Optimized MCP server for AI coding agents. Structural codebase navigation + persistent memory engine — 97.9% accuracy at −80% tokens on tsbench.
Project description
Token Savior -- v4.3
One MCP server. One profile. 97.9% on tsbench at -80% tokens. Structural code navigation, persistent memory, and Bash output compaction for AI coding agents.
mibayy.github.io/token-savior -- project site + benchmark landing github.com/Mibayy/tsbench -- benchmark source + fixtures
Benchmark -- 96 real coding tasks (Claude Opus 4.7, May 2026)
| Plain Claude Code | With Token Savior | |
|---|---|---|
| Score | 141 / 180 (78.3%) | 188 / 192 (97.9%) |
| Active tokens / task | 17 221 | 3 395 (-80%) |
| Wall time / task | 110.6 s | 18.9 s (-83%) |
Reproduces with the optimized profile (single env var). See BENCHMARK-SUMMARY.
What's new
v4.3.0 -- bench-driven coverage push (May 2026)
Real-world bench against 7 days of transcripts (1130 Bash outputs) drove this release. Cumulative savings now sit at ~20.4 K tokens/week (19.3% match rate, 68.9% mean compaction) vs ~12 K/week on v4.2.0.
- Fixed
pytestregex: now matchespython3 -m pytest,uv run pytest, venv-prefixed forms,poetry/hatch/pdm/rye run pytest. - 5 more git compactors:
fetch,checkout,branch,worktree list,stash list. - 4 more gh compactors:
gh repo view,gh pr view,gh issue view,gh pr diff. grep,find,catcompactors. Group hits by file, strip common prefix, head/tail truncation. 83-96% savings on the fixtures.- Compound command splitter:
cd /root/foo && git statusnow compacts by picking the last meaningful segment of&&/;chains. Bails on subshells, heredocs, pipes, loops, unterminated quotes.
v4.2.0 -- coverage + hybrid mode + ts init
- 12 more compactors:
jest,vitest,eslint,biome,kubectl get/logs,aws sts/ec2/lambda/logs/iam/dynamodb/s3,npm/yarn/pnpm list,pip list/show,curl. Peaks: 91.7% onaws ec2, 95% onjestall-green. - Hybrid sandbox+compact mode. When a compactor matches but the compact
text is still bulky (> 4 KB), the hook emits the compact preview AND
sandboxes the full original. The agent can pull it via
capture_getif it needs the detail. ts init --agent {claude,cursor,gemini,codex}CLI. Detects agent settings, deep-merges the hook config, dedups by(matcher, command), prints a unified diff, backs upsettings.json, idempotent on re-run.ts_discovercross-project +format="adoption"reports TS-vs-native ratios per session with first/second-half trend.
v4.1.0 -- RTK-inspired Bash compaction + discover
- 14 Bash output compactors in a PostToolUse hook:
git status/diff/log/ push/commit/add,pytest,cargo test/build/clippy,tsc,docker ps/logs,gh run list/view. Median 63%, peak 100% (a greenpytest -qcollapses to one line). - PreToolUse Bash rewriter. Bare commands get denser variants before
execution:
git status->--porcelain=v2 --branch,tsc->--pretty false,pytest->-q --tb=line, etc. 10 safe rules, guarded against composition operators and explicit verbose flags. get_usage_statsv2. ASCII sparkline (30 d), daily breakdown table (7 d), top-tools cumulative,format="json".- New MCP tool
ts_discover. Scans~/.claude/projects/*/*.jsonltranscripts and flags missed TS opportunities (Read->Grep->Read chains, sequentialfind_symbol, edits withoutget_edit_context,memory_searchwithout priormemory_index, native shell on code files). 30-day scan in ~2.5 s on a 343 MB transcript dir.
