Call Builder and Writer Plugin - BlockX Docs

A Call Builder expands task input into function calls. A Writer Plugin handles their outputs. Together they connect EVM source data, your computation, and its result destination.

Choose the input

Call Builder	Input	Typical use
`BlockTableCallConfig`	Trigger-table rows at a block	Derive data for a new block
`BlockBundleCallConfig`	Source rows in a historical bundle	Backfill derived data
`InputsCallConfig`	Explicit positional argument lists	Run a function for selected entities or test inputs

A trigger-row template places source fields into function arguments. Pass chain and block context explicitly for dependency reads. Optional operators filter or deduplicate the trigger rows before function execution.

Choose the result destination

Writer Plugin	Destination	Context
`BlockTableWriteHandler`	BlockDB block table	A block on the block deployment, or a bundle on the bundle deployment
`NormalTableWriteHandler`	BlockDB normal table	Keyed records, without a block field on the handler
`ReturnValueHandler`	Caller	Collected outputs; available on the block deployment

These are the paths used by the guides. For wire fields and additional registered writers, see configuration reference.

Combinations

Computation	Call Builder	Writer Plugin
Derive records for one EVM block	`BlockTableCallConfig`	`BlockTableWriteHandler`
Backfill historical derived records	`BlockBundleCallConfig`	`BlockTableWriteHandler`
Query selected accounts or contracts	`InputsCallConfig`	`ReturnValueHandler`
Update a keyed lookup table	Any input supported by the deployment	`NormalTableWriteHandler`

Match the input and output contexts to the intended computation. A successful Writer Plugin reports its own operation; check execution semantics before consuming written data.

Summary

The Call Builder chooses input rows or arguments.
The Writer Plugin chooses the output destination and write context.
Input selection and output write context must refer to the intended block or bundle.

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