lsp-generate

Requires the agent-lsp MCP server.

lsp-generate

lsp-generate creates NEW code that does not yet exist in the file — stubs, mocks, implementations of interfaces, test functions. It is distinct from lsp-extract-function, which restructures code that already exists. Use lsp-generate when you want the language server to write something new; use lsp-extract-function when you want to reorganize existing code.

Input

• file_path: absolute path to the target file
• line, column (or position_pattern): position in the file where generation is triggered (e.g., the line with the unimplemented interface, the missing method error, the type declaration)
• intent: description of what to generate (e.g., "implement io.Reader", "generate test skeleton", "add missing methods", "generate mock for Handler")

Prerequisites

LSP must be running for the target workspace. If not yet initialized, call mcp__lsp__start_lsp with the workspace root before proceeding.

Auto-init note: agent-lsp supports workspace auto-inference from file paths. Explicit start_lsp is only needed when switching workspace roots.

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Workflow

Step 1 — Open document and locate position

Call mcp__lsp__open_document for the target file:

mcp__lsp__open_document(file_path: "/abs/path/to/file.go", language_id: "go")

If using position_pattern, use the @@ marker convention from references/patterns.md to identify the exact cursor position. For example:

"position_pattern": "var _ io.Reade@@r = (*MyType)(nil)"

Step 2 — Get code actions at target position

mcp__lsp__suggest_fixes({
  "file_path": "...",
  "start_line": N,
  "start_column": C,
  "end_line": N,
  "end_column": C
})

Filter for generator actions:

• Kind "quickfix" with titles matching the intent (e.g., "Implement interface", "Generate", "Add stub", "Create test")
• Kind "source" for source-level generation

If no matching action is found, report "No generator action available at this position for the given intent" and proceed to the Fallback section below.

Step 3 — Select and confirm action

Display available generator actions to the user. If multiple actions match the intent, list all of them and ask which to apply. Confirm the selected action before executing — do NOT auto-select when multiple candidates exist.

Step 4 — Execute generator

Execute one generator at a time. Do NOT batch multiple execute_command calls.

• If the action has a command field: run via mcp__lsp__execute_command
• If the action has an edit field: apply via mcp__lsp__apply_edit
• If the action has both: apply the edit first, then run the command

Step 5 — Format and verify

mcp__lsp__format_document({ "file_path": "..." })
mcp__lsp__get_diagnostics({ "file_path": "..." })

Report remaining diagnostics. Stub methods typically leave TODO comments or panic("not implemented") bodies — this is expected behavior from the language server. Surface any unexpected errors.

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Per-Language Generator Patterns

Language	Generator	Trigger location	Code action kind
Go (gopls)	Implement interface	Line with var _ MyInterface = (*MyType)(nil) or type declaration	quickfix — "Implement interface"
Go (gopls)	Generate test file	Any .go file without _test.go counterpart	source — "Generate unit tests"
Go (gopls)	Add missing method	Line with undefined: method error	quickfix
TypeScript (typescript-language-server)	Implement interface	Class declaration	quickfix — "Implement interface members"
TypeScript (typescript-language-server)	Add missing method	Method call with no definition	quickfix — "Add missing function declaration"
Python (pyright)	Add import	Name not defined	quickfix — "Add import"
Rust (rust-analyzer)	Implement trait	impl Trait for Type {}	quickfix — "Add missing impl members"

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Fallback When No Code Action Is Available

If suggest_fixes returns no generator actions, the language server at this workspace may not support server-side generation for this intent. Explain this to the user and suggest a manual approach specific to the intent:

• Interface implementation: Look up the interface definition first using mcp__lsp__go_to_symbol to discover all required methods, then implement them manually.
• Test skeleton: Check mcp__lsp__get_server_capabilities to confirm whether the server advertises code action support; if not, generate the test skeleton manually using standard testing package conventions.
• Missing methods: Use mcp__lsp__get_diagnostics to enumerate the missing symbols by name, then implement them one at a time.

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Constraints

• Do NOT batch execute_command calls — run one generator at a time
• Do NOT skip user confirmation when multiple generator actions are available