ReScript — 173 Operations for AI Agents

This page is the canonical reference an AI coding agent uses to refactor, query, and analyze ReScript code through the act MCP server. 173 operations available: 99 refactor, 18 query, 42 analysis, 14 verification. Each operation is callable from Claude Code, Cursor, Codex, OpenCode, or any MCP-compatible agent host. Click any operation for a stable anchor link suitable for citation.

18Query
99Refactor
42Analysis
14Verify

Query

18 query tools, the same on every supported language. Descriptions live in the shared reference: /docs/query-tools.

callers control_flow data_flow definition diagnostics effect_closure effect_summary fix_auto get_type graph import_organize interface mutations references repo_outline skeleton symbols symbols_batch

Refactor

Operation Description
add-error-handling-to-promise Add .catch() to a promise chain
add-export-declaration Mark a symbol as exported (adds interface annotation comment)
add-import Add an open statement for a module
add-import-alias Add a module alias declaration: module Alias = ModulePath
add-missing-cases Add missing switch cases
add-missing-record-fields Add missing required fields to a record literal
add-module-open Prepend an open statement at the top of the file
add-option-annotation Add option<type> annotation to a binding
add-result-annotation Add result<ok_type, err_type> annotation
add-return-type-annotation Add return type annotation to a function
add-try-catch-around-await Wrap async operation in try-catch
add-type-annotation Add a type annotation to a let binding
add-type-annotation-to-param Add type annotation to a function parameter
convert-callback-to-promise Wrap callback-based function in a Promise
convert-concat-to-template-literal Convert ++ string concatenation to a template literal
convert-curried-to-uncurried Convert a curried function (a => b => body) to uncurried form (. a, b) => body
convert-exception-to-result Wrap an exception-raising expression in a result type
convert-for-loop-to-array-filter Convert a for-in loop to an Array.filter call
convert-for-loop-to-array-map Convert a for-in loop to an Array.map call
convert-for-loop-to-array-reduce Convert a for-in loop to an Array.reduce call
convert-for-loop-to-list-map Convert for loop to List.map
convert-if-else-to-switch Convert an if-else chain to a switch expression
convert-if-to-ternary Convert an if-else expression to a ternary (cond ? a : b)
convert-imperative-to-functional Convert imperative mutation to functional pipeline
convert-let-to-ref Convert a let binding to a mutable ref cell
convert-null-to-none Replace Js.null / null with None
convert-nullable-to-option Wrap a nullable JS value in option
convert-positional-to-labeled-args Convert positional function parameters to labeled (~param) form
convert-promise-chain-to-async Convert .then() chain to async/await
convert-record-to-variant Convert a record type definition to a variant
convert-ref-to-let Convert a ref cell back to an immutable let binding
convert-switch-to-if-else Convert a switch expression to an if-else chain
convert-ternary-to-if Convert a ternary expression to an if-else block
convert-to-option-pattern-match Generate a switch pattern match for an Option variable
convert-to-result-for-safety Wrap a fallible expression in a result type
convert-to-result-pattern-match Convert try-catch to pattern match on result
convert-uncurried-to-curried Convert an uncurried function (. a, b) => body to curried form a => b => body
convert-while-to-recursion Convert while loop to tail-recursive function
extract-condition-to-variable Extract complex condition to named binding
extract-constant Extract a literal or expression into a top-level constant binding
extract-function Extract selected lines into a new named function
extract-record-type Extract an inline record literal to a named type
extract-variable Extract an expression into a new local let binding
extract-variant-type Extract an inline variant to a named type
extract_function Extract a code selection into a new function — automatically infers parameters, return types, and inserts the call site. Use instead of manually cutting/pasting code. Works without LSP; LSP improves type inference. Params: file (string), new_name (string), start_line (u32), start_column (u32), end_line (u32), end_column (u32) [, preview (bool), receipt (bool)]
extract_variable Extract an expression into a named variable — inserts the declaration and replaces the expression with the variable name. Works without LSP. Params: file (string), new_name (string), start_line (u32), start_column (u32), end_line (u32), end_column (u32) [, preview (bool)]
generate-accessor-functions Generate getter accessor functions for each record field
generate-documentation-comment Generate a doc comment block above a binding
generate-equality-function Generate a structural equality function for a type
generate-external-binding Generate a @external binding
generate-function-stub Generate a function stub with Js.log("TODO") body
generate-impl-stubs Generate implementation stubs inside a module block
generate-module-type Generate a module type signature block
generate-option-wrapper Generate an option<'a> wrapper
generate-record-constructor Generate a type declaration for a record type
generate-record-creator Generate a maker function (makeRecord) for a record type
