfy `finalized <= proven <= checkpointed <= proposed` (by
    * block number). Genesis is represented by `(INITIAL_L2_BLOCK_NUM - 1)` and the supplied
@@ -1197,9 +1196,6 @@ export class BlockStore {
 
       // Load latest block and checkpoint entries
       const [latestBlockEntry] = await toArray(this.#blocks.entriesAsync({ reverse: true, limit: 1 }));
-      const [proposedCheckpointEntry] = await toArray(
-        this.#proposedCheckpoints.entriesAsync({ reverse: true, limit: 1 }),
-      );
       const [latestCheckpointEntry] = await toArray(this.#checkpoints.entriesAsync({ reverse: true, limit: 1 }));
       const latestCheckpointNumber = latestCheckpointEntry
         ? CheckpointNumber(latestCheckpointEntry[0])
@@ -1285,14 +1281,6 @@ export class BlockStore {
       const provenTip = await buildTipFromCheckpoint(provenCheckpoint);
       const finalizedTip = await buildTipFromCheckpoint(finalizedCheckpoint);
 
-      // Proposed checkpoint falls back to the checkpoint tip if it's not set. And if local storage is
-      // inconsistent and the proposed checkpoint is behind the checkpointed tip, we patch that and
-      // report the checkpointed tip as the proposed checkpoint to maintain the invariant.
-      const proposedCheckpointTip =
-        proposedCheckpointEntry === undefined || proposedCheckpointEntry[0] <= latestCheckpointNumber
-          ? checkpointedTip
-          : await buildTipFromCheckpoint(proposedCheckpointEntry[1]);
-
       // A checkpointed block past the latest stored block would mean a checkpoint
       // references blocks that aren't in blocks.
       if (proposedBlockId.number < checkpointedTip.block.number) {
@@ -1304,11 +1292,10 @@ export class BlockStore {
       // Assert that checkpoint numbers are increasing
       if (
         finalizedTip.checkpoint.number > provenTip.checkpoint.number ||
-        provenTip.checkpoint.number > checkpointedTip.checkpoint.number ||
-        checkpointedTip.checkpoint.number > proposedCheckpointTip.checkpoint.number
+        provenTip.checkpoint.number > checkpointedTip.checkpoint.number
       ) {
         throw new Error(
-          `Inconsistent checkpoint numbers in chain tips: finalized=${finalizedTip.checkpoint.number} proven=${provenTip.checkpoint.number} checkpointed=${checkpointedTip.checkpoint.number} proposed=${proposedCheckpointTip.checkpoint.number}`,
+          `Inconsistent checkpoint numbers in chain tips: finalized=${finalizedTip.checkpoint.number} proven=${provenTip.checkpoint.number} checkpointed=${checkpointedTip.checkpoint.number}`,
         );
       }
 
@@ -1316,17 +1303,15 @@ export class BlockStore {
       if (
         finalizedTip.block.number > provenTip.block.number ||
         provenTip.block.number > checkpointedTip.block.number ||
-        checkpointedTip.block.number > proposedCheckpointTip.block.number ||
-        proposedCheckpointTip.block.number > proposedBlockId.number
+        checkpointedTip.block.number > proposedBlockId.number
       ) {
         throw new Error(
-          `Inconsistent block numbers in chain tips: finalized=${finalizedTip.block.number} proven=${provenTip.block.number} checkpointed=${checkpointedTip.block.number} proposedCheckpoint=${proposedCheckpointTip.block.number} proposed=${proposedBlockId.number}`,
+          `Inconsistent block numbers in chain tips: finalized=${finalizedTip.block.number} proven=${provenTip.block.number} checkpointed=${checkpointedTip.block.number} proposed=${proposedBlockId.number}`,
         );
       }
 
       return {
         proposed: proposedBlockId,
-        proposedCheckpoint: proposedCheckpointTip,
         checkpointed: checkpointedTip,
         proven: provenTip,
         finalized: finalizedTip,
diff --git a/yarn-project/archiver/src/test/mock_l1_to_l2_message_source.ts b/yarn-project/archiver/src/test/mock_l1_to_l2_message_source.ts
index d2edd93167d7..f3b72a1c940f 100644
--- a/yarn-project/archiver/src/test/mock_l1_to_l2_message_source.ts
+++ b/yarn-project/archiver/src/test/mock_l1_to_l2_message_source.ts
@@ -44,7 +44,6 @@ export class MockL1ToL2MessageSource implements L1ToL2MessageSource {
       checkpointed: tip,
       proven: tip,
       finalized: tip,
-      proposedCheckpoint: tip,
     });
   }
 }
diff --git a/yarn-project/archiver/src/test/mock_l2_block_source.ts b/yarn-project/archiver/src/test/mock_l2_block_source.ts
index 312c35e61c07..a9cee47f922f 100644
--- a/yarn-project/archiver/src/test/mock_l2_block_source.ts
+++ b/yarn-project/archiver/src/test/mock_l2_block_source.ts
@@ -55,7 +55,6 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
   private provenBlockNumber: number = 0;
   private finalizedBlockNumber: number = 0;
   private checkpointedBlockNumber: number = 0;
-  private proposedCheckpointBlockNumber: number = 0;
 
   private initialHeader: BlockHeader = BlockHeader.empty();
   private initialHeaderHash: BlockHash = GENESIS_BLOCK_HEADER_HASH;
@@ -164,7 +163,6 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
     });
     // Keep tip numbers consistent with remaining blocks.
     this.checkpointedBlockNumber = Math.min(this.checkpointedBlockNumber, maxBlockNum);
-    this.proposedCheckpointBlockNumber = Math.min(this.proposedCheckpointBlockNumber, maxBlockNum);
     this.provenBlockNumber = Math.min(this.provenBlockNumber, maxBlockNum);
     this.finalizedBlockNumber = Math.min(this.finalizedBlockNumber, maxBlockNum);
     this.log.verbose(`Removed ${numBlocks} blocks from the mock L2 block source`);
@@ -181,17 +179,9 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
     this.finalizedBlockNumber = finalizedBlockNumber;
   }
 
-  public setProposedCheckpointBlockNumber(blockNumber: number) {
-    this.proposedCheckpointBlockNumber = blockNumber;
-  }
-
   public setCheckpointedBlockNumber(checkpointedBlockNumber: number) {
     const prevCheckpointed = this.checkpointedBlockNumber;
     this.checkpointedBlockNumber = checkpointedBlockNumber;
-    // Proposed checkpoint is always at least as advanced as checkpointed
-    if (this.proposedCheckpointBlockNumber < checkpointedBlockNumber) {
-      this.proposedCheckpointBlockNumber = checkpointedBlockNumber;
-    }
     // Auto-create single-block checkpoints for newly checkpointed blocks that don't have one yet.
     // This handles blocks added via addProposedBlocks that are now being marked as checkpointed.
     const newCheckpoints: Checkpoint[] = [];
@@ -255,10 +245,6 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
     return block ? block.header.globalVariables.blockNumber : undefined;
   }
 
-  public getProposedCheckpointL2BlockNumber() {
-    return Promise.resolve(BlockNumber(this.proposedCheckpointBlockNumber));
-  }
-
   public getCheckpoint(query: CheckpointQuery): Promise<PublishedCheckpoint | undefined> {
     const checkpoint = this.resolveCheckpointQuery(query);
     if (!checkpoint) {
@@ -373,19 +359,17 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
   }
 
   async getL2Tips(): Promise<L2Tips> {
-    const [latest, proven, finalized, checkpointed, proposedCheckpoint] = [
+    const [latest, proven, finalized, checkpointed] = [
       await this.getBlockNumber(),
       this.provenBlockNumber,
       this.finalizedBlockNumber,
       this.checkpointedBlockNumber,
-      await this.getProposedCheckpointL2BlockNumber(),
     ] as const;
 
     const latestBlock = this.l2Blocks[latest - 1];
     const provenBlock = this.l2Blocks[proven - 1];
     const finalizedBlock = this.l2Blocks[finalized - 1];
     const checkpointedBlock = this.l2Blocks[checkpointed - 1];
-    const proposedCheckpointBlock = this.l2Blocks[proposedCheckpoint - 1];
 
     // For genesis tips (block number 0) report the dynamic initial header hash so consumers
     // running L2BlockStream against this mock agree at block 0 with their local tip store.
@@ -413,10 +397,6 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
       number: BlockNumber(checkpointed),
       hash: await tipHash(checkpointedBlock, checkpointed),
     };
-    const proposedCheckpointBlockId = {
-      number: BlockNumber(proposedCheckpoint),
-      hash: await tipHash(proposedCheckpointBlock, proposedCheckpoint),
-    };
 
     const makeTipId = (blockId: typeof latestBlockId) => {
       const checkpointNumber = this.findCheckpointNumberForBlock(blockId.number) ?? CheckpointNumber(0);
@@ -435,7 +415,6 @@ export class MockL2BlockSource implements L2BlockSource, ContractDataSource {
       checkpointed: makeTipId(checkpointedBlockId),
       proven: makeTipId(provenBlockId),
       finalized: makeTipId(finalizedBlockId),
-      proposedCheckpoint: makeTipId(proposedCheckpointBlockId),
     };
   }
 
diff --git a/yarn-project/aztec-node/src/aztec-node/register_node_rpc_handlers.test.ts b/yarn-project/aztec-node/src/aztec-node/register_node_rpc_handlers.test.ts
index dd71b0e627ce..d35a9d531ddc 100644
--- a/yarn-project/aztec-node/src/aztec-node/register_node_rpc_handlers.test.ts
+++ b/yarn-project/aztec-node/src/aztec-node/register_node_rpc_handlers.test.ts
@@ -6,19 +6,15 @@ import {
   createNamespacedSafeJsonRpcServer,
   startHttpRpcServer,
 } from '@aztec/foundation/json-rpc/server';
-import {
-  AztecNodeAdminApiSchema,
-  AztecNodeApiSchema,
-  AztecNodeDebugApiSchema,
-  type ChainTips,
-} from '@aztec/stdlib/interfaces/client';
+import type { L2Tips } from '@aztec/stdlib/block';
+import { AztecNodeAdminApiSchema, AztecNodeApiSchema, AztecNodeDebugApiSchema } from '@aztec/stdlib/interfaces/client';
 import { P2PApiSchema } from '@aztec/stdlib/interfaces/server';
 import type { ApiSchemaFor } from '@aztec/stdlib/schemas';
 
 import { registerAztecNodeRpcHandlers } from './register_node_rpc_handlers.js';
 import type { AztecNodeService } from './server.js';
 
