Token Pilot

Token Pilot

Token-efficient AI coding, enforced. Cuts context consumption in AI coding assistants by up to 90% without changing the way you work.

Why it matters more now: as frontier models move up in price, the tokens you don't spend reading code are worth more, not less. The savings are in tokens; the value is in tokens × price. Token Pilot keeps the expensive main thread lean so the premium model spends its budget on reasoning, not on re-reading files.

Two layers, each useful on its own, stronger together:

1. MCP tools — structural reads (smart_read, read_symbol, read_for_edit, …). Ask for an outline or load one function by name instead of the whole file.
2. PreToolUse hooks — intercept heavy native tool calls (Read on large files, recursive Grep, unbounded git diff) and redirect to token-efficient alternatives.

How It Works

Traditional:  Read("user-service.ts")  →  500 lines  →  ~3000 tokensToken Pilot:  smart_read("user-service.ts")  →  15-line outline  →  ~200 tokens              read_symbol("UserService.updateUser")  →  45 lines  →  ~350 tokens              After edit: read_diff("user-service.ts")  →  ~20 tokens

Files under 200 lines are returned in full — zero overhead for small files.

Benchmarks

Measured on public open-source repos. Files ≥50 lines only:

smart_read outline savings only. Real sessions additionally benefit from session cache, read_symbol, and read_for_edit. Reproduce: npx tsx scripts/benchmark.ts.

Quick Start

npx -y token-pilot init

Creates (or merges into) .mcp.json with token-pilot + context-mode. Restart your AI assistant to activate.

What You Get

• 25 MCP tools — structural reads, symbol search, git analysis, module routing, session analytics → tools reference
• PreToolUse hooks — block heavy Grep/Bash/Read calls; redirect to efficient alternatives → hooks & modes
• Tool profiles — trim advertised tools/list to save ~2 k tokens per session → profiles & config

Client Support Matrix

Hooks are written for Claude Code (the plugin's own hooks/hooks.json, or ~/.claude/settings.json for an npm install) and for Codex CLI (npx token-pilot install-hook --client=codex, then /hooks inside Codex to trust them). The other clients get the MCP tools; their hook systems exist but token-pilot does not write to them yet.

On Claude Code 2.1.275 and later the plugin runs its hooks inside Claude Code as a mod — no process per tool call, and a big Read comes back as an outline instead of a refusal. Older versions keep the command hooks → Claude Code mods

Manual config snippets for each client → installation guide

Enforcement Mode

TOKEN_PILOT_MODE controls how aggressively Token Pilot redirects heavy native tool calls:

TOKEN_PILOT_MODE=strict npx token-pilot

→ Full hook & mode docs

Ecosystem

Token Pilot owns input tokens — the stuff Claude reads from files, git, search. The other half of a session (what Claude writes back, how it executes code, how it remembers state across days) is owned by separate tools. They compose cleanly:

A session that pairs token-pilot + caveman typically hits ~85-90% total reduction — each cuts a different half, no overlap. Install what you need; none of them assume the others are present.

→ full ecosystem map

Rules of thumb: read code → smart_read/read_symbol; execute code with big output → context-mode execute; bash-only agent → ast-index CLI. Never copy the whole stack into CLAUDE.md — Token Pilot's doctor warns when CLAUDE.md exceeds 60 lines.

Supported Languages

TypeScript, JavaScript, Python, Go, Rust, Java, Kotlin, C#, C/C++, PHP, Ruby. Non-code (JSON/YAML/Markdown/TOML) gets structural summaries. Regex fallback handles most other languages.

Update / New Machine

Claude Code (plugin — recommended):

# Install on a new machine:claude plugin marketplace add https://github.com/Digital-Threads/token-pilotclaude plugin install token-pilot@token-pilot
# Update to latest:claude plugin update token-pilot

Other clients (Cursor, Codex, Cline, …):

# Install on a new machine:npx -y token-pilot init
# Update to latest — npx always pulls fresh, just restart your client.# Or if installed globally:npm i -g token-pilot@latestnpx token-pilot install-hook

Tips for Claude Code 2.1.139+

The May 2026 Claude Code update changed a few things that affect how token-pilot is invoked. Nothing breaks on older versions — these are quality-of-life notes for the newer ones.

• Cold ast-index calls — raise MCP_TOOL_TIMEOUT. The first find_usages / outline / read_symbol on a large repo triggers an index build. Default per-MCP-tool timeout (60 s) is enough for ~50k-file repos; bigger ones benefit from MCP_TOOL_TIMEOUT=120000 in ~/.claude/settings.json. Subsequent calls hit the cache and return in ~50 ms.

• Background sessions with --mcp-config. Dispatching a worker via claude agents or --bg with --mcp-config /path/to/other.json swaps the MCP set for that session. If token-pilot is not in the override config, MCP tools (smart_read, find_usages, …) are unavailable in that worker. On a Claude Code that loads the token-pilot mod, the hooks (Read / Bash / Grep / Edit in strict mode / Agent) see the tools are missing and step aside. The command hooks of an older Claude Code only see a server turned off in /mcp. Add token-pilot to the override config if you want the tools.

• claude plugin details token-pilot. Shows the projected per-turn token cost, the hook event names, and the MCP server entry. The skill list and the LSP list are all auto-discovered from the canonical sub-folders.

Power-user — undocumented Claude Code features that pair with token-pilot

These fields come from reverse-engineering @anthropic-ai/[email protected] source (see the May 2026 Habr write-up). They work today but are not in the official Claude Code docs, so use at your own risk.

