Register CN for Caplin - #844
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Register `CN` for Caplin, Erigon's embedded consensus layer client. Caplin integrates the consensus layer directly into the Erigon node, removing the need for a separate CL process and its own disk storage, which reduces operational complexity and resource usage. It is a distinct consensus client and needs its own two-letter code so that blocks proposed by an Erigon + Caplin setup are correctly attributable. `EG` is already reserved for erigon (execution layer), so it cannot be reused for the consensus layer: the graffiti client-version format (`<EL code><EL commit><CL code><CL commit>`) requires distinct codes to tell the two layers apart. With `CN`, an Erigon + Caplin block encodes as e.g. `EGa53eCNa53e`, letting client-diversity tooling measure Caplin adoption independently.
MysticRyuujin
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Jul 7, 2026
mkalinin
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Jul 7, 2026
pull Bot
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Jul 8, 2026
…ontech#22303) ## What When a validator proposes a block without specifying graffiti, Caplin now fills the graffiti with the client-version encoding from the [client identification standard](https://github.com/ethereum/execution-apis/blob/main/src/engine/identification.md) instead of the literal `"Caplin"` string: ``` <EL code><EL commit><CN><CL commit> e.g. EGa53eCNa53e ``` This lets client-diversity tooling attribute proposed blocks to both their execution and consensus clients. Today an Erigon + Caplin node leaves no execution-client fingerprint in its blocks. ## Why Execution-layer client diversity is largely unmeasurable from block data. The standard addresses this by having the consensus client embed the execution and consensus client codes and their commit prefixes in the default graffiti. Caplin previously emitted only the literal `"Caplin"`, contributing no execution-client signal. ## How - Adds `GetClientVersionV1` to the `ExecutionEngine` interface; Caplin obtains the execution client's code and commit via `engine_getClientVersionV1`. The result is cached, so steady-state block production performs no extra engine API calls. - Caplin identifies itself with the reserved consensus client code `CN`. - When the execution client does not support the method, the graffiti degrades to the consensus-client identifier only (`CN<commit>`). - User-specified graffiti is unchanged. - Deduplicates the local client-version construction into `engine_types.NewClientVersionV1` / `LocalClientVersionV1`, now shared by the engine API handler and the in-process execution client. ## Dependency Caplin's consensus client code `CN` is registered in ethereum/execution-apis#844. This change can merge independently: the encoding works before registration (consumers must accept any two-letter code), and attribution tooling recognizes `CN` once that PR lands. ## Testing - New `cl/beacon/handler/block_production_graffiti_test.go`: encoding, execution-client-unavailable fallback, no-engine fallback, and cache behavior (the engine is queried once across multiple proposals). - `make lint`, `go vet`, and the affected package tests pass.
nflaig
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Jul 9, 2026
Add client code for Caplin and Nimbus-EL per ethereum/execution-apis#844 and ethereum/execution-apis#848
jihoonsong
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Jul 16, 2026
Register `CN` for Caplin, Erigon's embedded consensus layer client. Caplin integrates the consensus layer directly into the Erigon node, removing the need for a separate CL process and its own disk storage, which reduces operational complexity and resource usage. It is a distinct consensus client and needs its own two-letter code so that blocks proposed by an Erigon + Caplin setup are correctly attributable. `EG` is already reserved for erigon (execution layer), so it cannot be reused for the consensus layer: the graffiti client-version format (`<EL code><EL commit><CL code><CL commit>`) requires distinct codes to tell the two layers apart. With `CN`, an Erigon + Caplin block encodes as e.g. `EGa53eCNa53e`, letting client-diversity tooling measure Caplin adoption independently.
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Register
CNfor Caplin, Erigon's embedded consensus layer client.Caplin integrates the consensus layer directly into the Erigon node, removing the need for a separate CL process and its own disk storage, which reduces operational complexity and resource usage. It is a distinct consensus client and needs its own two-letter code so that blocks proposed by an Erigon + Caplin setup are correctly attributable.
EGis already reserved for erigon (execution layer), so it cannot be reused for the consensus layer: the graffiti client-version format (<EL code><EL commit><CL code><CL commit>) requires distinct codes to tell the two layers apart. WithCN, an Erigon + Caplin block encodes as e.g.EGa53eCNa53e, letting client-diversity tooling measure Caplin adoption independently.