-type GetChainTipsOnly = { getChainTips(): Promise<ChainTips> };
+type GetChainTipsOnly = { getChainTips(): Promise<L2Tips> };
 
 const GetChainTipsOnlySchema: ApiSchemaFor<GetChainTipsOnly> = {
   getChainTips: AztecNodeApiSchema.getChainTips,
@@ -28,7 +24,7 @@ const p2p = {};
 
 const mockNode = {
   getP2P: () => p2p,
-  getChainTips(): Promise<ChainTips> {
+  getChainTips(): Promise<L2Tips> {
     const tipId = {
       block: { number: BlockNumber(1), hash: `0x01` },
       checkpoint: { number: CheckpointNumber(1), hash: `0x01` },
@@ -90,7 +86,7 @@ describe('registerAztecNodeRpcHandlers', () => {
       headers: { 'content-type': 'application/json' },
       body: jsonStringify({ jsonrpc: '2.0', id: 1, method: 'node_getChainTips', params: [] }),
     });
-    const body = (await response.json()) as { result: ChainTips };
+    const body = (await response.json()) as { result: L2Tips };
     expect(body.result).toEqual(expected);
 
     httpServer.close();
diff --git a/yarn-project/aztec-node/src/aztec-node/server.test.ts b/yarn-project/aztec-node/src/aztec-node/server.test.ts
index 8d84ab641270..24d6df5b158f 100644
--- a/yarn-project/aztec-node/src/aztec-node/server.test.ts
+++ b/yarn-project/aztec-node/src/aztec-node/server.test.ts
@@ -744,16 +744,14 @@ describe('aztec node', () => {
       const checkpointNumber = CheckpointNumber(1);
       const proposedCheckpointBlockNumber = BlockNumber(9);
       const targetSlot = SlotNumber(10);
-      l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({
-          proposed: proposedCheckpointBlockNumber,
-          proposedCheckpoint: checkpointNumber,
-          proposedCheckpointBlock: proposedCheckpointBlockNumber,
+      l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposed: proposedCheckpointBlockNumber }));
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue(
+        makeProposedCheckpoint({
+          checkpointNumber,
+          blockNumber: proposedCheckpointBlockNumber,
+          slotNumber: SlotNumber(9),
         }),
       );
-      l2BlockSource.getBlockData.mockResolvedValue(
-        makeSimulationBlockData(proposedCheckpointBlockNumber, SlotNumber(9), checkpointNumber),
-      );
       mockNextL1Slot(SlotNumber(5));
       globalVariablesBuilder.buildCheckpointGlobalVariables.mockResolvedValue({
         chainId,
@@ -767,7 +765,7 @@ describe('aztec node', () => {
 
       await expect(node.simulatePublicCalls(tx)).rejects.toThrow();
 
-      expect(l2BlockSource.getBlockData).toHaveBeenCalledWith({ number: proposedCheckpointBlockNumber });
+      // Slot is read from the proposed checkpoint payload header, so no block fetch is needed for it.
       expect(globalVariablesBuilder.buildGlobalVariables).not.toHaveBeenCalled();
       expect(globalVariablesBuilder.buildCheckpointGlobalVariables).toHaveBeenCalledWith(
         EthAddress.ZERO,
@@ -781,16 +779,14 @@ describe('aztec node', () => {
       const checkpointNumber = CheckpointNumber(1);
       const proposedCheckpointBlockNumber = BlockNumber(9);
       const targetSlot = SlotNumber(12);
-      l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({
-          proposed: proposedCheckpointBlockNumber,
-          proposedCheckpoint: checkpointNumber,
-          proposedCheckpointBlock: proposedCheckpointBlockNumber,
+      l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposed: proposedCheckpointBlockNumber }));
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue(
+        makeProposedCheckpoint({
+          checkpointNumber,
+          blockNumber: proposedCheckpointBlockNumber,
+          slotNumber: SlotNumber(9),
         }),
       );
-      l2BlockSource.getBlockData.mockResolvedValue(
-        makeSimulationBlockData(proposedCheckpointBlockNumber, SlotNumber(9), checkpointNumber),
-      );
       mockNextL1Slot(targetSlot);
       globalVariablesBuilder.buildCheckpointGlobalVariables.mockResolvedValue({
         chainId,
@@ -804,7 +800,6 @@ describe('aztec node', () => {
 
       await expect(node.simulatePublicCalls(tx)).rejects.toThrow();
 
-      expect(l2BlockSource.getBlockData).toHaveBeenCalledWith({ number: proposedCheckpointBlockNumber });
       expect(globalVariablesBuilder.buildGlobalVariables).not.toHaveBeenCalled();
       expect(globalVariablesBuilder.buildCheckpointGlobalVariables).toHaveBeenCalledWith(
         EthAddress.ZERO,
@@ -819,24 +814,17 @@ describe('aztec node', () => {
       const proposedCheckpointBlockNumber = BlockNumber(9);
       const latestProposedBlockNumber = BlockNumber(12);
       const targetSlot = SlotNumber(12);
-      l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({
-          proposed: latestProposedBlockNumber,
-          proposedCheckpoint: checkpointNumber,
-          proposedCheckpointBlock: proposedCheckpointBlockNumber,
+      l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposed: latestProposedBlockNumber }));
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue(
+        makeProposedCheckpoint({
+          checkpointNumber,
+          blockNumber: proposedCheckpointBlockNumber,
+          slotNumber: SlotNumber(9),
         }),
       );
-      l2BlockSource.getBlockData.mockImplementation(query => {
-        if (!('number' in query)) {
-          return Promise.resolve(undefined);
-        }
-        if (query.number === proposedCheckpointBlockNumber) {
-          return Promise.resolve(
-            makeSimulationBlockData(proposedCheckpointBlockNumber, SlotNumber(9), checkpointNumber),
-          );
-        }
-        return Promise.resolve(makeSimulationBlockData(latestProposedBlockNumber, targetSlot, checkpointNumber));
-      });
+      l2BlockSource.getBlockData.mockResolvedValue(
+        makeSimulationBlockData(latestProposedBlockNumber, targetSlot, checkpointNumber),
+      );
       mockNextL1Slot(SlotNumber(5));
       globalVariablesBuilder.buildCheckpointGlobalVariables.mockResolvedValue({
         chainId,
@@ -850,7 +838,7 @@ describe('aztec node', () => {
 
       await expect(node.simulatePublicCalls(tx)).rejects.toThrow();
 
-      expect(l2BlockSource.getBlockData).toHaveBeenCalledWith({ number: proposedCheckpointBlockNumber });
+      // The latest proposed block is ahead of the proposed checkpoint, so its slot is fetched.
       expect(l2BlockSource.getBlockData).toHaveBeenCalledWith({ number: latestProposedBlockNumber });
       expect(globalVariablesBuilder.buildGlobalVariables).not.toHaveBeenCalled();
       expect(globalVariablesBuilder.buildCheckpointGlobalVariables).toHaveBeenCalledWith(
@@ -866,11 +854,12 @@ describe('aztec node', () => {
       const proposedCheckpointBlockNumber = BlockNumber(9);
       const latestProposedBlockNumber = BlockNumber(12);
       const targetSlot = SlotNumber(13);
-      l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({
-          proposed: latestProposedBlockNumber,
-          proposedCheckpoint: checkpointNumber,
-          proposedCheckpointBlock: proposedCheckpointBlockNumber,
+      l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposed: latestProposedBlockNumber }));
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue(
+        makeProposedCheckpoint({
+          checkpointNumber,
+          blockNumber: proposedCheckpointBlockNumber,
+          slotNumber: SlotNumber(9),
         }),
       );
       l2BlockSource.getBlockData.mockResolvedValue(undefined);
@@ -887,7 +876,7 @@ describe('aztec node', () => {
 
       await expect(node.simulatePublicCalls(tx)).rejects.toThrow();
 
-      expect(l2BlockSource.getBlockData).toHaveBeenCalledWith({ number: proposedCheckpointBlockNumber });
+      // Latest proposed block slot is unavailable; falls back to the next L1 timestamp slot.
       expect(l2BlockSource.getBlockData).toHaveBeenCalledWith({ number: latestProposedBlockNumber });
       expect(globalVariablesBuilder.buildGlobalVariables).not.toHaveBeenCalled();
       expect(globalVariablesBuilder.buildCheckpointGlobalVariables).toHaveBeenCalledWith(
@@ -902,13 +891,12 @@ describe('aztec node', () => {
       const checkpointNumber = CheckpointNumber(0);
       const proposedCheckpointBlockNumber = BlockNumber(0);
       const targetSlot = SlotNumber(1);
+      // No proposed checkpoint leads the frontier; the proposed-checkpoint frontier falls back to the
+      // checkpointed tip (block 0, slot 0), whose slot is read via getBlockData.
       l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({
-          proposed: proposedCheckpointBlockNumber,
-          proposedCheckpoint: checkpointNumber,
-          proposedCheckpointBlock: proposedCheckpointBlockNumber,
-        }),
+        makeTips({ proposed: proposedCheckpointBlockNumber, checkpointed: checkpointNumber }),
       );
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue(undefined);
       l2BlockSource.getBlockData.mockResolvedValue(
         makeSimulationBlockData(proposedCheckpointBlockNumber, SlotNumber(0), checkpointNumber),
       );
@@ -1405,9 +1393,8 @@ describe('aztec node', () => {
   /** Builds an L2Tips stub with the given checkpoint numbers per tip. */
   function makeTips(args: {
     proposed?: BlockNumber;
-    proposedCheckpointBlock?: BlockNumber;
-    proposedCheckpoint?: CheckpointNumber;
     checkpointed?: CheckpointNumber;
+    checkpointedBlock?: BlockNumber;
     proven?: CheckpointNumber;
     finalized?: CheckpointNumber;
   }): L2Tips {
@@ -1418,13 +1405,30 @@ describe('aztec node', () => {
     });
     return {
       proposed: makeBlockId(args.proposed),
-      checkpointed: makeTipId(args.checkpointed ?? CheckpointNumber(0)),
-      proposedCheckpoint: makeTipId(args.proposedCheckpoint ?? CheckpointNumber(0), args.proposedCheckpointBlock),
+      checkpointed: makeTipId(args.checkpointed ?? CheckpointNumber(0), args.checkpointedBlock),
       proven: makeTipId(args.proven ?? CheckpointNumber(0)),
       finalized: makeTipId(args.finalized ?? CheckpointNumber(0)),
     };
   }
 