Bootstrap-once hook (once: true)

The plugin ships a SessionStart hook flagged once: true — Claude Code runs it once per project then auto-removes the entry. It surfaces a friendly hint when install-ast-index hasn't been run yet. v0.35.0+.

Async telemetry (async: true)

PostToolUse hooks (Bash, Task) are marked async: true so they no longer add wall-clock to the hot path — telemetry writes fire in the background.

Auto-mode permissions (user-side)

If you want full auto-approval for safe commands, the YOLO classifier reads natural-language environment descriptions:

{  "autoMode": {    "allow": ["Bash(git status)", "Bash(npm test)", "Read", "Grep"],    "soft_deny": ["Bash(git push *)", "Bash(rm *)", "Write(.env)"],    "environmentDescription":      "This is a development laptop. Read-only ops are safe; deny anything touching credentials or production."  }}

token-pilot's enforcement still runs on top (raw Read on large files is denied first, regardless of autoMode).

Permission rule syntax cheat-sheet

Bash(npm *)                       # wildcard after "npm "Bash(git commit *)                # specific subcommandRead(*.ts)                        # extensionRead(src/**/*.ts)                 # recursive + extensionWrite(src/**)                     # recursive all filesmcp__token-pilot                  # all token-pilot MCP toolsmcp__token-pilot__smart_read      # one specific MCP tool

* matches inside word boundaries (shell-glob); ** is recursive. The if field on hooks uses the same syntax.

Experimental: transparent Read rewrite

Set TOKEN_PILOT_HOOK_REWRITE=1 to swap the "deny + suggest" Read hook behaviour for an updatedInput rewrite — Claude Code's undocumented field that silently bounds the Read to its first 200 lines instead of bouncing the call. The structural summary still rides along in additionalContext. Default OFF because the field is undocumented and may change.

Experimental: SubagentStop budget feedback (CC 2.1.163+)

Every subagent completion lands a task-telemetry row via the SubagentStop hook (that's how stats --tasks knows what you dispatched). With TOKEN_PILOT_SUBAGENT_FEEDBACK=1 the same hook also returns additionalContext — when a token-pilot workflow fan-out is at ≥90 % of its token ceiling, each completing agent gets a wind-down note so a hundred-agent /workflow run stops before blowing the budget.

Requires Claude Code 2.1.163+. Returning additionalContext from SubagentStop is only honoured there; older Claude Code labels it a hook error. Default OFF for that reason — enable only once claude --version reports 2.1.163 or later.

What's new for Claude Code 2.1.151+

These notes are about behaviour you'll see automatically once you update both Claude Code and token-pilot@latest. No extra configuration required.

Session title badge ([TP] Nk saved)

The SessionStart hook now sets the window/tab title to the cumulative token savings for the current project, using Claude Code 2.1.152's hookSpecificOutput.sessionTitle field. You'll see a badge like [TP] 1.2M saved in the title bar so you can confirm at a glance that the plugin is doing its job.

Hardened skills (disallowed-tools)

The three bundled skills (guide, install, stats) declare disallowed-tools (Claude Code 2.1.152+) so a runaway model can't issue Write / Edit / Task while the skill is on display. The install skill keeps Bash because it has to run npx token-pilot install-ast-index; the other two have Bash disallowed too.

Auto mode on third-party providers

Claude Code 2.1.158 opened auto mode to Bedrock / Vertex / Foundry on Opus 4.7 + 4.8. If you're on one of those, opt in with CLAUDE_CODE_ENABLE_AUTO_MODE=1. token-pilot's deny-Read / deny-Bash gates still run on top — auto mode never bypasses them.

Fleet workflows (v0.38.0)

When you fan a task across many subagents — via Claude Code's /workflow, the Agent tool, or your own orchestration — token-pilot can treat the whole run as one budgeted, telemetry-tagged unit.

token-pilot owns the workflow boundary, so this works regardless of whether Claude Code propagates a workflow id. You wrap the batch:

# Start a workflow — prints an export line you eval into your shelleval "$(token-pilot workflow start "review every PR from last sprint" --budget=2000000)"
# ...now run your fan-out work. Every hook event is tagged with the#    workflow id automatically (TOKEN_PILOT_WORKFLOW_ID is set).
token-pilot workflow status      # live budget + task countstoken-pilot workflow list        # all recorded workflowstoken-pilot workflow end         # stamp it finished + print summary

While a workflow is active:

• Every event:"task" / denied / diagnostic row in hook-events.jsonl carries workflow_id, so you can slice one fan-out run out of the global log.
• The PreToolUse:Agent hook watches the token ceiling. At ≥90 % it adds a wind-down note ("finish in-flight work rather than starting new branches") and logs a workflow_near_budget diagnostic — visible in workflow status. Dispatch is never hard-blocked on budget (a half-finished fan-out is worse than a small overrun).
• The window title switches to [TP] wf · N tasks · X% so a long run shows live progress.

Claude Code's own /workflow (2.1.154+) does not expose a per-workflow id env var to subagents (verified against the 2.1.161 bundle — it has only a CLAUDE_CODE_WORKFLOWS feature flag). So token-pilot's workflows are independent: they rely on our own TOKEN_PILOT_WORKFLOW_ID. If CC adds a per-workflow env var later, activeWorkflowId() already probes for it — no config change needed.

Troubleshooting

npx token-pilot doctor          # diagnose: ast-index, config, upstream drift# "ast-index not found"  →  npx token-pilot install-ast-index# "hooks not firing"     →  restart your AI assistant

Credits

Built on ast-index · @ast-grep/cli · MCP SDK · chokidar

License

MIT