[FEATURE] Add completion operation to the LSP tool

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When exploring library/dependency APIs, there's no way to ask "what methods are available on this type?" The LSP tool exposes 9 operations (goToDefinition, findReferences, hover, documentSymbol, workspaceSymbol, goToImplementation, prepareCallHierarchy, incomingCalls, outgoingCalls) but not textDocument/completion, which LSP servers like jdtls already support.

This means that to discover the API surface of a library type (e.g. HttpResponse from a Maven dependency), I have to resort to manual workarounds.

Proposed Solution

Adding a completion operation would let Claude query available members directly, e.g. trigger completion after prepared. To get the full list of methods, fields, and their signatures in one call. This is the standard way IDEs solve this problem, and the underlying LSP servers already implement it.

Alternative Solutions

• IntelliJ MCP
• unpackage the libraries and decompile

Priority

High - Significant impact on productivity

Feature Category

MCP server integration

Use Case Example

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Additional Context

_No response_