ContextSliver

On-demand context management for AI coding agents. Stop reading whole files — ask for the connected subgraph instead.

The problem

When you ask an AI coding agent (Claude Code, Cursor, Cline) to "fix the bug in AuthService," it repeatedly reads entire files to find the 5% that's relevant — burning 40,000–80,000 tokens on a question that needed ~3,000.

find . -name "*.ts"   → 2,000 tokens (a file listing)
cat AuthService.ts    → 3,000 tokens (whole file)
grep -r "AuthService" → 5,000 tokens (40 matches)
cat AuthMiddleware.ts → 2,500 tokens (whole file, again)
... × 10 more ...

Existing tools don't fully fix it: Graphify dumps one enormous whole-repo map into context up front; Repomix packs the entire repo into one file; Aider's repo-map sends a whole-repo summary with every message. None of them track what the agent has already seen this session.

Related MCP server: mcplens

What ContextSliver does

ContextSliver runs as a background MCP server on your machine. It indexes your codebase into a local SQLite graph of every function, class, and import. When the agent needs context, it calls an MCP tool instead of reading files:

Agent:   "What connects to AuthService? Budget: 2,000 tokens."

ContextSliver:
  symbol:        AuthService  (src/auth/AuthService.ts)
  callers:       [AuthMiddleware, LoginController]      ← who uses it
  dependencies:  [UserRepository, TokenService]         ← what it uses
  already_in_context: [UserRepository]                  ← skipped, agent already has it
  // ~380 tokens

Three things make it different:

1. On-demand pruning — never sends the whole graph, only the connected subgraph for the task.

2. Session ledger — tracks what the agent has already seen and skips re-sending it.

3. One-command setup — npx contextsliver init. No database server, no API key.

Quickstart

# In your project root:
npx contextsliver init      # creates .sliver/, .mcp.json, CLAUDE.md, indexes the repo
npx contextsliver start     # runs the MCP server + file watcher (stdio)

Then restart Claude Code / Cursor / Cline — they'll pick up the five tools automatically. See the templates for client-specific config.

The five MCP tools

Pass the session_id from your first cs_get_context call to every subsequent call to enable deduplication.

Supported languages

• TypeScript / JavaScript / TSX (v0.1)

• Python (v0.1)

• Go, Rust, Java — planned (see roadmap)

Adding a language = add a grammar package + a grammars/<lang>/tags.scm query + a fixture. See CONTRIBUTING.md.

How it works

Your codebase  ──chokidar──▶  Parser (Tree-sitter)  ──▶  SQLite graph (.sliver/index.db)
                                                                    │
                              MCP server (stdio) ◀──────────────────┘
                                    │   session ledger (.sliver/sessions.db)
                                    ▼
                          Claude Code / Cursor / Cline

• Parser: Tree-sitter extracts symbols + imports per file.

• Graph engine: stores symbol→symbol edges; bidirectional BFS (blastRadius) for blast radius with cycle detection.

• Session manager: per-session ledger computes deltas so already-sent context is skipped.

• MCP server: exposes the five tools over stdio.

Token counting

Counts use gpt-tokenizer (cl100k_base) and are labeled ~approximate — close enough for budget guidance, not billing.

Development

npm install
npm test            # unit + integration tests
npm run test:bench  # indexing benchmarks
npm run build       # tsc → dist/
npm run lint        # eslint

Requires Node ≥ 20.

Roadmap

• v0.1 ✅ TS/JS + Python, SQLite graph, session ledger, 5 tools, CLI, watcher

• v0.2 — incremental indexing polish, Cursor integration, CI benchmarks

• v0.3 — Go + Rust, monorepo workspace resolution, language-plugin docs

• v0.4 — PreToolUse hook, Java, published token-reduction benchmarks

• v0.5 — Streamable HTTP transport, DuckDB backend for 50k-file repos, PageRank ranking

• v1.0 — frozen API, optional native (napi-rs) engine, SCIP/LSP precision backend

See contextsliver-spec.md for the full specification.

License

MIT © Muneeb Ur Rehman