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chopratejas 1601591900 feat(rust): SmartCrusher PR4 — lossless-first default + CCR-Dropped restoration
Stage 3c.2 PR4. Restores Python's CCR-Dropped semantics on the lossy
path (the cornerstone reversibility guarantee that the port had
silently dropped) and flips the OSS default to lossless-first with a
configurable savings threshold.

# The user-visible behavior

Default `SmartCrusher::new()` now runs:

  1. Try lossless compaction.
  2. If savings >= `lossless_min_savings_ratio` (default 0.30), ship
     it — `compacted` populated, `ccr_hash = None`, nothing dropped.
  3. Otherwise fall through to the lossy path — drop rows AND
     populate `ccr_hash` so the runtime can cache the full original
     for tool-call retrieval.

**No data is ever lost.** "Lossy" means "compressed view inline; full
payload retrievable via CCR cache" — same semantics as Python's
SmartCrusher with CCR enabled. The runtime (PyO3 bridge / proxy
server) owns the cache; this crate computes the hash and emits a
marker so the prompt knows where to look.

# What changed

- `SmartCrusherConfig.lossless_min_savings_ratio: f64` (default 0.30).
  Single configurable knob — Enterprise overrides as needed. Below
  the threshold, lossless declines and lossy + CCR runs.

- `SmartCrusher::new(cfg)` flips to include the compaction stage by
  default. `SmartCrusher::without_compaction(cfg)` is the explicit
  opt-out for callers / fixtures that depend on pre-PR4 behavior.

- `crush_array` rewritten:
  - Lossless-first dispatch with savings-ratio gate
  - Lossy path now hashes the full original (12-char SHA-256 prefix)
    and emits a CCR-Dropped marker in `dropped_summary` whenever
    rows are dropped
  - `ccr_hash` field populated whenever rows were dropped
  - `process_value` substitutes the compacted string into the JSON
    tree when lossless wins, so `crush()` output reflects the win

- PyO3 bridge: `SmartCrusher.without_compaction()` static method;
  `SmartCrusherConfig` exposes the new `lossless_min_savings_ratio`
  field; Python `SmartCrusher` wrapper accepts `with_compaction=True`
  (default) and routes to the right Rust constructor.

- Parity harness: legacy 17 fixtures use `without_compaction()` so
  byte-equal coverage of the lossy path is preserved.

# Tests

- Rust: 281/281 smart_crusher unit tests pass (was 277). Six new
  tests cover: lossless wins above threshold, lossy falls through
  below threshold, CCR hash deterministic + input-dependent, lossy
  without compaction emits CCR, passthrough paths don't emit CCR,
  without_compaction yields no compacted field.
- Python parity: 21/21 (legacy fixtures via without_compaction).
- Python lossless default smoke: 3/3 new tests in
  test_smart_crusher_lossless_default.py.
- Python retention: 21/21 (updated to opt into the lossy path
  explicitly since their semantics target row-level retention).
- make ci-precheck green.