+  /** Builds the payload of the atomic leading-proposed-checkpoint read (last block = startBlock). */
+  function makeProposedCheckpoint(args: {
+    checkpointNumber: CheckpointNumber;
+    blockNumber: BlockNumber;
+    slotNumber: SlotNumber;
+  }): ProposedCheckpointData {
+    return {
+      checkpointNumber: args.checkpointNumber,
+      header: CheckpointHeader.random({ slotNumber: args.slotNumber }),
+      archive: AppendOnlyTreeSnapshot.empty(),
+      checkpointOutHash: Fr.ZERO,
+      startBlock: args.blockNumber,
+      blockCount: 1,
+      totalManaUsed: 0n,
+      feeAssetPriceModifier: 0n,
+    };
+  }
+
   describe('getCheckpoint', () => {
     /** Builds a minimal ProposedCheckpointData stub. */
     function makeProposedCheckpointData(
@@ -1459,26 +1463,6 @@ describe('aztec node', () => {
     }
 
     describe('throw guards', () => {
-      it('throws BadRequestError when "proposed" resolves to a proposed entry and includeL1PublishInfo is requested', async () => {
-        l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposedCheckpoint: CheckpointNumber(5) }));
-        l2BlockSource.getCheckpointData.mockResolvedValue(undefined);
-        l2BlockSource.getProposedCheckpointData.mockResolvedValue(
-          makeProposedCheckpointData(CheckpointNumber(5), SlotNumber(10)),
-        );
-
-        await expect(node.getCheckpoint('proposed', { includeL1PublishInfo: true })).rejects.toThrow(BadRequestError);
-      });
-
-      it('throws BadRequestError when "proposed" resolves to a proposed entry and includeAttestations is requested', async () => {
-        l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposedCheckpoint: CheckpointNumber(5) }));
-        l2BlockSource.getCheckpointData.mockResolvedValue(undefined);
-        l2BlockSource.getProposedCheckpointData.mockResolvedValue(
-          makeProposedCheckpointData(CheckpointNumber(5), SlotNumber(10)),
-        );
-
-        await expect(node.getCheckpoint('proposed', { includeAttestations: true })).rejects.toThrow(BadRequestError);
-      });
-
       it('throws BadRequestError when number lookup resolves to a proposed entry and includeL1PublishInfo is requested', async () => {
         l2BlockSource.getCheckpointData.mockResolvedValue(undefined);
         l2BlockSource.getProposedCheckpointData.mockResolvedValue(
@@ -1503,30 +1487,6 @@ describe('aztec node', () => {
     });
 
     describe('fallback semantics', () => {
-      it('getCheckpoint("proposed") returns the projected proposed entry when one exists at the proposed-tip number', async () => {
-        l2BlockSource.getL2Tips.mockResolvedValue(makeTips({ proposedCheckpoint: CheckpointNumber(2) }));
-        l2BlockSource.getCheckpointData.mockResolvedValue(undefined);
-        const proposed = makeProposedCheckpointData(CheckpointNumber(2), SlotNumber(5));
-        l2BlockSource.getProposedCheckpointData.mockResolvedValue(proposed);
-
-        const result = await node.getCheckpoint('proposed');
-        expect(result).toBeDefined();
-        expect(result!.number).toEqual(CheckpointNumber(2));
-      });
-
-      it('getCheckpoint("proposed") returns the latest confirmed checkpoint when no proposed entry exists', async () => {
-        // When no proposed entry exists, the proposedCheckpoint tip falls back to the confirmed tip.
-        l2BlockSource.getL2Tips.mockResolvedValue(
-          makeTips({ proposedCheckpoint: CheckpointNumber(3), checkpointed: CheckpointNumber(3) }),
-        );
-        const confirmed = makeCheckpointData(CheckpointNumber(3));
-        l2BlockSource.getCheckpointData.mockResolvedValue(confirmed);
-
-        const result = await node.getCheckpoint('proposed');
-        expect(result).toBeDefined();
-        expect(result!.number).toEqual(CheckpointNumber(3));
-      });
-
       it('getCheckpoint({ number }) returns the confirmed entry when one exists', async () => {
         const confirmed = makeCheckpointData(CheckpointNumber(3));
         l2BlockSource.getCheckpointData.mockResolvedValue(confirmed);
@@ -1636,22 +1596,23 @@ describe('aztec node', () => {
   });
 
   describe('getCheckpointNumber', () => {
-    it('returns the proposed checkpoint number from proposedCheckpoint tip', async () => {
+    beforeEach(() => {
       l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({ proposedCheckpoint: CheckpointNumber(7), checkpointed: CheckpointNumber(5) }),
+        makeTips({ checkpointed: CheckpointNumber(5), proven: CheckpointNumber(3), finalized: CheckpointNumber(2) }),
       );
+    });
 
-      const result = await node.getCheckpointNumber('proposed');
-      expect(result).toEqual(CheckpointNumber(7));
+    it('returns the checkpointed number by default', async () => {
+      expect(await node.getCheckpointNumber()).toEqual(CheckpointNumber(5));
+      expect(await node.getCheckpointNumber('checkpointed')).toEqual(CheckpointNumber(5));
     });
 
-    it('returns the proposedCheckpoint tip number when it equals the confirmed checkpoint (fallback already baked in)', async () => {
-      l2BlockSource.getL2Tips.mockResolvedValue(
-        makeTips({ proposedCheckpoint: CheckpointNumber(5), checkpointed: CheckpointNumber(5) }),
-      );
+    it('returns the proven checkpoint number', async () => {
+      expect(await node.getCheckpointNumber('proven')).toEqual(CheckpointNumber(3));
+    });
 
-      const result = await node.getCheckpointNumber('proposed');
-      expect(result).toEqual(CheckpointNumber(5));
+    it('returns the finalized checkpoint number', async () => {
+      expect(await node.getCheckpointNumber('finalized')).toEqual(CheckpointNumber(2));
     });
   });
 
@@ -1691,7 +1652,6 @@ describe('aztec node', () => {
       return {
         proposed: blockId(args.proposed),
         checkpointed: tipId(args.checkpointed),
-        proposedCheckpoint: tipId(args.checkpointed),
         proven: tipId(args.proven),
         finalized: tipId(args.finalized),
       };
diff --git a/yarn-project/aztec-node/src/aztec-node/server.ts b/yarn-project/aztec-node/src/aztec-node/server.ts
index 21cdf1101744..ae752673bc0d 100644
--- a/yarn-project/aztec-node/src/aztec-node/server.ts
+++ b/yarn-project/aztec-node/src/aztec-node/server.ts
@@ -70,6 +70,7 @@ import {
   type CommitteeAttestation,
   type DataInBlock,
   type L2BlockSource,
+  type L2BlockTag,
   type L2Tips,
   type NormalizedBlockParameter,
   inspectBlockParameter,
@@ -98,11 +99,10 @@ import type {
   BlockIncludeOptions,
   BlockResponse,
   BlocksIncludeOptions,
-  ChainTip,
-  ChainTips,
   CheckpointIncludeOptions,
   CheckpointParameter,
   CheckpointResponse,
+  CheckpointTag,
   GetTxByHashOptions,
   PeerInfo,
   ProposalsForSlot,
@@ -250,9 +250,8 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     return status.syncSummary;
   }
 
-  public async getChainTips(): Promise<ChainTips> {
-    const { proposed, checkpointed, proven, finalized } = await this.blockSource.getL2Tips();
-    return { proposed, checkpointed, proven, finalized };
+  public getChainTips(): Promise<L2Tips> {
+    return this.blockSource.getL2Tips();
   }
 
   public getL1Constants() {
@@ -275,21 +274,19 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     return this.blockSource.getCheckpointsData(query);
   }
 
-  public async getBlockNumber(tip?: ChainTip): Promise<BlockNumber> {
+  public async getBlockNumber(tip?: L2BlockTag): Promise<BlockNumber> {
     if (tip === undefined || tip === 'proposed') {
       return this.blockSource.getBlockNumber();
     }
     return (await this.blockSource.getBlockNumber({ tag: tip })) ?? BlockNumber.ZERO;
   }
 
-  public async getCheckpointNumber(tip?: ChainTip): Promise<CheckpointNumber> {
+  public async getCheckpointNumber(tip?: CheckpointTag): Promise<CheckpointNumber> {
     const tips = await this.blockSource.getL2Tips();
     switch (tip) {
       case undefined:
       case 'checkpointed':
         return tips.checkpointed.checkpoint.number;
-      case 'proposed':
-        return tips.proposedCheckpoint.checkpoint.number;
       case 'proven':
         return tips.proven.checkpoint.number;
       case 'finalized':
@@ -297,8 +294,8 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     }
   }
 