Quick start
pip install "token-savior-recall[mcp]"
Add to your MCP config (e.g. Claude Code):
{
"mcpServers": {
"token-savior-recall": {
"command": "/path/to/venv/bin/token-savior",
"env": {
"WORKSPACE_ROOTS": "/path/to/project1,/path/to/project2",
"TOKEN_SAVIOR_CLIENT": "claude-code",
"TOKEN_SAVIOR_PROFILE": "optimized"
}
}
}
}
That's it. TOKEN_SAVIOR_PROFILE=optimized ships the Pareto-optimum
config that wins tsbench. It bundles:
tiny_plus(15 hot tools manifest)- thin inputSchema (-44% manifest)
- capture sandbox disabled
- memory hooks gated for cross-project safety
No other tuning needed.
Activation (Bash compaction + rewriting)
Bash compaction and the PreToolUse rewriter are opt-in. Two env vars and one CLI call:
export TS_BASH_COMPACT=1 # PostToolUse output compactors (34 of them)
export TS_BASH_REWRITE=1 # PreToolUse command rewriter (10 rules)
ts init --agent claude --yes # auto-merge hooks into ~/.claude/settings.json
ts init is idempotent. It detects existing hook entries, dedups by
(matcher, command), prints a unified diff, and backs up settings.json
to .bak-YYYYMMDD-HHMMSS (UTC) before writing. Supported agents:
claude, cursor, gemini, codex. Pass --dry-run to preview, or
--global to write the user-level config.
Optional audit log of every rewrite:
export TS_BASH_REWRITE_LOG=$HOME/.local/state/token-savior/rewrites.jsonl
Compactor catalog (34)
| Family | Compactors |
|---|---|
| git | status, diff, log, push/pull, commit, add, fetch, checkout, branch, worktree list, stash list |
| gh | run list, run view, pr diff, pr view, issue view, repo view |
| test/lint | pytest, jest, vitest, eslint, biome, cargo test, cargo build/clippy, tsc |
| cloud | kubectl get, kubectl logs, aws sts, aws ec2, aws lambda, aws logs, aws iam, aws dynamodb, aws s3 |
| docker | docker ps, docker logs |
| packaging | npm/yarn/pnpm list, pip list/show |
| shell catch-alls | grep, find, cat, curl |
Each compactor is a pure function (no I/O, no globals) returning a
token-efficient rendering. The dispatcher returns None when no matcher
fires, leaving the existing sandbox path untouched. Compound commands
(cd ... && cmd) fall through to the last meaningful segment.
ts_discover -- find missed TS opportunities
New MCP tool that scans your Claude Code transcripts for patterns where TS tools would have been cheaper than what the agent actually did.
ts_discover() # active project, last 30 days
ts_discover(project=None) # ALL transcript projects
ts_discover(format="adoption") # TS vs native ratio per session
ts_discover(format="adoption_json") # same, JSON
Findings: Read->Grep->Read chains, sequential find_symbol, edits
without get_edit_context, memory_search without memory_index,
native shell on code files. Args are pruned to load-bearing keys
(PII-safe). Streams JSONL with mtime fast-skip.
ts init CLI
ts init --agent claude [--global] [--dry-run] [--yes]
ts init --agent cursor
ts init --agent gemini
ts init --agent codex
Detects the target agent's settings location, deep-merges the Token
Savior hook config (PostToolUse + PreToolUse), preserves existing
hooks, dedups, prints a unified diff. Backs up to
settings.json.bak-YYYYMMDD-HHMMSS (UTC). Re-running is a no-op.
What it does
Claude Code reads whole files to answer questions about three lines, and forgets everything the moment a session ends. Token Savior fixes both, plus a third axis: it now compacts the noisy Bash output that bloats turn budgets between code reads.
It indexes your codebase by symbol -- functions, classes, imports, call
graph -- so the model navigates by pointer instead of by cat. Measured
reduction: 97% fewer chars injected across 170+ real sessions.
On top of that sits a persistent memory engine. Every decision, bugfix, convention, guardrail and session rollup is stored in SQLite WAL + FTS5
- vector embeddings, ranked by Bayesian validity and ROI, and re-injected as a compact delta at the start of the next session.
And on top of that, since v4.1, sit the Bash compactors and the PreToolUse rewriter. Bench numbers above.