Modules:
  crates/headroom-core/src/transforms/smart_crusher/{config,crusher}.rs
  crates/headroom-parity/src/lib.rs
  crates/headroom-py/src/lib.rs
  headroom/transforms/smart_crusher.py
  tests/test_quality_retention.py
  tests/test_transforms/test_smart_crusher_{lossless_default,rust_parity}.py
2026-04-27 16:30:22 -07:00
.claude-plugin feat(rust): SmartCrusher PR2 — lossless-first tabular compaction 2026-04-27 14:14:08 -07:00
.devcontainer fix: harden devcontainer worktree startup 2026-04-10 13:49:29 -05:00
.github feat(rust): SmartCrusher PR2 — lossless-first tabular compaction 2026-04-27 14:14:08 -07:00
benchmarks chore: add nosec B324 annotations to non-cryptographic MD5 usages and update temporary database path to use system temp directory 2026-04-07 13:07:26 +06:00
crates feat(rust): SmartCrusher PR4 — lossless-first default + CCR-Dropped restoration 2026-04-27 16:30:22 -07:00
docker feat(docker): forward HEADROOM_WORKSPACE_DIR and HEADROOM_CONFIG_DIR into containers 2026-04-16 19:19:25 -05:00
docs Merge remote-tracking branch 'origin/main' into rust-rewrite 2026-04-25 13:01:37 -07:00
e2e test(init): extend Docker e2e with bare/shim/per-subcommand cases 2026-04-23 16:12:27 -05:00
examples Token-level cache hit rate, compression-vs-cache tracking, dashboard SQL, security plan 2026-04-06 18:10:29 -07:00
headroom feat(rust): SmartCrusher PR4 — lossless-first default + CCR-Dropped restoration 2026-04-27 16:30:22 -07:00
plugins feat(rust): SmartCrusher PR2 — lossless-first tabular compaction 2026-04-27 14:14:08 -07:00
scripts ci: fix smart_crusher branch CI failures + add make ci-precheck pre-push gate 2026-04-27 11:13:47 -07:00
sdk/typescript chore(deps): bump the npm_and_yarn group across 3 directories with 4 updates 2026-04-24 22:15:53 +00:00
sql feat(telemetry): add headroom_stack and install_mode identity fields 2026-04-17 17:12:38 +02:00
tests feat(rust): SmartCrusher PR4 — lossless-first default + CCR-Dropped restoration 2026-04-27 16:30:22 -07:00
wiki Merge pull request #224 from gglucass/codex/compact-stats-history-default 2026-04-21 20:09:15 -07:00
.actrc feat: add act testing config, fix gitignore, make workflow production-ready 2026-04-15 20:28:29 -05:00
.actrc.local.example feat: add act testing config, fix gitignore, make workflow production-ready 2026-04-15 20:28:29 -05:00
.changelog.md fix: use /tmp for changelog artifact to avoid . file matching issues 2026-04-15 22:54:34 -05:00
.commitlintrc.json ci: fix smart_crusher branch CI failures + add make ci-precheck pre-push gate 2026-04-27 11:13:47 -07:00
.dockerignore chore: normalize line endings in init diffs 2026-04-21 20:17:14 -05:00
.env.act.example feat: add act testing config, fix gitignore, make workflow production-ready 2026-04-15 20:28:29 -05:00
.git-blame-ignore-revs chore: add .git-blame-ignore-revs 2026-04-24 15:35:29 +02:00
.gitattributes chore: enforce LF checkout for Python files 2026-04-23 08:43:03 -05:00
.gitignore ci: fix smart_crusher branch CI failures + add make ci-precheck pre-push gate 2026-04-27 11:13:47 -07:00
.pre-commit-config.yaml chore: normalize line endings in init diffs 2026-04-21 20:17:14 -05:00
Cargo.lock feat(rust): real fastembed-rs EmbeddingScorer (BAAI/bge-small-en-v1.5) 2026-04-26 23:24:59 -07:00
Cargo.toml fix(rust): smart_crusher scaffold review findings — hash truncation, int parse, python-repr matcher 2026-04-26 17:01:46 -07:00
CHANGELOG.md feat(memory): resolve Qdrant connection from HEADROOM_QDRANT_* env vars (#31) 2026-04-24 22:16:16 -07:00
CODE_OF_CONDUCT.md Prepare for OSS release v0.2.0 2026-01-07 11:36:44 -08:00
codecov.yml ci: scope codecov patch coverage 2026-04-22 00:05:47 -05:00
CONTRIBUTING.md feat: add reproducible devcontainers 2026-04-10 12:58:35 -05:00
deny.toml feat(rust): scaffold workspace + parity harness (phase-0) 2026-04-24 13:39:48 -07:00
docker-bake.hcl refactor(docker): migrate to bake with multi-variant distroless images 2026-04-04 21:51:37 +05:30
docker-compose.yml feat: add reproducible devcontainers 2026-04-10 12:58:35 -05:00
Dockerfile Add supply chain hardening: SBOM, cosign signing, pinned digests, Dependabot 2026-04-15 17:28:14 -07:00
Headroom-2.gif Add demo GIF to README 2026-01-20 18:57:17 -08:00
headroom-savings.png docs: rewrite README for clarity and highlight Kompress-base, leaderboard, RTK 2026-04-18 09:36:49 -07:00
headroom_learn.gif docs: add headroom learn demo GIF to README 2026-03-07 17:56:17 -08:00
HeadroomDemo-Fast.gif Replace demo GIF with HeadroomDemo-Fast.gif 2026-04-10 15:05:25 -07:00
LICENSE Prepare for OSS release v0.2.0 2026-01-07 11:36:44 -08:00
Makefile ci: fix smart_crusher branch CI failures + add make ci-precheck pre-push gate 2026-04-27 11:13:47 -07:00
mkdocs.yml feat: add persistent install lifecycle management 2026-04-11 13:47:05 -05:00
NOTICE Prepare for OSS release v0.2.0 2026-01-07 11:36:44 -08:00
PR.md fix: restore release and compress regressions 2026-04-18 16:01:57 -05:00
pyproject.toml feat(python): switch relevance scorer to fastembed (BAAI/bge-small-en-v1.5) 2026-04-26 23:36:22 -07:00
README.md docs: add codecov badge 2026-04-22 22:05:17 -05:00
rust-toolchain.toml fix(rust): clippy 1.95 unnecessary_sort_by + pin toolchain 2026-04-27 12:11:49 -07:00
RUST_DEV.md docs(rust): lockfile + RUST_DEV.md for proxy CLI 2026-04-25 12:49:36 -07:00
SECURITY.md Prepare for OSS release v0.2.0 2026-01-07 11:36:44 -08:00
uv.lock chore(deps): bump nltk in the uv group across 1 directory 2026-04-23 16:15:12 +00:00

Headroom

Compress everything your AI agent reads. Same answers, fraction of the tokens.

