CRE: Finalized Read Notes

public/changelog.json

@@ -406,6 +406,13 @@
     }
   },
   "data": [
+    {
+      "category": "deprecation",
+      "date": "2026-10-13",
+      "description": "CRE no longer supports the T-REX Testnet. T-REX is shutting down its testnet, so the CRE integration has been turned off. Remove T-REX Testnet from your workflow configurations and deploy to a supported network instead. See [Supported Networks](https://docs.chain.link/cre/supported-networks) for the current list.",
+      "title": "CRE deprecated on T-REX Testnet",
+      "topic": "CRE"
+    },
     {
       "category": "update",
       "date": "2026-10-12",

src/content/cre/concepts/finality-go.mdx

@@ -64,6 +64,17 @@ For most read operations, use the standard confidence levels by passing `-2` (la
 
 **Note:** The `SAFE` confidence level is not available for chain reads—only `LATEST` and `FINALIZED` are supported.
 
+{/* prettier-ignore */}
+<Aside type="caution" title="Finalized and safe reads can fail on some chains">
+  While RPC nodes are not archival nodes, they should keep sufficient blocks in memory to include `finalized` and `safe`
+  tags. However, periodically some chains experience situations where `finalized` and `safe` is not in memory because the
+  gap exceeds the normal environment. When this happens, calls to `finalized` and/or `safe` blocks will return an error.
+
+The following chains have exhibited this behavior and safe and finalized reads may periodically return errors.
+**Mainnet:** Polygon, Mantle, Scroll. **Testnet:** Polygon Amoy, Linea Sepolia.
+
+</Aside>
+
 ### Custom block depths
 
 For use cases requiring fixed confirmation thresholds or historical state verification, you can specify **any explicit block number** instead of using the predefined confidence levels. This enables you to:

src/content/cre/concepts/finality-ts.mdx

@@ -64,6 +64,17 @@ For most read operations, use the standard confidence levels by passing [`LATEST
 
 **Note:** The `SAFE` confidence level is not available for chain reads—only `LATEST` and `FINALIZED` are supported.
 
+{/* prettier-ignore */}
+<Aside type="caution" title="Finalized and safe reads can fail on some chains">
+  While RPC nodes are not archival nodes, they should keep sufficient blocks in memory to include `finalized` and `safe`
+  tags. However, periodically some chains experience situations where `finalized` and `safe` is not in memory because the
+  gap exceeds the normal environment. When this happens, calls to `finalized` and/or `safe` blocks will return an error.
+
+The following chains have exhibited this behavior and safe and finalized reads may periodically return errors.
+**Mainnet:** Polygon, Mantle, Scroll. **Testnet:** Polygon Amoy, Linea Sepolia.
+
+</Aside>
+
 ### Custom block depths
 
 For use cases requiring fixed confirmation thresholds or historical state verification, you can specify **any explicit block number** instead of using the predefined confidence levels. This enables you to:

