Tool reference

ScalaSemantic exposes MCP tools over stdio JSON-RPC. For most workflows, start with find_symbol to turn a plain name into a SemanticDB symbol string, then pass that symbol to the more specific query.

Tools

Tool	Use it for
find_symbol	Resolve a plain or partial name to SemanticDB symbol strings. Start here.
find_usages	Find exact references to a symbol, split by definition/reference, with paging.
method_signature	Render a method signature, including type params and implicit/using parameter lists.
class_hierarchy	Inspect parents, linearization, and known subtypes across the index.
find_overloads	List overloads that share a name and owner.
members	List declared and inherited members, override-aware.
type_at_position	Return the symbol and type at a 0-based source position.
resolve_implicits	Find given definitions that can produce a requested type.
trace_implicit_chain	Follow a given's transitive implicit dependencies.
call_path	Find the shortest known call path between two methods.
annotated_source	Read a source file with compiler-inserted type annotations.
document_outline	Survey a file's declarations (kind, line, signature) without reading the full source.
rename_plan	Produce the exact edits to rename a symbol everywhere it is used.
move_plan	Produce the edits to move a top-level definition to another package.
extract_method_plan	Produce the edits to extract a code range into a new method.
set_workspace_root	Update the session's current workspace root after a worktree or cwd change.
get_workspace_root	Report the session's current workspace root.

Results are lean by default: compact locations, one-line signatures, omitted empty fields. Use "detailed": true on tools that support it for structured breakdowns. find_usages is paged with limit and offset.

After changing working directories, call set_workspace_root with the new absolute path before any other ScalaSemantic tool. If the current state is unclear, call get_workspace_root first. This works around stdio MCP clients that keep the same server process alive across cwd/worktree changes. The active root also controls classpath discovery: the server remembers discovered .scala-semantic/classpath-*.json metadata for that root until set_workspace_root changes the root. Discovery checks direct root metadata, follows .scala-semantic/modules-*.json to child source and output directories, then scans visible subdirectories as a fallback.

SemanticDB symbol grammar

Every semantic tool takes a SemanticDB symbol string. The trailing character encodes the kind:

Terminator	Kind	Example
/	Package	com/example/
#	Type (class/trait/object)	com/example/Animal#
.	Term (val/object)	com/example/Sample.
().	Method	com/example/Sample.render().
(+1).	Overloaded method (disambiguator)	com/example/Sample.render(+1).

So com/example/Animal# is the type Animal in package com.example, and com/example/Sample.render(). is a method.

Use find_symbol to resolve a human name to its symbol; use type_at_position to get the symbol at a cursor location.

Request shape

MCP clients call tools automatically. For manual stdio checks, direct integrations, and full request/response JSON examples for every tool, see Tool Examples.