vs-token-safer — dead-code elimination (preview only)

vs-token-safer — dead-code elimination (preview only)

Topological dead-code analysis built on the OFFICIAL language-server call graph (clangd / Roslyn / tsserver / pyright). You name seed symbol(s); it walks callers/callees to a fixpoint and classifies every reachable symbol. The output is token-capped (names + file:line, no source bodies). Nothing leaves the machine.

How to run

Prefer the vts_admin MCP tool (it runs in the warm server process; vts is often not on PATH in Bash). Fall back to the bundled CLI via node:

vts_admin { "op": "dce", "params": { "seed": "Foo", "projectPath": "<root>" } }
# several seeds:  "params": { "seeds": "Foo,Bar", "projectPath": "<root>", "entry": "main,registerPlugin" }
# CLI fallback:   node "$CLAUDE_PLUGIN_ROOT/server/cli.js" dce --seed Foo --projectPath <root>

Warm-index requirement (C++/clangd). The call graph must be warm. A cold or large clangd tree (e.g. an Unreal monorepo, ~26k TUs) under-reports callers, so a live symbol could look DEAD — dce therefore REFUSES on a cold clangd index. Scope + build first: vts setup --scope Source then vts preindex (or keep the MCP server warm), then re-run. allowCold=true inspects a cold index with every verdict forced to INCONCLUSIVE (never DEAD). TypeScript/Python/C# index on open and are not gated.

Show the result verbatim. Buckets: DEAD (no live caller, in safe deletion order) · HELD (still called) · ENTRY (kept root: main / public API / a name passed via entry) · INCONCLUSIVE (unresolved or the caller set couldn't be proven complete).

Two modes. Default = caller-cascade (start from seeds, follow callers). Pass roots to switch to reachability / mark-sweep (the Go-deadcode/RTA model): liveness is computed FORWARD from the named entry points, so a missing caller can't cause a false DEAD — only an incomplete root set can (the reference verify catches it). Roots are framework-agnostic — name them (roots="main,RunTests") or commit a team-curated .vts-index/dce-roots.json. vts hard-codes NO framework markers (no UFUNCTION / @Route / [Test]); you declare your own entry points, the same charter-pure mechanism as the committable concept-synonyms file.

The safety model — it NEVER deletes

dce only PROPOSES candidates from the call graph. The actual removal goes through safe_delete (vts safe-delete --symbol <name> --apply), which independently re-checks find_references and refuses while the symbol is still referenced. So a wrong DEAD candidate cannot delete live code: dce proposes, safe_delete disposes.

Karpathy-style rules — do the listed thing, do not improvise:

1. Run dce with the seed(s); show the buckets verbatim.
2. To remove a DEAD candidate, run safe_delete on it, top of the list first, one at a time.
3. Always surface the CAVEAT: the call graph does not see non-call references (function-as-value, reflection, string/dynamic dispatch, cross-language, or test-only usage). Treat DEAD as candidates, not a verdict.
4. Never bypass safe_delete (no sed/manual deletion of a DEAD candidate) — its reference guard is the backstop.

Env: VTS_DCE_MAX_NODES (cascade node cap, default 120).