-  private isChainTip(value: unknown): value is ChainTip {
-    return value === 'proposed' || value === 'checkpointed' || value === 'proven' || value === 'finalized';
+  private isCheckpointTag(value: unknown): value is CheckpointTag {
+    return value === 'checkpointed' || value === 'proven' || value === 'finalized';
   }
 
   /**
@@ -346,10 +343,10 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
   /**
    * Resolves a {@link CheckpointParameter} into a concrete `{ number }` or `{ slot }` query.
    *
-   * Tag-based parameters (`'proposed'`, `'checkpointed'`, `'proven'`, `'finalized'`) are
-   * translated up-front to the corresponding tip's checkpoint number via {@link L2BlockSource.getL2Tips}.
-   * After resolution the unified {@link getCheckpoint} flow can perform a single
-   * confirmed→proposed lookup against either store.
+   * Tag-based parameters (`'checkpointed'`, `'proven'`, `'finalized'`) are translated up-front to the
+   * corresponding tip's checkpoint number via {@link L2BlockSource.getL2Tips}. After resolution the
+   * unified {@link getCheckpoint} flow can perform a single confirmed→proposed lookup against either
+   * store.
    */
   private async resolveCheckpointParameter(
     param: CheckpointParameter,
@@ -357,11 +354,9 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     if (typeof param === 'number') {
       return { number: param as CheckpointNumber };
     }
-    if (this.isChainTip(param)) {
+    if (this.isCheckpointTag(param)) {
       const tips = await this.blockSource.getL2Tips();
       switch (param) {
-        case 'proposed':
-          return { number: tips.proposedCheckpoint.checkpoint.number };
         case 'checkpointed':
           return { number: tips.checkpointed.checkpoint.number };
         case 'proven':
@@ -1641,19 +1636,27 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     const coinbase = EthAddress.ZERO;
     const feeRecipient = AztecAddress.ZERO;
 
+    // Resolve the proposed-checkpoint frontier (latest proposed checkpoint, which leads the
+    // checkpointed tip, falling back to the checkpointed tip when none exists). The proposed payload
+    // carries its header slot, so no extra block fetch is needed to derive the slot.
+    const proposedCheckpoint = await this.blockSource.getProposedCheckpointData();
+    const proposedCheckpointBlockNumber = proposedCheckpoint
+      ? BlockNumber(proposedCheckpoint.startBlock + proposedCheckpoint.blockCount - 1)
+      : l2Tips.checkpointed.block.number;
+    const proposedCheckpointNumber = proposedCheckpoint?.checkpointNumber ?? l2Tips.checkpointed.checkpoint.number;
+
     // Define the slot for simulation as the max of the next L1 timestamp slot, the slot after the proposed
     // checkpoint, and the latest proposed block's slot.
-    const proposedCheckpointBlockData = await this.blockSource.getBlockData({
-      number: l2Tips.proposedCheckpoint.block.number,
-    });
-    const proposedCheckpointSlot = proposedCheckpointBlockData?.header.getSlot();
+    const proposedCheckpointSlot =
+      proposedCheckpoint?.header.slotNumber ??
+      (await this.blockSource.getBlockData({ number: proposedCheckpointBlockNumber }))?.header.getSlot();
     let slotAfterProposedCheckpoint: SlotNumber | undefined;
     if (proposedCheckpointSlot !== undefined) {
       slotAfterProposedCheckpoint = SlotNumber.fromBigInt(BigInt(proposedCheckpointSlot) + 1n);
     }
 
     let latestProposedBlockSlot: SlotNumber | undefined;
-    if (l2Tips.proposed.number > l2Tips.proposedCheckpoint.block.number) {
+    if (l2Tips.proposed.number > proposedCheckpointBlockNumber) {
       latestProposedBlockSlot = (
         await this.blockSource.getBlockData({ number: l2Tips.proposed.number })
       )?.header.getSlot();
@@ -1690,11 +1693,9 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     // the world state tree so simulation can take them into account. We detect if the next block would
     // start a new checkpoint by checking if the proposed checkpoint's block number matches the latest block number,
     // which means the next block would be the first block of the next checkpoint.
-    const targetCheckpoint = CheckpointNumber(
-      (l2Tips.proposedCheckpoint.checkpoint.number ?? CheckpointNumber.ZERO) + 1,
-    );
+    const targetCheckpoint = CheckpointNumber(proposedCheckpointNumber + 1);
     const nextCheckpointMessages: Fr[] | undefined =
-      l2Tips.proposedCheckpoint.block.number === l2Tips.proposed.number
+      proposedCheckpointBlockNumber === l2Tips.proposed.number
         ? await this.l1ToL2MessageSource.getL1ToL2Messages(targetCheckpoint).catch(err => {
             if (isErrorClass(err, L1ToL2MessagesNotReadyError)) {
               this.log.warn(
@@ -1716,7 +1717,7 @@ export class AztecNodeService implements AztecNode, AztecNodeAdmin, AztecNodeDeb
     if (nextCheckpointMessages !== undefined) {
       this.log.debug(
         `Appending ${nextCheckpointMessages.length} L1-to-L2 messages to the world state tree for the next checkpoint`,
-        { checkpointNumber: l2Tips.proposedCheckpoint.checkpoint.number + 1 },
+        { checkpointNumber: targetCheckpoint },
       );
       await appendL1ToL2MessagesToTree(merkleTreeFork, nextCheckpointMessages);
     }
diff --git a/yarn-project/end-to-end/src/e2e_epochs/epochs_missed_l1_publish.test.ts b/yarn-project/end-to-end/src/e2e_epochs/epochs_missed_l1_publish.test.ts
index fb5aa4afd1ce..d7cfa7be8bd6 100644
--- a/yarn-project/end-to-end/src/e2e_epochs/epochs_missed_l1_publish.test.ts
+++ b/yarn-project/end-to-end/src/e2e_epochs/epochs_missed_l1_publish.test.ts
@@ -12,8 +12,8 @@ import { retryUntil } from '@aztec/foundation/retry';
 import { bufferToHex } from '@aztec/foundation/string';
 import { timeoutPromise } from '@aztec/foundation/timer';
 import { type L2Block, L2BlockSourceEvents } from '@aztec/stdlib/block';
+import type { L2Tips } from '@aztec/stdlib/block';
 import { getTimestampForSlot } from '@aztec/stdlib/epoch-helpers';
-import type { ChainTips } from '@aztec/stdlib/interfaces/server';
 
 import { jest } from '@jest/globals';
 import { privateKeyToAccount } from 'viem/accounts';
@@ -178,7 +178,7 @@ describe('e2e_epochs/epochs_missed_l1_publish', () => {
     // We capture the L2 tips synchronously inside the handler — the archiver has already removed
     // the pruned blocks at emit time, so this snapshot reflects the rolled-back state before any
     // new pipelined block can be applied.
-    type PruneObservation = { slotNumber: SlotNumber; blocks: L2Block[]; tipsAtPrune: ChainTips };
+    type PruneObservation = { slotNumber: SlotNumber; blocks: L2Block[]; tipsAtPrune: L2Tips };
     const prunePromises: Promise<PruneObservation>[] = nodes.map(
       (node, idx) =>
         new Promise<PruneObservation>(resolve => {
diff --git a/yarn-project/end-to-end/src/e2e_epochs/epochs_orphan_block_prune.test.ts b/yarn-project/end-to-end/src/e2e_epochs/epochs_orphan_block_prune.test.ts
index dbf1a088b277..cca27d9b2b23 100644
--- a/yarn-project/end-to-end/src/e2e_epochs/epochs_orphan_block_prune.test.ts
+++ b/yarn-project/end-to-end/src/e2e_epochs/epochs_orphan_block_prune.test.ts
@@ -11,8 +11,8 @@ import { retryUntil } from '@aztec/foundation/retry';
 import { bufferToHex } from '@aztec/foundation/string';
 import { timeoutPromise } from '@aztec/foundation/timer';
 import { type L2Block, L2BlockSourceEvents } from '@aztec/stdlib/block';
+import type { L2Tips } from '@aztec/stdlib/block';
 import { getTimestampForSlot } from '@aztec/stdlib/epoch-helpers';
-import type { ChainTips } from '@aztec/stdlib/interfaces/server';
 
 import { jest } from '@jest/globals';
 import { privateKeyToAccount } from 'viem/accounts';
@@ -157,7 +157,7 @@ describe('e2e_epochs/epochs_orphan_block_prune', () => {
     // Subscribe to the prune event on every node before sequencers start, so we never miss it. We capture the chain
     // tips asynchronously inside the handler for log context, but do not assert on them — by the time the snapshot is
     // read, P2's rebuild may already have landed.
-    type PruneObservation = { slotNumber: SlotNumber; blocks: L2Block[]; tipsAtPrune: ChainTips };
+    type PruneObservation = { slotNumber: SlotNumber; blocks: L2Block[]; tipsAtPrune: L2Tips };
     const prunePromises: Promise<PruneObservation>[] = nodes.map(
       (node, idx) =>
         new Promise<PruneObservation>(resolve => {
diff --git a/yarn-project/end-to-end/src/e2e_l1_publisher/e2e_l1_publisher.test.ts b/yarn-project/end-to-end/src/e2e_l1_publisher/e2e_l1_publisher.test.ts
index 863e08e69bbc..b6a7da0e593c 100644
--- a/yarn-project/end-to-end/src/e2e_l1_publisher/e2e_l1_publisher.test.ts
+++ b/yarn-project/end-to-end/src/e2e_l1_publisher/e2e_l1_publisher.test.ts
@@ -319,7 +319,6 @@ describe('L1Publisher integration', () => {
           checkpointed: tipId,
           proven: tipId,
           finalized: tipId,
-          proposedCheckpoint: tipId,
         };
       },
       getBlockNumber(): Promise<BlockNumber> {
diff --git a/yarn-project/pxe/src/block_synchronizer/block_stream_source.ts b/yarn-project/pxe/src/block_synchronizer/block_stream_source.ts
index cbd6ed780cb2..8948ef621dae 100644
--- a/yarn-project/pxe/src/block_synchronizer/block_stream_source.ts
+++ b/yarn-project/pxe/src/block_synchronizer/block_stream_source.ts
@@ -11,10 +11,7 @@ export function blockStreamSourceFromAztecNode(
   node: AztecNode,
 ): Pick<L2BlockSource, 'getBlocks' | 'getBlockData' | 'getL2Tips'> {
   return {
-    getL2Tips: async () => {
-      const tips = await node.getChainTips();
-      return { ...tips, proposedCheckpoint: tips.checkpointed };
-    },
+    getL2Tips: () => node.getChainTips(),
 
     async getBlockData(query: BlockQuery): Promise<BlockData | undefined> {
       const response = await node.getBlock(query);
diff --git a/yarn-project/sequencer-client/src/sequencer/automine/automine_sequencer.ts b/yarn-project/sequencer-client/src/sequencer/automine/automine_sequencer.ts
index 243175965897..c50eeddc6562 100644
--- a/yarn-project/sequencer-client/src/sequencer/automine/automine_sequencer.ts
+++ b/yarn-project/sequencer-client/src/sequencer/automine/automine_sequencer.ts
@@ -409,7 +409,10 @@ export class AutomineSequencer {
       await this.deps.ethCheatCodes.setNextBlockTimestamp(slotBoundaryTs);
     }
 