Profile comparison
| Profile | Tools exposed | Manifest tokens | When to use |
|---|---|---|---|
optimized |
15 | ~1.5 KT | Recommended default -- Pareto win on tsbench |
auto |
adaptive | ~1-2 KT | Per-client telemetry-based (experimental) |
tiny |
6 | ~0.6 KT | Minimal hot loop |
lean |
51 | ~4 KT | Legacy -- broader surface |
full |
68 | ~6 KT | Everything exposed |
You probably want optimized.
Token savings
| Operation | Plain Claude | Token Savior | Reduction |
|---|---|---|---|
find_symbol("send_message") |
41M chars (full read) | 67 chars | -99.9% |
get_function_source("compile") |
grep + cat chain | 4.5K chars | direct |
get_change_impact("LLMClient") |
impossible | 16K chars | new capability |
| 96-task tsbench (Opus, plain vs ts) | 17 221 active/task | 3 395 active/task | -80% |
| 7-day Bash output bench (v4.3) | ~30 K tokens/week | ~9.6 K tokens/week | ~20.4 K/week |
Install
pip (MCP server)
pip install "token-savior-recall[mcp]"
# Optional hybrid vector search:
pip install "token-savior-recall[mcp,memory-vector]"
uvx (no venv, no clone)
uvx token-savior-recall
Claude Code one-liner
claude mcp add token-savior -- /path/to/venv/bin/token-savior
Development
git clone https://github.com/Mibayy/token-savior
cd token-savior
python3 -m venv .venv
.venv/bin/pip install -e ".[mcp,dev]"
pytest tests/ -q
Suite size: 1688 passed, 55 skipped on main. CI green on Python 3.11 / 3.12 / 3.13.
Bench it yourself
The compactor numbers above come from replaying real Claude Code
transcripts through the dispatcher. Two scripts live under scripts/:
python3 scripts/bench_compactors_real.py # match rate + mean savings
python3 scripts/bench_compactors_unmatched.py # top unmatched commands
The first walks ~/.claude/projects/*/*.jsonl, replays every Bash
output through the registry, and reports per-family savings + overall
match rate. The second buckets the unmatched commands so the next
compactor target is obvious from the histogram.
To reproduce the tsbench score:
git clone https://github.com/Mibayy/tsbench && cd tsbench
python3 generate.py --seed 42
git tag v1
python3 breaking_changes.py
git tag v2
TS_PROFILE=tiny_plus TS_CAPTURE_DISABLED=1 python3 bench.py --tasks all --run B
Bonus: ts CLI for non-MCP agents
For agents without MCP (Cursor, Aider, Continue, scripts, CI), the ts
command exposes a subset of the tools via shell:
ts use /path/to/project
ts get my_function # JSON output
ts search 'pattern'
ts daemon start # ~145ms per call vs 1.5s cold fork
ts init --agent cursor # wire up Bash hooks for non-Claude agents
On Claude Code, prefer the MCP server -- measured cheaper than CLI on Opus 4.7. The CLI is there for the portability case.
Optional env vars
| Var | Purpose |
|---|---|
TS_BASH_COMPACT=1 |
Enable PostToolUse Bash output compactors |
TS_BASH_REWRITE=1 |
Enable PreToolUse Bash command rewriter |
TS_BASH_REWRITE_LOG |
JSONL audit log of every rewrite |
TS_COMPACT_INLINE_THRESHOLD |
Hybrid mode threshold (default 4 KB) |
TS_COMPACT_TINY_THRESHOLD |
Skip-sandbox threshold (default 256 B) |
TELEGRAM_BOT_TOKEN + TELEGRAM_CHAT_ID |
Critical-observation feed |
TS_VIEWER_PORT |
Web viewer dashboard |
TS_AUTO_EXTRACT=1 + TS_API_KEY |
LLM auto-extraction of memory observations |
TS_CAPTURE_DISABLED=1 |
Skip read-side capture sandboxing (default in optimized) |
TS_MEMORY_DISABLE=1 |
Silence memory hooks (clean-context workloads) |
License
MIT
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