Lsp Extract Function

What it does

When your agent uses it

• Agent Workflows work in your project

Example prompts

• “/lsp-extract-function”

Requirements

• Python 3
• Compatibility (from SKILL.md): Requires the agent-lsp MCP server (github.com/blackwell-systems/agent-lsp)
• Pre-approved tools (allowed-tools): mcp__lsp__list_symbols, mcp__lsp__suggest_fixes, mcp__lsp__execute_command, mcp__lsp__apply_edit, mcp__lsp__get_diagnostics, mcp__lsp__open_document, mcp__lsp__format_document, mcp__lsp__get_server_capabilities

Workflow steps

5 steps, taken from the step headings in SKILL.md.

1. 1Get context (document symbols)
2. 2Check server capabilities
3. 3Primary path: LSP code action
4. 4Manual fallback
5. 5Validate

What it can do on your machine

Read from SKILL.md and the folder at commit 09ea99e. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • mcp__lsp__list_symbols
  • mcp__lsp__suggest_fixes
  • mcp__lsp__execute_command
  • mcp__lsp__apply_edit
  • mcp__lsp__get_diagnostics
  • mcp__lsp__open_document
  • mcp__lsp__format_document
  • mcp__lsp__get_server_capabilities

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md.

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Requires the agent-lsp MCP server (github.com/blackwell-systems/agent-lsp)

  From compatibility in the SKILL.md frontmatter.

Context cost

Lsp Extract Function loads about 2k tokens when it runs, and up to ~2.5k if it reads all its reference files. Until then it costs about 73 tokens; SKILL.md has 713 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~73

When it runs · the whole SKILL.md, loaded when a task matches

~2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from blackwell-systems/agent-lsp at commit 09ea99e, republished under its MIT licence (© blackwell-systems). 713 words, ~1,987 tokens.

name

lsp-extract-function

description

Extract a selected code block into a named function. Primary path uses the language server's extract-function code action; falls back to manual extraction when no code action is available. Validates captured variables, scope shadowing, and compilation after extraction.

allowed-tools

mcp__lsp__list_symbols, mcp__lsp__suggest_fixes, mcp__lsp__execute_command, mcp__lsp__apply_edit, mcp__lsp__get_diagnostics, mcp__lsp__open_document, mcp__lsp__format_document, mcp__lsp__get_server_capabilities

compatibility

Requires the agent-lsp MCP server (github.com/blackwell-systems/agent-lsp)

argument-hint

[file-path] [start-line] [end-line] [new-function-name]

user-invocable

true

license

MIT

metadata.required-capabilities

codeActionProvider

metadata.optional-capabilities

documentFormattingProvider documentSymbolProvider

mcp__lsp__open_document({ "file_path": "<file_path>" })
mcp__lsp__list_symbols({ "file_path": "<file_path>" })

mcp__lsp__get_server_capabilities({})

mcp__lsp__suggest_fixes({
  "file_path": "<file_path>",
  "start_line": N,
  "start_column": 1,
  "end_line": M,
  "end_column": 999
})

mcp__lsp__get_diagnostics({ "file_path": "<file_path>" })

mcp__lsp__format_document({ "file_path": "<file_path>" })

## Extraction Summary
- File:           path/to/file.go
- Extracted:      lines N–M
- New function:   new_function_name
- Path used:      LSP code action / Manual fallback
- Post-extraction errors: 0

© blackwell-systems, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/lsp-extract-function of blackwell-systems/agent-lsp.

• SKILL.md
• references/patterns.md

Open the folder on GitHubat commit 09ea99e