CI codecov PyPI npm Model: Kompress-base Tokens saved: 60B+ License: Apache 2.0 Docs

Headroom in action

Every tool call, log line, DB read, RAG chunk, and file your agent injects into a prompt is mostly boilerplate. Headroom strips the noise and keeps the signal — losslessly, locally, and without touching accuracy.

100 logs. One FATAL error buried at position 67. Both runs found it. Baseline 10,144 tokens → Headroom 1,260 tokens87% fewer, identical answer. python examples/needle_in_haystack_test.py


Quick start

Works with Anthropic, OpenAI, Google, Bedrock, Vertex, Azure, OpenRouter, and 100+ models via LiteLLM.

Wrap your coding agent — one command:

pip install "headroom-ai[all]"

headroom wrap claude      # Claude Code
headroom wrap codex       # Codex
headroom wrap cursor      # Cursor
headroom wrap aider       # Aider
headroom wrap copilot     # GitHub Copilot CLI

Drop it into your own code — Python or TypeScript:

from headroom import compress

result = compress(messages, model="claude-sonnet-4-5")
response = client.messages.create(model="claude-sonnet-4-5", messages=result.messages)
print(f"Saved {result.tokens_saved} tokens ({result.compression_ratio:.0%})")
import { compress } from 'headroom-ai';
const result = await compress(messages, { model: 'gpt-4o' });

Or run it as a proxy — zero code changes, any language:

headroom proxy --port 8787
ANTHROPIC_BASE_URL=http://localhost:8787 your-app
OPENAI_BASE_URL=http://localhost:8787/v1 your-app

Why Headroom

  • Accuracy-preserving. GSM8K 0.870 → 0.870 (±0.000). TruthfulQA +0.030. SQuAD v2 and BFCL both 97% accuracy after compression. Validated on public OSS benchmarks you can rerun yourself.
  • Runs on your machine. No cloud API, no data egress. Compression latency is milliseconds — faster end-to-end for Sonnet / Opus / GPT-4 class models than a hosted service round-trip.
  • Kompress-base on HuggingFace. Our open-source text compressor, fine-tuned on real agentic traces — tool outputs, logs, RAG chunks, code. Install with pip install "headroom-ai[ml]".
  • Cross-agent memory and learning. Claude Code saves a fact, Codex reads it back. headroom learn mines failed sessions and writes corrections straight to CLAUDE.md / AGENTS.md / GEMINI.md — reliability compounds over time.
  • Reversible (CCR). Compression is not deletion. The model can always call headroom_retrieve to pull the original bytes. Nothing is thrown away.

Bundles the RTK binary for shell-output rewriting — full attribution below.


How it fits

 Your agent / app
   (Claude Code, Cursor, Codex, LangChain, Agno, Strands, your own code…)
        │   prompts · tool outputs · logs · RAG results · files
        ▼
    ┌────────────────────────────────────────────────────┐
    │  Headroom   (runs locally — your data stays here)  │
    │  ───────────────────────────────────────────────   │
    │  CacheAligner  →  ContentRouter  →  CCR             │
    │                    ├─ SmartCrusher   (JSON)         │
    │                    ├─ CodeCompressor (AST)          │
    │                    └─ Kompress-base  (text, HF)     │
    │                                                     │
    │  Cross-agent memory  ·  headroom learn  ·  MCP      │
    └────────────────────────────────────────────────────┘
        │   compressed prompt  +  retrieval tool
        ▼
 LLM provider  (Anthropic · OpenAI · Bedrock · …)

Architecture · CCR reversible compression · Kompress-base model card

Canonical pipeline lifecycle

Headroom now exposes one stable request lifecycle across compress(), the SDK, and the proxy:

SetupPre-StartPost-StartInput ReceivedInput CachedInput RoutedInput CompressedInput RememberedPre-SendPost-SendResponse Received

  • Transforms still do the work: CacheAligner, ContentRouter, SmartCrusher, CodeCompressor, Kompress-base, IntelligentContext / RollingWindow.
  • Pipeline extensions observe or customize those lifecycle stages via on_pipeline_event(...).
  • Compression hooks still work and now sit alongside the canonical lifecycle instead of being the only extension seam.
  • Proxy extensions remain the server/app integration seam for ASGI middleware, routes, and startup policy.

