LSP Validation Skill

LSP Validation Skill

Use the LSP (Language Server Protocol) tools to validate code quality, find references, navigate definitions, and perform safe refactoring.

Available LSP Tools

1. lsp_diagnostics - Get Errors and Warnings

When to use: After writing or modifying code to check for errors.

lsp_diagnostics(filePath: "/​path/​to/​file.ts", severity: "error")

Severity levels:

• error - Only errors (compilation failures)
• warning - Errors and warnings
• information - Includes informational messages
• hint - All diagnostics including hints
• all - Everything

Example output:

Line 42: Cannot find name 'undefined_variable' (error)
Line 58: 'foo' is declared but never used (warning)

2. lsp_goto_definition - Jump to Definition

When to use: To find where a symbol is defined.

lsp_goto_definition(filePath: "/​path/​to/​file.ts", line: 10, character: 15)

Returns the file and location where the symbol at that position is defined.

3. lsp_find_references - Find All Usages

When to use: Before refactoring to understand impact.

lsp_find_references(filePath: "/​path/​to/​file.ts", line: 10, character: 15, includeDeclaration: true)

Returns all locations where the symbol is used across the workspace.

4. lsp_rename - Safe Refactoring

When to use: To rename a symbol across the entire codebase.

lsp_rename(filePath: "/​path/​to/​file.ts", line: 10, character: 15, newName: "betterName")

Applies the rename across all files that reference the symbol.

Validation Workflow

After Writing Code

1. Write/​edit code
2. Run lsp_diagnostics with severity: "error"
3. If errors found:
   - Fix the errors
   - Re-run diagnostics
4. Run lsp_diagnostics with severity: "warning"
5. Address warnings if appropriate

Before Committing

1. Run lsp_diagnostics on all modified files
2. Ensure no errors
3. Review warnings
4. Proceed with commit only if clean

Before Refactoring

1. Use lsp_find_references to understand impact
2. Review all usages
3. If safe, use lsp_rename for symbol renaming
4. Or manually edit with confidence knowing all locations

Agent Integration

Agents That MUST Use LSP

Agents That SHOULD Use LSP

Best Practices

1. Always validate after editing - Run diagnostics after any code change
2. Check before declaring done - Ensure zero errors before completing a task
3. Use references before deleting - Never remove code without checking references
4. Prefer lsp_rename over find-replace - It's safer and handles all cases
5. Check the right severity - Use "error" for blockers, "warning" for quality

Error Handling

If LSP is unavailable for a file type:

• Fall back to running the appropriate type checker (tsc, pyright, etc.)
• Use build commands to verify compilation
• Note the limitation in your response

Supported Languages

The LSP tools work with any language that has a configured language server:

• TypeScript/​JavaScript (tsserver)
• Python (pyright, pylsp)
• Go (gopls)
• Rust (rust-analyzer)
• And many more...