-    const tips = await this.deps.l2BlockSource.getL2Tips();
+    const [tips, proposedCheckpoint] = await Promise.all([
+      this.deps.l2BlockSource.getL2Tips(),
+      this.deps.l2BlockSource.getProposedCheckpointData(),
+    ]);
     const syncedToBlockNumber = tips.proposed.number;
 
     // Ensure world state has processed the archiver's tip before forking. Without this,
@@ -419,7 +422,8 @@ export class AutomineSequencer {
     await this.deps.worldState.syncImmediate(BlockNumber(syncedToBlockNumber));
 
     const nextBlockNumber = BlockNumber(syncedToBlockNumber + 1);
-    const checkpointNumber = CheckpointNumber(tips.proposedCheckpoint.checkpoint.number + 1);
+    const parentCheckpointNumber = proposedCheckpoint?.checkpointNumber ?? tips.checkpointed.checkpoint.number;
+    const checkpointNumber = CheckpointNumber(parentCheckpointNumber + 1);
     const targetEpoch = getEpochAtSlot(SlotNumber(targetSlot), this.deps.l1Constants);
 
     this.log.verbose(`Building automine checkpoint`, {
diff --git a/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.test.ts b/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.test.ts
index f1da2c37dcee..89978ee6e45c 100644
--- a/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.test.ts
+++ b/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.test.ts
@@ -258,10 +258,6 @@ describe('CheckpointProposalJob', () => {
         block: { number: BlockNumber.ZERO, hash: 'block-hash' },
         checkpoint: { number: CheckpointNumber.ZERO, hash: 'checkpointed-ckpt-hash' },
       },
-      proposedCheckpoint: {
-        block: { number: BlockNumber.ZERO, hash: 'block-hash' },
-        checkpoint: { number: CheckpointNumber.ZERO, hash: 'proposed-ckpt-hash' },
-      },
       proven: {
         block: { number: BlockNumber.ZERO, hash: 'proven-hash' },
         checkpoint: { number: CheckpointNumber.ZERO, hash: 'proven-ckpt-hash' },
@@ -1093,10 +1089,6 @@ describe('CheckpointProposalJob', () => {
             hash: opts.checkpointedHash ?? parentCheckpointHash,
           },
         },
-        proposedCheckpoint: {
-          block: { number: BlockNumber(1), hash: 'block-hash' },
-          checkpoint: { number: CheckpointNumber(1), hash: parentCheckpointHash },
-        },
         proven: {
           block: { number: BlockNumber.ZERO, hash: 'proven-hash' },
           checkpoint: { number: CheckpointNumber.ZERO, hash: 'proven-ckpt-hash' },
diff --git a/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.timing.test.ts b/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.timing.test.ts
index 776929074d3c..2acf3e4cdf4c 100644
--- a/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.timing.test.ts
+++ b/yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.timing.test.ts
@@ -458,10 +458,6 @@ describe('CheckpointProposalJob Timing Tests', () => {
         block: { number: BlockNumber.ZERO, hash: '' },
         checkpoint: { number: CheckpointNumber(checkpointNumber - 1), hash: '' },
       },
-      proposedCheckpoint: {
-        block: { number: BlockNumber.ZERO, hash: '' },
-        checkpoint: { number: CheckpointNumber(checkpointNumber - 1), hash: '' },
-      },
       proven: {
         block: { number: BlockNumber.ZERO, hash: '' },
         checkpoint: { number: CheckpointNumber(0), hash: '' },
diff --git a/yarn-project/sequencer-client/src/sequencer/sequencer.test.ts b/yarn-project/sequencer-client/src/sequencer/sequencer.test.ts
index e60344fd8c61..2e6b5d04c067 100644
--- a/yarn-project/sequencer-client/src/sequencer/sequencer.test.ts
+++ b/yarn-project/sequencer-client/src/sequencer/sequencer.test.ts
@@ -314,10 +314,6 @@ describe('sequencer', () => {
       getBlockNumber: mockFn().mockResolvedValue(lastBlockNumber),
       getL2Tips: mockFn().mockResolvedValue({
         proposed: { number: lastBlockNumber, hash },
-        proposedCheckpoint: {
-          block: { number: lastBlockNumber, hash },
-          checkpoint: { number: CheckpointNumber.ZERO, hash: GENESIS_CHECKPOINT_HEADER_HASH.toString() },
-        },
         checkpointed: {
           block: { number: lastBlockNumber, hash },
           checkpoint: { number: CheckpointNumber.ZERO, hash: GENESIS_CHECKPOINT_HEADER_HASH.toString() },
@@ -343,10 +339,6 @@ describe('sequencer', () => {
       getL1ToL2Messages: () => Promise.resolve(Array(NUMBER_OF_L1_L2_MESSAGES_PER_ROLLUP).fill(Fr.ZERO)),
       getL2Tips: mockFn().mockResolvedValue({
         proposed: { number: lastBlockNumber, hash },
-        proposedCheckpoint: {
-          block: { number: lastBlockNumber, hash },
-          checkpoint: { number: CheckpointNumber.ZERO, hash: GENESIS_CHECKPOINT_HEADER_HASH.toString() },
-        },
         checkpointed: {
           block: { number: lastBlockNumber, hash },
           checkpoint: { number: CheckpointNumber.ZERO, hash: GENESIS_CHECKPOINT_HEADER_HASH.toString() },
@@ -1273,9 +1265,8 @@ describe('sequencer', () => {
       await setupSingleTxBlock();
 
       // Override to non-genesis state so checkSync doesn't take the genesis path.
-      // proposedCheckpoint is set with checkpoint number 1 > checkpointed tip 0, so hasProposedCheckpoint is true.
+      // The proposed checkpoint has number 1 > checkpointed tip 0, so hasProposedCheckpoint is true.
       const nonGenesisHash = Fr.random().toString();
-      const proposedCheckpointHash = Fr.random().toString();
       worldState.status.mockResolvedValue({
         state: WorldStateRunningState.IDLE,
         syncSummary: {
@@ -1288,10 +1279,6 @@ describe('sequencer', () => {
       } satisfies WorldStateSynchronizerStatus);
       const tipsWithBlock1 = {
         proposed: { number: BlockNumber(1), hash: nonGenesisHash },
-        proposedCheckpoint: {
-          block: { number: BlockNumber(1), hash: nonGenesisHash },
-          checkpoint: { number: CheckpointNumber(1), hash: proposedCheckpointHash },
-        },
         checkpointed: {
           block: { number: BlockNumber(1), hash: nonGenesisHash },
           checkpoint: { number: CheckpointNumber.ZERO, hash: GENESIS_CHECKPOINT_HEADER_HASH.toString() },
@@ -1326,7 +1313,7 @@ describe('sequencer', () => {
         blockCount: 1,
         totalManaUsed: 0n,
         feeAssetPriceModifier: 0n,
-      } satisfies ProposedCheckpointData);
+      });
 
       await sequencer.work();
 
@@ -1342,7 +1329,6 @@ describe('sequencer', () => {
       // Confirmed checkpoint is 1, pending is 2, proposed tip is in checkpoint 3.
       // So sequencer would try to build checkpoint 4, which exceeds the 1-deep pipeline limit.
       const nonGenesisHash = Fr.random().toString();
-      const proposedCheckpointHash = Fr.random().toString();
       const checkpointedHash = Fr.random().toString();
       worldState.status.mockResolvedValue({
         state: WorldStateRunningState.IDLE,
@@ -1356,10 +1342,6 @@ describe('sequencer', () => {
       } satisfies WorldStateSynchronizerStatus);
       const tips = {
         proposed: { number: BlockNumber(3), hash: nonGenesisHash },
-        proposedCheckpoint: {
-          block: { number: BlockNumber(2), hash: nonGenesisHash },
-          checkpoint: { number: CheckpointNumber(2), hash: proposedCheckpointHash },
-        },
         checkpointed: {
           block: { number: BlockNumber(1), hash: nonGenesisHash },
           checkpoint: { number: CheckpointNumber(1), hash: checkpointedHash },
@@ -1385,9 +1367,7 @@ describe('sequencer', () => {
         checkpointNumber: CheckpointNumber(3),
         indexWithinCheckpoint: IndexWithinCheckpoint(0),
       } satisfies BlockData);
-      l2BlockSource.getProposedCheckpointData.mockResolvedValue({
-        checkpointNumber: CheckpointNumber(2),
-      } as any);
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue({ checkpointNumber: CheckpointNumber(2) } as any);
 
       await sequencer.work();
 