generate-record-type Generate a record type definition from field descriptions
generate-record-updater Generate an updater function for a record
generate-result-wrapper Generate a result<'a, string> error wrapper function
generate-send-binding Generate a @send method binding
generate-string-representation Generate a typeToString conversion function
generate-test-case Generate a single test(...) case with Arrange/Act/Assert comments
generate-type-definition-docs Generate a doc comment for a type
generate-unit-test-scaffold Generate a describe/test scaffold for a module
generate-variant-matcher Generate a pattern match function for a variant
generate-variant-type Generate a variant type definition
inline Inline a variable, function, or method — replace every usage with its definition body, then remove the original. The inverse of extract. Works without LSP (single-file); LSP enables cross-file inlining. Params: file (string), symbol (string) [, line (u32), preview (bool), receipt (bool)]
inline-constant Inline a named constant by replacing all references with its value
inline-variable Inline a let-bound variable by replacing uses with its value
insert_body Replace a function's implementation body with new code. AST-validated — rejects if the result has parse errors, so you can't accidentally break syntax. Use instead of manual text editing for function rewrites. Params: file (string), symbol (string), code (string) [, commit (bool)]
introduce-local-binding Insert a new let binding at the specified line
introduce-named-constant Extract a literal expression into a named top-level constant
introduce-parameter-from-local Promote a local binding to a function parameter
invert-if-condition Invert the condition of an if-else
join-adjacent-strings Merge adjacent string literals joined with ++
make-field-optional Make a record field optional (option<'a>)
move-to-module Move a symbol into a qualified module path
move_symbol Move a function, class, or type to a different file and automatically update all imports across the codebase. Use instead of manually cut/paste + fixing imports. Works without LSP (single-file); LSP enables cross-file import updates. Params: file (string), symbol (string), destination (string) [, preview (bool), receipt (bool)]
organize-imports Sort and deduplicate open statements alphabetically
recipe_run Run a codemod recipe: declarative match → transform → optional verify across modeled grammars. Preview lists matches; apply writes with optional E7 receipts and all-or-nothing rollback. Returns a per-site report.
remove-dead-code Remove unused declarations
remove-import Remove an open statement for a module
remove-module-open Remove a specific open statement from the file
remove-unnecessary-else Remove else branch after early return
remove-unused-parameter Remove a parameter that is never used in the function body
rename Rename a symbol and automatically update ALL references across the codebase. Safer and faster than find-and-replace — AST-aware, won't rename strings or comments. Works without LSP (single-file); LSP enables cross-file renames. Params: file (string), old_name (string), new_name (string) [, line (u32), column (u32), preview (bool), receipt (bool)]
rename-identifier Rename a variable, function, or binding across its scope
rename-record-field Rename a field in a record type definition
reorder-parameters Reorder the parameters of a function definition
use-option-flat-map Convert nested option map to flatMap
use-option-get-or Convert switch on option to Option.getOr
use-option-instead-of-if Replace an Option null-check if-statement with Option.isSome / Option.isNone
use-option-map Convert switch on option to Option.map
use-record-shorthand Convert {x: x} to {x} shorthand
use-result-flat-map Convert nested result map to flatMap
use-result-map Convert switch on result to Result.map
use-spread-operator Convert manual field copies to record spread
wrap-in-option-for-safety Wrap a potentially-missing value binding in Option
wrap-value-in-option Wrap an expression in Some(...)

Analysis

42 analysis tools, the same on every supported language. Descriptions live in the shared reference: /docs/analysis-tools.

analyze_api_diff analyze_chokepoints analyze_clones analyze_clusters analyze_cohesion analyze_conformance analyze_coupling analyze_cycle_risk analyze_cycles analyze_dead_code analyze_depth analyze_entry_points analyze_export analyze_extraction analyze_fan_balance analyze_features analyze_hotspots analyze_impact analyze_inconsistencies analyze_inheritance analyze_interface_bloat analyze_interfaces analyze_layers analyze_orphan_types analyze_patterns analyze_platform_deps analyze_readiness analyze_roles analyze_seams analyze_stability analyze_surface analyze_test_gaps analyze_thickness analyze_type_completeness churn_hotspots co_change_clusters coverage_overlay ownership_map profile_overlay simulate split_module trace_overlay

Verify

14 verify tools, the same on every supported language. Descriptions live in the shared reference: /docs/verification.

bisect_regression gate generate_test_harness scan secret_surface summarize_pr taint_flow unsafe_surface verify_behavioral_equivalence verify_contract_preserved verify_diff_semantics verify_port_parity verify_side_effects verify_test_impact

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