src/content/cre/guides/workflow/using-evm-client/forwarder-directory-go.mdx

@@ -117,7 +117,7 @@ The tables below reflect chains commonly enabled for simulation. Your tenant may
 | Sonic Testnet               | <CopyText text="sonic-testnet" code/>                         | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
 | Stable Testnet              | <CopyText text="stable-testnet" code/>                        | <CopyText text="0x9081624a30231767C3093A5F2Ae1C57A4457C88F" code/> |
 | TAC Testnet                 | <CopyText text="tac-testnet" code/>                           | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
-| T-REX Testnet               | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x53bC8B33F9Fd9cf5323b260CC078967cC3f30297" code/> |
+| T-REX Testnet (deprecated)  | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x53bC8B33F9Fd9cf5323b260CC078967cC3f30297" code/> |
 | Unichain Sepolia            | <CopyText text="ethereum-testnet-sepolia-unichain-1" code/>   | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
 | World Chain Sepolia         | <CopyText text="ethereum-testnet-sepolia-worldchain-1" code/> | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
 | XLayer Testnet              | <CopyText text="xlayer-testnet" code/>                        | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
@@ -188,7 +188,7 @@ These `KeystoneForwarder` addresses are used by deployed workflows. Use these ad
 | <a href="https://explorer.testnet.soniclabs.com/address/0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" target="_blank" rel="noopener noreferrer">Sonic Testnet</a>           | <CopyText text="sonic-testnet" code/>                         | <CopyText text="0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" code/> |
 | <a href="https://testnet.stablescan.xyz/address/0x701d026D1c85BA1DCbc3EEbe3636D646D88a0Aae" target="_blank" rel="noopener noreferrer">Stable Testnet</a>                  | <CopyText text="stable-testnet" code/>                        | <CopyText text="0x701d026D1c85BA1DCbc3EEbe3636D646D88a0Aae" code/> |
 | <a href="https://spb.explorer.tac.build/address/0x7BCcaFBD064cB3658476066Cc33ceE3F3414c04c" target="_blank" rel="noopener noreferrer">TAC Testnet</a>                     | <CopyText text="tac-testnet" code/>                           | <CopyText text="0x7BCcaFBD064cB3658476066Cc33ceE3F3414c04c" code/> |
-| <a href="https://explorer.ingen.t-rex.network/address/0x8E6E6A1f2B2D4dF503bfd67951CF28F27BF3AF19" target="_blank" rel="noopener noreferrer">T-REX Testnet</a>             | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x8E6E6A1f2B2D4dF503bfd67951CF28F27BF3AF19" code/> |
+| T-REX Testnet (deprecated)                                                                                                                                                | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x8E6E6A1f2B2D4dF503bfd67951CF28F27BF3AF19" code/> |
 | <a href="https://sepolia.uniscan.xyz/address/0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" target="_blank" rel="noopener noreferrer">Unichain Sepolia</a>                   | <CopyText text="ethereum-testnet-sepolia-unichain-1" code/>   | <CopyText text="0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" code/> |
 | <a href="https://sepolia.worldscan.org/address/0x76c9cf548b4179F8901cda1f8623568b58215E62" target="_blank" rel="noopener noreferrer">World Chain Sepolia</a>              | <CopyText text="ethereum-testnet-sepolia-worldchain-1" code/> | <CopyText text="0x76c9cf548b4179F8901cda1f8623568b58215E62" code/> |
 | <a href="https://www.oklink.com/xlayer-test/address/0x9eF6468C5f37b976E57d52054c693269479A784d" target="_blank" rel="noopener noreferrer">XLayer Testnet</a>              | <CopyText text="xlayer-testnet" code/>                        | <CopyText text="0x9eF6468C5f37b976E57d52054c693269479A784d" code/> |