@@ -1412,7 +1392,6 @@ describe('sequencer', () => {
 
       // Set up a pipelined parent (pending override = parentCheckpointNumber = 1).
       const nonGenesisHash = Fr.random().toString();
-      const proposedCheckpointHash = Fr.random().toString();
       worldState.status.mockResolvedValue({
         state: WorldStateRunningState.IDLE,
         syncSummary: {
@@ -1425,10 +1404,6 @@ describe('sequencer', () => {
       } satisfies WorldStateSynchronizerStatus);
       const tipsWithBlock1 = {
         proposed: { number: BlockNumber(1), hash: nonGenesisHash },
-        proposedCheckpoint: {
-          block: { number: BlockNumber(1), hash: nonGenesisHash },
-          checkpoint: { number: CheckpointNumber(1), hash: proposedCheckpointHash },
-        },
         checkpointed: {
           block: { number: BlockNumber(1), hash: nonGenesisHash },
           checkpoint: { number: CheckpointNumber.ZERO, hash: GENESIS_CHECKPOINT_HEADER_HASH.toString() },
@@ -1463,7 +1438,7 @@ describe('sequencer', () => {
         blockCount: 1,
         totalManaUsed: 0n,
         feeAssetPriceModifier: 0n,
-      } satisfies ProposedCheckpointData);
+      });
 
       await sequencer.work();
 
@@ -1498,18 +1473,17 @@ describe('sequencer', () => {
   describe('checkSync orphan-block guard', () => {
     // Mocks all sync sources so checkSync passes its earlier equality checks and reaches the orphan
     // guard, with the world-state tip at `blockNumber` (in `blockCheckpointNumber`) while the
-    // checkpointed and proposed-checkpoint tips sit at the given checkpoint numbers.
+    // checkpointed tip sits at `checkpointedCheckpointNumber`. The leading proposed checkpoint (if any)
+    // is supplied via `getProposedCheckpointData`.
     const setupSyncedToBlock = (opts: {
       blockNumber: BlockNumber;
       blockSlot: SlotNumber;
       blockCheckpointNumber: CheckpointNumber;
       checkpointedCheckpointNumber: CheckpointNumber;
-      proposedCheckpointTipNumber: CheckpointNumber;
-      proposedCheckpointData: ProposedCheckpointData | undefined;
+      proposedCheckpoint: ProposedCheckpointData | undefined;
     }) => {
       const hash = Fr.random().toString();
       const checkpointHash = Fr.random().toString();
-      const proposedCheckpointHash = Fr.random().toString();
       worldState.status.mockResolvedValue({
         state: WorldStateRunningState.IDLE,
         syncSummary: {
@@ -1522,10 +1496,6 @@ describe('sequencer', () => {
       } satisfies WorldStateSynchronizerStatus);
       const tips = {
         proposed: { number: opts.blockNumber, hash },
-        proposedCheckpoint: {
-          block: { number: opts.blockNumber, hash },
-          checkpoint: { number: opts.proposedCheckpointTipNumber, hash: proposedCheckpointHash },
-        },
         checkpointed: {
           block: { number: opts.blockNumber, hash },
           checkpoint: { number: opts.checkpointedCheckpointNumber, hash: checkpointHash },
@@ -1551,20 +1521,19 @@ describe('sequencer', () => {
         checkpointNumber: opts.blockCheckpointNumber,
         indexWithinCheckpoint: IndexWithinCheckpoint(0),
       } satisfies BlockData);
-      l2BlockSource.getProposedCheckpointData.mockResolvedValue(opts.proposedCheckpointData);
+      l2BlockSource.getProposedCheckpointData.mockResolvedValue(opts.proposedCheckpoint);
     };
 
     it('returns undefined and logs debug while waiting for a matching proposed checkpoint', async () => {
-      // Local tip is a block at checkpoint 3, but the checkpointed and proposed-checkpoint tips are
-      // still at checkpoint 2 and no proposed checkpoint 3 exists: an orphan block-only tip whose
-      // enclosing checkpoint has not materialized into the archiver.
+      // Local tip is a block at checkpoint 3, but the checkpointed tip is still at checkpoint 2 and no
+      // proposed checkpoint 3 exists: an orphan block-only tip whose enclosing checkpoint has not
+      // materialized into the archiver.
       setupSyncedToBlock({
         blockNumber: BlockNumber(3),
         blockSlot: SlotNumber(3),
         blockCheckpointNumber: CheckpointNumber(3),
         checkpointedCheckpointNumber: CheckpointNumber(2),
-        proposedCheckpointTipNumber: CheckpointNumber(2),
-        proposedCheckpointData: undefined,
+        proposedCheckpoint: undefined,
       });
       const warnSpy = jest.spyOn(sequencer.getLogger(), 'warn');
       const debugSpy = jest.spyOn(sequencer.getLogger(), 'debug');
@@ -1578,8 +1547,7 @@ describe('sequencer', () => {
         expect.objectContaining({
           blockCheckpointNumber: CheckpointNumber(3),
           checkpointedCheckpointNumber: CheckpointNumber(2),
-          proposedCheckpointTipNumber: CheckpointNumber(2),
-          proposedCheckpointDataNumber: undefined,
+          proposedCheckpointTipNumber: undefined,
         }),
       );
     });
@@ -1590,8 +1558,7 @@ describe('sequencer', () => {
         blockSlot: SlotNumber(3),
         blockCheckpointNumber: CheckpointNumber(3),
         checkpointedCheckpointNumber: CheckpointNumber(2),
-        proposedCheckpointTipNumber: CheckpointNumber(3),
-        proposedCheckpointData: {
+        proposedCheckpoint: {
           checkpointNumber: CheckpointNumber(3),
           header: CheckpointHeader.empty(),
           archive: AppendOnlyTreeSnapshot.empty(),
@@ -1600,7 +1567,7 @@ describe('sequencer', () => {
           blockCount: 1,
           totalManaUsed: 0n,
           feeAssetPriceModifier: 0n,
-        } satisfies ProposedCheckpointData,
+        },
       });
 
       const result = await sequencer.checkSyncForTest({ ts: 1000n, slot: SlotNumber(2) });
diff --git a/yarn-project/sequencer-client/src/sequencer/sequencer.ts b/yarn-project/sequencer-client/src/sequencer/sequencer.ts
index cd2e66d6f4f2..ba58e27a2893 100644
--- a/yarn-project/sequencer-client/src/sequencer/sequencer.ts
+++ b/yarn-project/sequencer-client/src/sequencer/sequencer.ts
@@ -805,9 +805,7 @@ export class Sequencer extends (EventEmitter as new () => TypedEventEmitter<Sequ
         number: syncSummary.latestBlockNumber,
         hash: syncSummary.latestBlockHash,
       })),
-      this.l2BlockSource
-        .getL2Tips()
-        .then(t => ({ proposed: t.proposed, checkpointed: t.checkpointed, proposedCheckpoint: t.proposedCheckpoint })),
+      this.l2BlockSource.getL2Tips().then(t => ({ proposed: t.proposed, checkpointed: t.checkpointed })),
       this.p2pClient.getStatus().then(p2p => p2p.syncedToL2Block),
       this.l1ToL2MessageSource.getL2Tips().then(t => ({ proposed: t.proposed, checkpointed: t.checkpointed })),
       this.l2BlockSource.getPendingChainValidationStatus(),
@@ -852,16 +850,17 @@ export class Sequencer extends (EventEmitter as new () => TypedEventEmitter<Sequ
     // matching proposed checkpoint (e.g. it crashed before assembling it). Building on this orphan block
     // would fork the chain off a tip no other node can follow. The archiver prunes these orphan blocks
     // once their build slot ends; this guard is the correctness barrier during the grace window before.
+    // `getProposedCheckpointData()` returns the latest proposed checkpoint payload, which is always
+    // the leading one (a proposed entry is only stored beyond the confirmed frontier and is deleted
+    // on confirmation). It carries no tip, so there is no tip-vs-payload split read to reconcile.
     if (
       blockData.checkpointNumber > l2Tips.checkpointed.checkpoint.number &&
-      (l2Tips.proposedCheckpoint.checkpoint.number !== blockData.checkpointNumber ||
-        proposedCheckpointData?.checkpointNumber !== blockData.checkpointNumber)
+      proposedCheckpointData?.checkpointNumber !== blockData.checkpointNumber
     ) {
       const logCtx = {
         blockCheckpointNumber: blockData.checkpointNumber,
         checkpointedCheckpointNumber: l2Tips.checkpointed.checkpoint.number,
-        proposedCheckpointTipNumber: l2Tips.proposedCheckpoint.checkpoint.number,
-        proposedCheckpointDataNumber: proposedCheckpointData?.checkpointNumber,
+        proposedCheckpointTipNumber: proposedCheckpointData?.checkpointNumber,
         blockNumber: blockData.header.getBlockNumber(),
         blockSlot: blockData.header.getSlot(),
         syncedL2Slot,
@@ -872,27 +871,7 @@ export class Sequencer extends (EventEmitter as new () => TypedEventEmitter<Sequ
       return undefined;
     }
 
-    const hasProposedCheckpoint = l2Tips.proposedCheckpoint.checkpoint.number > l2Tips.checkpointed.checkpoint.number;
-
-    // The l2Tips and proposedCheckpointData reads above come from independent archiver snapshots
-    // (a JS-side tips cache vs. a direct store read on `#proposedCheckpoints`). A concurrent archiver
-    // write that mutates both can be observed split, leaving us with `hasProposedCheckpoint=true` but
-    // no proposedCheckpointData (or one whose number doesn't match the tip). Refuse to proceed in that
-    // window — the next checkSync tick will see a coherent snapshot.
-    if (
-      hasProposedCheckpoint &&
-      (!proposedCheckpointData ||
-        proposedCheckpointData.checkpointNumber !== l2Tips.proposedCheckpoint.checkpoint.number)
-    ) {
-      this.log.warn(`Sequencer sync check failed: inconsistent proposed-checkpoint state`, {
-        proposedCheckpointTipNumber: l2Tips.proposedCheckpoint.checkpoint.number,
-        checkpointedTipNumber: l2Tips.checkpointed.checkpoint.number,
-        proposedCheckpointDataNumber: proposedCheckpointData?.checkpointNumber,
-        syncedL2Slot,
-        ...args,
-      });
-      return undefined;
-    }
+    const hasProposedCheckpoint = proposedCheckpointData !== undefined;
 
