kill-deadcode

name	kill-deadcode
description	Find and remove dead code using Knip (expansive) + TS Language Server verification. Use when running /kill-deadcode, removing unused exports/types, or cleaning up dead code.
argument-hint	[--auto-remove] [--include-extra]

Kill Dead Code

Find dead code with Knip in expansive mode, verify each finding with grep and TS Language Server, then remove confirmed dead code.

When to Use

• Running /kill-deadcode
• Removing unused exports, types, enum members, or class members
• Cleaning up dead code

Prerequisites

The project must have (already configured in kloop-ts):

• knip installed (dependency)
• typescript-language-server installed (dependency)
• typescript installed (devDependency)
• knip.json configured at project root
• tsconfig.json at project root

Process

<skill-dir> = the directory containing this SKILL.md. Resolve once at start and reuse. <project-root> = current working directory (must contain package.json).

Step 1: Run Knip

bunx knip --reporter json

The knip.json already configures expansive mode (includeEntryExports: true, ignoreExportsUsedInFile: false).

Parse the JSON output. The structure is:

{
  "issues": [
    {
      "file": "src/types.ts",
      "exports": [{ "name": "foo", "line": 10, "col": 5 }],
      "types": [{ "name": "Bar", "line": 20, "col": 3 }],
      "nsExports": [...], "nsTypes": [...],
      "enumMembers": [...], "namespaceMembers": [...],
      "duplicates": [...],
      "files": [{ "name": "..." }],
      "dependencies": [{ "name": "..." }]
    }
  ]
}

Each issue has a file and arrays of symbols per category. Categories with line/col are verifiable (exports, types, nsExports, nsTypes, enumMembers, namespaceMembers). Categories without positions (files, dependencies, devDependencies, binaries) are not verifiable via LSP.

Step 2: Verify Each Finding

For each verifiable finding (has line + col):

2a. Quick grep check — Search for the symbol name across the codebase:

Grep: pattern="<symbol-name>", path="<project-root>/src", output_mode="content"

If the symbol appears to be clearly used in production code (not just its declaration, not only in test files), mark as false positive and skip. Usage only in *.test.ts or __tests__/ does NOT count as "used".

2b. LSP reference check — For ambiguous cases or when grep is inconclusive (re-exports, barrel files, namespace imports):

node <skill-dir>/scripts/tsp-refs.mjs <file> <line> <col>

This outputs JSON:

{ "references": N, "locations": [{ "file": "...", "line": N }] }

• references <= 1 → confirmed dead (only the declaration itself)
• references > 1 → check if ALL references are in test files (e.g. *.test.ts, __tests__/). If yes, still count as dead — usage only in tests doesn't count. If any reference is in production code (src/), mark as false positive.

Note: This spawns a new LSP process per call. For large batches, prefer grep first and only use LSP for ambiguous cases.

2c. Read for context — For anything still unclear, Read the file around the finding to understand the code structure before deciding.

Step 3: Present Findings

Show a summary table:

| Category       | Count |
|----------------|-------|
| Confirmed dead | N     |
| False positives| N     |
| Not verifiable | N     |

List each confirmed dead item:

src/types.ts:42  export function unusedHelper()
src/state.ts:15  type UnusedConfig

If --auto-remove was NOT passed, ASK the user for confirmation before proceeding.

Step 4: Remove Dead Code

For each confirmed dead item, use the Edit tool:

• Unused export function/variable: Remove the entire declaration. Check if removing it makes its imports dead too.
• Unused type/interface: Remove the entire type declaration.
• Unused enum member: Remove just the member from the enum.
• Unused class member: Remove the property or method.
• Unused export keyword only (symbol is used locally): Just remove the export keyword.

After each removal, check if any imports of the removed symbol became unused — if so, remove those imports too.

Step 5: Re-verify

After all removals:

bunx knip --reporter json

If new cascade findings appear, repeat Steps 2-4. Cascade removals are common — removing an export may reveal its import is now dead.

Step 6: Summary

Show final diff summary:

Removed N dead code items across M files:
- src/types.ts: removed 3 unused types
- src/deps.ts: removed 1 unused export
- src/cli.ts: removed 2 unused functions

Important Rules

• NEVER remove items from the "not verifiable" section (unused files, unused dependencies) without explicit user approval.
• Always check for cascade effects after removals.
• If the LSP helper fails (exit code 1), fall back to grep-only verification — do NOT assume dead.
• The tsp-refs.mjs script is at <skill-dir>/scripts/tsp-refs.mjs.
• Run bunx knip (not plain knip) to ensure the correct binary is used.