src/content/cre/guides/workflow/using-evm-client/forwarder-directory-ts.mdx

@@ -117,7 +117,7 @@ The tables below reflect chains commonly enabled for simulation. Your tenant may
 | Sonic Testnet               | <CopyText text="sonic-testnet" code/>                         | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
 | Stable Testnet              | <CopyText text="stable-testnet" code/>                        | <CopyText text="0x9081624a30231767C3093A5F2Ae1C57A4457C88F" code/> |
 | TAC Testnet                 | <CopyText text="tac-testnet" code/>                           | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
-| T-REX Testnet               | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x53bC8B33F9Fd9cf5323b260CC078967cC3f30297" code/> |
+| T-REX Testnet (deprecated)  | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x53bC8B33F9Fd9cf5323b260CC078967cC3f30297" code/> |
 | Unichain Sepolia            | <CopyText text="ethereum-testnet-sepolia-unichain-1" code/>   | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
 | World Chain Sepolia         | <CopyText text="ethereum-testnet-sepolia-worldchain-1" code/> | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
 | XLayer Testnet              | <CopyText text="xlayer-testnet" code/>                        | <CopyText text="0x6E9EE680ef59ef64Aa8C7371279c27E496b5eDc1" code/> |
@@ -188,7 +188,7 @@ These `KeystoneForwarder` addresses are used by deployed workflows. Use these ad
 | <a href="https://explorer.testnet.soniclabs.com/address/0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" target="_blank" rel="noopener noreferrer">Sonic Testnet</a>           | <CopyText text="sonic-testnet" code/>                         | <CopyText text="0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" code/> |
 | <a href="https://testnet.stablescan.xyz/address/0x701d026D1c85BA1DCbc3EEbe3636D646D88a0Aae" target="_blank" rel="noopener noreferrer">Stable Testnet</a>                  | <CopyText text="stable-testnet" code/>                        | <CopyText text="0x701d026D1c85BA1DCbc3EEbe3636D646D88a0Aae" code/> |
 | <a href="https://spb.explorer.tac.build/address/0x7BCcaFBD064cB3658476066Cc33ceE3F3414c04c" target="_blank" rel="noopener noreferrer">TAC Testnet</a>                     | <CopyText text="tac-testnet" code/>                           | <CopyText text="0x7BCcaFBD064cB3658476066Cc33ceE3F3414c04c" code/> |
-| <a href="https://explorer.ingen.t-rex.network/address/0x8E6E6A1f2B2D4dF503bfd67951CF28F27BF3AF19" target="_blank" rel="noopener noreferrer">T-REX Testnet</a>             | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x8E6E6A1f2B2D4dF503bfd67951CF28F27BF3AF19" code/> |
+| T-REX Testnet (deprecated)                                                                                                                                                | <CopyText text="t-rex-testnet" code/>                         | <CopyText text="0x8E6E6A1f2B2D4dF503bfd67951CF28F27BF3AF19" code/> |
 | <a href="https://sepolia.uniscan.xyz/address/0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" target="_blank" rel="noopener noreferrer">Unichain Sepolia</a>                   | <CopyText text="ethereum-testnet-sepolia-unichain-1" code/>   | <CopyText text="0x98B8335d29Aca40840Ed8426dA1A0aAa8677d8D1" code/> |
 | <a href="https://sepolia.worldscan.org/address/0x76c9cf548b4179F8901cda1f8623568b58215E62" target="_blank" rel="noopener noreferrer">World Chain Sepolia</a>              | <CopyText text="ethereum-testnet-sepolia-worldchain-1" code/> | <CopyText text="0x76c9cf548b4179F8901cda1f8623568b58215E62" code/> |
 | <a href="https://www.oklink.com/xlayer-test/address/0x9eF6468C5f37b976E57d52054c693269479A784d" target="_blank" rel="noopener noreferrer">XLayer Testnet</a>              | <CopyText text="xlayer-testnet" code/>                        | <CopyText text="0x9eF6468C5f37b976E57d52054c693269479A784d" code/> |

src/content/cre/guides/workflow/using-evm-client/onchain-read-go.mdx

@@ -158,6 +158,11 @@ When calling contract read methods, you must specify a block number. There are t
 
 For explicit block numbers, see [Custom block depths](#custom-block-depths) below.
 
+<Aside type="caution" title="Safe and finalized reads are unreliable on some chains">
+  Safe and finalized reads are not reliably supported on some chains. See [Finality and Confidence
+  Levels](/cre/concepts/finality-go#using-confidence-levels) for the current list before relying on `FINALIZED` reads.
+</Aside>
+
 ### Custom block depths
 
 For use cases requiring fixed confirmation thresholds (e.g., regulatory compliance) or historical state verification, you can specify an exact block number.

src/content/cre/guides/workflow/using-evm-client/onchain-read-ts.mdx

@@ -169,6 +169,11 @@ When calling `callContract()`, you can specify which block to read from:
 - **`LATEST_BLOCK_NUMBER`**: Read from the latest block
 - **Custom block number**: Use a `BigIntJson` object for custom finality depths or historical queries
 
+<Aside type="caution" title="Safe and finalized reads are unreliable on some chains">
+  Safe and finalized reads are not reliably supported on some chains. See [Finality and Confidence
+  Levels](/cre/concepts/finality-ts#using-confidence-levels) for the current list before relying on `FINALIZED` reads.
+</Aside>
+
 ```typescript
 import { LAST_FINALIZED_BLOCK_NUMBER, LATEST_BLOCK_NUMBER } from "@chainlink/cre-sdk"