     // Check that the proposed checkpoint is indeed the parent of the checkpoint we'll be building
     // The checkpoint number to build is derived as blockData.checkpointNumber + 1
diff --git a/yarn-project/stdlib/src/block/l2_block_source.ts b/yarn-project/stdlib/src/block/l2_block_source.ts
index fe3a6175cef4..34089220669c 100644
--- a/yarn-project/stdlib/src/block/l2_block_source.ts
+++ b/yarn-project/stdlib/src/block/l2_block_source.ts
@@ -241,7 +241,10 @@ export interface L2BlockSource {
 
   /**
    * Looks up a proposed (archiver-internal, not-yet-L1-confirmed) checkpoint.
-   * Returns the latest proposed entry when called with no args or `{ tag: 'proposed' }`.
+   * Returns the latest proposed entry when called with no args or `{ tag: 'proposed' }`; since a
+   * proposed entry can only be stored with a checkpoint number beyond the confirmed frontier (and is
+   * deleted on confirmation), the latest entry is always the leading one. Callers derive the proposed
+   * tip from the payload (checkpoint number, and last block `startBlock + blockCount - 1`).
    * With `{ number }` or `{ slot }`, returns the matching entry or undefined.
    * Never falls back to confirmed checkpoints.
    */
@@ -327,36 +330,29 @@ export interface L2BlockSourceEventEmitter extends L2BlockSource {
 }
 
 /**
- * Identifier for L2 block tags. Internal counterpart to {@link BlockTag} that exposes
- * the additional `proposedCheckpoint` value (used for the optimistic chain tip on the
- * archiver side) and omits `latest` (which is an alias for `proposed` accepted only at
- * the public RPC surface).
+ * Identifier for L2 block tags. Internal counterpart to {@link BlockTag} that omits `latest`
+ * (which is an alias for `proposed` accepted only at the public RPC surface).
  *
  * - proposed: Latest block proposed on L2.
- * - proposedCheckpoint: Latest block in the most recent proposed checkpoint (archiver-internal).
  * - checkpointed: Latest block whose enclosing checkpoint has been published on L1.
  * - proven: Latest block whose enclosing checkpoint has been proven on L1.
  * - finalized: Latest block whose proving L1 transaction has reached L1 finality.
- *
- * TODO(palla): Remove `proposedCheckpoint` and unify with `proposed`.
  */
-export type L2BlockTag = 'proposed' | 'proposedCheckpoint' | 'checkpointed' | 'proven' | 'finalized';
+export type L2BlockTag = 'proposed' | 'checkpointed' | 'proven' | 'finalized';
 
 /** Tips of the L2 chain. */
 export type L2Tips = {
   proposed: L2BlockId;
   checkpointed: L2TipId;
-  proposedCheckpoint: L2TipId;
   proven: L2TipId;
   finalized: L2TipId;
 };
 
 /**
- * Tips of the L2 chain as tracked by a local provider (world-state, l2-tips-store). Omits
- * `proposedCheckpoint`, which is degenerate in local stores (always equal to `checkpointed`) and
- * is only meaningful on the archiver side via {@link L2BlockSource}.
+ * Tips of the L2 chain as tracked by a local provider (world-state, l2-tips-store). Identical to
+ * {@link L2Tips}; the alias is retained for call sites that document a local-only provenance.
  */
-export type LocalL2Tips = Omit<L2Tips, 'proposedCheckpoint'>;
+export type LocalL2Tips = L2Tips;
 
 export const GENESIS_CHECKPOINT_HEADER_HASH = CheckpointHeader.empty().hash();
 
@@ -398,7 +394,6 @@ const L2TipIdSchema = z.object({
 export const L2TipsSchema = z.object({
   proposed: L2BlockIdSchema,
   checkpointed: L2TipIdSchema,
-  proposedCheckpoint: L2TipIdSchema,
   proven: L2TipIdSchema,
   finalized: L2TipIdSchema,
 });
diff --git a/yarn-project/stdlib/src/block/l2_block_stream/l2_block_stream.test.ts b/yarn-project/stdlib/src/block/l2_block_stream/l2_block_stream.test.ts
index a123e9160682..28f7cb9d76cf 100644
--- a/yarn-project/stdlib/src/block/l2_block_stream/l2_block_stream.test.ts
+++ b/yarn-project/stdlib/src/block/l2_block_stream/l2_block_stream.test.ts
@@ -61,14 +61,7 @@ describe('L2BlockStream', () => {
   });
 
   /** Sets the remote tips. All tips default to 0 except latest. */
-  const setRemoteTips = (
-    latest_: number,
-    checkpointed_?: number,
-    proven?: number,
-    finalized?: number,
-    proposedCheckpoint_?: number,
-  ) => {
-    proposedCheckpoint_ = proposedCheckpoint_ ?? 0;
+  const setRemoteTips = (latest_: number, checkpointed_?: number, proven?: number, finalized?: number) => {
     checkpointed_ = checkpointed_ ?? 0;
     proven = proven ?? 0;
     finalized = finalized ?? 0;
@@ -77,7 +70,6 @@ describe('L2BlockStream', () => {
     blockSource.getL2Tips.mockResolvedValue({
       proposed: { number: BlockNumber(latest), hash: makeHash(latest) },
       checkpointed: makeTipId(checkpointed_),
-      proposedCheckpoint: makeTipId(proposedCheckpoint_),
       proven: makeTipId(proven),
       finalized: makeTipId(finalized),
     });
diff --git a/yarn-project/stdlib/src/interfaces/archiver.test.ts b/yarn-project/stdlib/src/interfaces/archiver.test.ts
index db0f41c3468d..c1e2631cfad6 100644
--- a/yarn-project/stdlib/src/interfaces/archiver.test.ts
+++ b/yarn-project/stdlib/src/interfaces/archiver.test.ts
@@ -153,7 +153,6 @@ describe('ArchiverApiSchema', () => {
     expect(result).toEqual({
       proposed: { number: 1, hash: `0x01` },
       checkpointed: expectedTipId,
-      proposedCheckpoint: expectedTipId,
       proven: expectedTipId,
       finalized: expectedTipId,
     });
@@ -477,7 +476,6 @@ class MockArchiver implements ArchiverApi {
     return Promise.resolve({
       proposed: { number: BlockNumber(1), hash: `0x01` },
       checkpointed: tipId,
-      proposedCheckpoint: tipId,
       proven: tipId,
       finalized: tipId,
     });
diff --git a/yarn-project/stdlib/src/interfaces/aztec-node.test.ts b/yarn-project/stdlib/src/interfaces/aztec-node.test.ts
index bd404091f483..fb23d9d56458 100644
--- a/yarn-project/stdlib/src/interfaces/aztec-node.test.ts
+++ b/yarn-project/stdlib/src/interfaces/aztec-node.test.ts
@@ -22,7 +22,7 @@ import { AztecAddress } from '../aztec-address/index.js';
 import type { BlockData } from '../block/block_data.js';
 import type { DataInBlock } from '../block/in_block.js';
 import { BlockHash, type BlockParameter } from '../block/index.js';
-import type { CheckpointsQuery } from '../block/l2_block_source.js';
+import type { CheckpointsQuery, L2BlockTag, L2Tips } from '../block/l2_block_source.js';
 import type { CheckpointData } from '../checkpoint/checkpoint_data.js';
 import {
   type ContractClassPublic,
@@ -64,7 +64,7 @@ import type { AllowedElement } from './allowed_element.js';
 import { MAX_RPC_LEN } from './api_limit.js';
 import { type AztecNode, AztecNodeApiSchema, type GetTxByHashOptions } from './aztec-node.js';
 import type { BlockIncludeOptions, BlockResponse, BlocksIncludeOptions } from './block_response.js';
-import type { ChainTip, ChainTips } from './chain_tips.js';
+import type { CheckpointTag } from './chain_tips.js';
 import type { CheckpointParameter } from './checkpoint_parameter.js';
 import type { CheckpointIncludeOptions, CheckpointResponse } from './checkpoint_response.js';
 import type { SequencerConfig } from './configs.js';
@@ -596,7 +596,7 @@ class MockAztecNode implements AztecNode {
     });
   }
 
-  getChainTips(): Promise<ChainTips> {
+  getChainTips(): Promise<L2Tips> {
     const tipId = {
       block: { number: BlockNumber(1), hash: `0x01` },
       checkpoint: { number: CheckpointNumber(1), hash: `0x01` },
@@ -765,10 +765,10 @@ class MockAztecNode implements AztecNode {
   getMaxPriorityFees(): Promise<GasFees> {
     return Promise.resolve(GasFees.empty());
   }
-  getBlockNumber(_tip?: ChainTip): Promise<BlockNumber> {
+  getBlockNumber(_tip?: L2BlockTag): Promise<BlockNumber> {
     return Promise.resolve(BlockNumber(1));
   }
-  getCheckpointNumber(_tip?: ChainTip): Promise<CheckpointNumber> {
+  getCheckpointNumber(_tip?: CheckpointTag): Promise<CheckpointNumber> {
     return Promise.resolve(CheckpointNumber(1));
   }
   isReady(): Promise<boolean> {
diff --git a/yarn-project/stdlib/src/interfaces/aztec-node.ts b/yarn-project/stdlib/src/interfaces/aztec-node.ts
index 99ee4d88a88c..62baf29ecb06 100644
--- a/yarn-project/stdlib/src/interfaces/aztec-node.ts
+++ b/yarn-project/stdlib/src/interfaces/aztec-node.ts
@@ -23,9 +23,15 @@ import { z } from 'zod';
 import type { AztecAddress } from '../aztec-address/index.js';
 import { type BlockData, BlockDataSchema } from '../block/block_data.js';
 import { BlockHash } from '../block/block_hash.js';
-import { type BlockParameter, BlockParameterSchema } from '../block/block_parameter.js';
+import { type BlockParameter, BlockParameterSchema, BlockTagWithoutLatestSchema } from '../block/block_parameter.js';
 import { type DataInBlock, dataInBlockSchemaFor } from '../block/in_block.js';
-import { type CheckpointsQuery, CheckpointsQuerySchema } from '../block/l2_block_source.js';
+import {
+  type CheckpointsQuery,
+  CheckpointsQuerySchema,
+  type L2BlockTag,
+  type L2Tips,
+  L2TipsSchema,
+} from '../block/l2_block_source.js';
 import { type CheckpointData, CheckpointDataSchema } from '../checkpoint/checkpoint_data.js';
 import {
   type ContractClassPublic,
@@ -80,7 +86,7 @@ import {
   type BlocksIncludeOptions,
   BlocksIncludeOptionsSchema,
 } from './block_response.js';
-import { type ChainTip, ChainTipSchema, type ChainTips, ChainTipsSchema } from './chain_tips.js';
+import { type CheckpointTag, CheckpointTagSchema } from './chain_tips.js';
 import { type CheckpointParameter, CheckpointParameterSchema } from './checkpoint_parameter.js';
 import {
   type CheckpointIncludeOptions,
@@ -232,23 +238,20 @@ export interface AztecNode {
   ): Promise<L2ToL1MembershipWitness | undefined>;
 
   /**
-   * Returns the block number at a given chain tip, or the latest proposed block number when
+   * Returns the block number at a given block tag, or the latest proposed block number when
    * `tip` is omitted.
    */
-  getBlockNumber(tip?: ChainTip): Promise<BlockNumber>;
+  getBlockNumber(tip?: L2BlockTag): Promise<BlockNumber>;
 
   /**
-   * Returns the checkpoint number at a given chain tip, or the latest checkpoint number when
-   * `tip` is omitted.
-   *
-   * @remarks **Semantic foot-gun**: block-side `'proposed'` means "latest proposed block" (chain
-   * head), but checkpoint-side `'proposed'` means "latest confirmed checkpoint" — pre-L1-confirm
-   * checkpoints are not exposed over RPC. `'checkpointed'` on the checkpoint side is equivalent.
+   * Returns the checkpoint number at a given checkpoint tag, or the latest checkpointed number when
+   * `tip` is omitted. The proposed-but-unconfirmed checkpoint frontier is archiver-internal and not
+   * exposed over RPC, so `'proposed'` is not a valid checkpoint tag (see {@link CheckpointTag}).
    */
-  getCheckpointNumber(tip?: ChainTip): Promise<CheckpointNumber>;
+  getCheckpointNumber(tip?: CheckpointTag): Promise<CheckpointNumber>;
 
   /** Returns the tips of the L2 chain. */
-  getChainTips(): Promise<ChainTips>;
+  getChainTips(): Promise<L2Tips>;
 
   /** Returns the rollup constants for the current chain. */
   getL1Constants(): Promise<L1RollupConstants>;
@@ -622,11 +625,11 @@ export const AztecNodeApiSchema: ApiSchemaFor<AztecNode> = {
     output: L2ToL1MembershipWitnessSchema.optional(),
   }),
 
-  getBlockNumber: z.function({ input: z.tuple([optional(ChainTipSchema)]), output: BlockNumberSchema }),
+  getBlockNumber: z.function({ input: z.tuple([optional(BlockTagWithoutLatestSchema)]), output: BlockNumberSchema }),
 
-  getCheckpointNumber: z.function({ input: z.tuple([optional(ChainTipSchema)]), output: CheckpointNumberSchema }),
+  getCheckpointNumber: z.function({ input: z.tuple([optional(CheckpointTagSchema)]), output: CheckpointNumberSchema }),
 
-  getChainTips: z.function({ input: z.tuple([]), output: ChainTipsSchema }),
+  getChainTips: z.function({ input: z.tuple([]), output: L2TipsSchema }),
 
   getL1Constants: z.function({ input: z.tuple([]), output: L1RollupConstantsSchema }),
 
diff --git a/yarn-project/stdlib/src/interfaces/chain_tips.ts b/yarn-project/stdlib/src/interfaces/chain_tips.ts
index fde42b09a136..45ccb6f313c7 100644
--- a/yarn-project/stdlib/src/interfaces/chain_tips.ts
+++ b/yarn-project/stdlib/src/interfaces/chain_tips.ts
@@ -1,24 +1,16 @@
 import { z } from 'zod';
 
-import { type L2BlockTag, type L2Tips, L2TipsSchema } from '../block/l2_block_source.js';
-
 /**
- * Public chain-tip selectors usable in RPC requests.
- * Omits internal-only tags (e.g. `proposedCheckpoint`) from {@link L2BlockTag}.
+ * Public checkpoint-tip selectors usable in RPC requests.
+ *
+ * `'proposed'` is intentionally excluded: the proposed-but-unconfirmed checkpoint frontier is an
+ * archiver-internal pipelining concept, not part of the public chain-tip surface. Select the
+ * proposed *block* tip with a block tag (`L2BlockTag`) instead.
  */
-export type ChainTip = Exclude<L2BlockTag, 'proposedCheckpoint'>;
+export type CheckpointTag = 'checkpointed' | 'proven' | 'finalized';
 
-export const ChainTipSchema = z.union([
-  z.literal('proposed'),
+export const CheckpointTagSchema = z.union([
   z.literal('checkpointed'),
   z.literal('proven'),
   z.literal('finalized'),
-]) satisfies z.ZodType<ChainTip>;
-
-/**
- * Tips of the L2 chain.
- * Omits the sequencer-internal `proposedCheckpoint` from the public RPC surface.
- */
-export type ChainTips = Omit<L2Tips, 'proposedCheckpoint'>;
-
-export const ChainTipsSchema = L2TipsSchema.omit({ proposedCheckpoint: true });
+]) satisfies z.ZodType<CheckpointTag>;
diff --git a/yarn-project/stdlib/src/interfaces/checkpoint_parameter.ts b/yarn-project/stdlib/src/interfaces/checkpoint_parameter.ts
index 0c50a436d753..c7bd38738818 100644
--- a/yarn-project/stdlib/src/interfaces/checkpoint_parameter.ts
+++ b/yarn-project/stdlib/src/interfaces/checkpoint_parameter.ts
@@ -2,18 +2,18 @@ import { CheckpointNumberSchema, SlotNumberSchema } from '@aztec/foundation/bran
 
 import { z } from 'zod';
 
-import { ChainTipSchema } from './chain_tips.js';
+import { CheckpointTagSchema } from './chain_tips.js';
 
 /**
  * Selector for a checkpoint in RPC calls.
  *
  * Accepts a numeric checkpoint number (or `{ number }`), a slot number (`{ slot }`),
- * or a chain-tip name (e.g. `'proposed'`, `'proven'`).
+ * or a checkpoint-tip name (e.g. `'checkpointed'`, `'proven'`, `'finalized'`).
  */
 export const CheckpointParameterSchema = z.union([
   z.object({ number: CheckpointNumberSchema }).strict(),
   z.object({ slot: SlotNumberSchema }).strict(),
-  ChainTipSchema,
+  CheckpointTagSchema,
   CheckpointNumberSchema,
 ]);
 
diff --git a/yarn-project/stdlib/src/interfaces/prover-node.test.ts b/yarn-project/stdlib/src/interfaces/prover-node.test.ts
index 770412e760f9..a6a832ed72a5 100644
--- a/yarn-project/stdlib/src/interfaces/prover-node.test.ts
+++ b/yarn-project/stdlib/src/interfaces/prover-node.test.ts
@@ -45,7 +45,6 @@ describe('ProvingNodeApiSchema', () => {
     expect(result).toEqual({
       proposed: { number: 1, hash: `0x01` },
       checkpointed: expectedTipId,
-      proposedCheckpoint: expectedTipId,
       proven: expectedTipId,
       finalized: expectedTipId,
     });
@@ -76,7 +75,6 @@ class MockProverNode implements ProverNodeApi {
     return Promise.resolve({
       proposed: { number: BlockNumber(1), hash: `0x01` },
       checkpointed: tipId,
-      proposedCheckpoint: tipId,
       proven: tipId,
       finalized: tipId,
     });
diff --git a/yarn-project/stdlib/src/tests/factories.ts b/yarn-project/stdlib/src/tests/factories.ts
index 0198fabd4bb4..298efb24082a 100644
--- a/yarn-project/stdlib/src/tests/factories.ts
+++ b/yarn-project/stdlib/src/tests/factories.ts
@@ -1745,10 +1745,6 @@ export function makeL2Tips(
       block: { number: bn, hash },
       checkpoint: { number: cpn, hash: cph },
     },
-    proposedCheckpoint: {
-      block: { number: bn, hash },
-      checkpoint: { number: cpn, hash: cph },
-    },
     proven: {
       block: { number: bn, hash },
       checkpoint: { number: cpn, hash: cph },
diff --git a/yarn-project/txe/src/state_machine/archiver.ts b/yarn-project/txe/src/state_machine/archiver.ts
index ab3b92562876..c91789f7d3bf 100644
--- a/yarn-project/txe/src/state_machine/archiver.ts
+++ b/yarn-project/txe/src/state_machine/archiver.ts
@@ -92,7 +92,6 @@ export class TXEArchiver extends ArchiverDataSourceBase {
       proven: tipId,
       finalized: tipId,
       checkpointed: tipId,
-      proposedCheckpoint: tipId,
     };
   }