Provider slices

Provider and tool-specific behavior is being moved behind dedicated modules under headroom/providers/ so core orchestration stays focused on lifecycle, sequencing, and policy.

  • CLI/tool slices: headroom/providers/claude, copilot, codex, openclaw
  • Provider runtime slices: headroom/providers/claude, gemini, plus shared backend/runtime dispatch in headroom/providers/registry.py
  • Core files stay orchestration-first: wrap.py, client.py, cli/proxy.py, and proxy/server.py now delegate provider-specific env shaping, API target normalization, backend selection, and transport dispatch instead of inlining those rules.

Proof

Savings on real agent workloads:

Workload Before After Savings
Code search (100 results) 17,765 1,408 92%
SRE incident debugging 65,694 5,118 92%
GitHub issue triage 54,174 14,761 73%
Codebase exploration 78,502 41,254 47%

Accuracy preserved on standard benchmarks:

Benchmark Category N Baseline Headroom Delta
GSM8K Math 100 0.870 0.870 ±0.000
TruthfulQA Factual 100 0.530 0.560 +0.030
SQuAD v2 QA 100 97% 19% compression
BFCL Tools 100 97% 32% compression

Reproduce:

python -m headroom.evals suite --tier 1

Community, live:

Full benchmarks & methodology


Built for coding agents

Agent One-command wrap Notes
Claude Code headroom wrap claude --memory for cross-agent memory, --code-graph for codebase intel
Codex headroom wrap codex --memory Shares the same memory store as Claude
Cursor headroom wrap cursor Prints Cursor config — paste once, done
Aider headroom wrap aider Starts proxy, launches Aider
Copilot CLI headroom wrap copilot Starts proxy, launches Copilot
OpenClaw headroom wrap openclaw Installs Headroom as ContextEngine plugin

MCP-native too — headroom mcp install exposes headroom_compress, headroom_retrieve, and headroom_stats to any MCP client.

headroom learn in action

Integrations

Drop Headroom into any stack
Your setup Hook in with
Any Python app compress(messages, model=…)
Any TypeScript app await compress(messages, { model })
Anthropic / OpenAI SDK withHeadroom(new Anthropic()) · withHeadroom(new OpenAI())
Vercel AI SDK wrapLanguageModel({ model, middleware: headroomMiddleware() })
LiteLLM litellm.callbacks = [HeadroomCallback()]
LangChain HeadroomChatModel(your_llm)
Agno HeadroomAgnoModel(your_model)
Strands Strands guide
ASGI apps app.add_middleware(CompressionMiddleware)
Multi-agent SharedContext().put / .get
MCP clients headroom mcp install
What's inside
  • SmartCrusher — universal JSON: arrays of dicts, nested objects, mixed types.
  • CodeCompressor — AST-aware for Python, JS, Go, Rust, Java, C++.
  • Kompress-base — our HuggingFace model, trained on agentic traces.
  • Image compression — 4090% reduction via trained ML router.
  • CacheAligner — stabilizes prefixes so Anthropic/OpenAI KV caches actually hit.
  • IntelligentContext — score-based context fitting with learned importance.
  • CCR — reversible compression; LLM retrieves originals on demand.
  • Cross-agent memory — shared store, agent provenance, auto-dedup.
  • SharedContext — compressed context passing across multi-agent workflows.
  • headroom learn — plugin-based failure mining for Claude, Codex, Gemini.

Install

pip install "headroom-ai[all]"          # Python, everything
npm  install headroom-ai                # TypeScript / Node
docker pull ghcr.io/chopratejas/headroom:latest

Granular extras: [proxy], [mcp], [ml] (Kompress-base), [agno], [langchain], [evals]. Requires Python 3.10+.

Installation guide — Docker tags, persistent service, PowerShell, devcontainers.


Documentation

Start here Go deeper
Quickstart Architecture
Proxy How compression works
MCP tools CCR — reversible compression
Memory Cache optimization
Failure learning Benchmarks
Configuration Limitations

Compared to

Headroom runs locally, covers every content type (not just CLI or text), works with every major framework, and is reversible.

Scope Deploy Local Reversible
Headroom All context — tools, RAG, logs, files, history Proxy · library · middleware · MCP Yes Yes
RTK CLI command outputs CLI wrapper Yes No
Compresr, Token Co. Text sent to their API Hosted API call No No
OpenAI Compaction Conversation history Provider-native No No

Attribution. Headroom ships with the excellent RTK binary for shell-output rewriting — git showgit show --short, noisy ls → scoped, chatty installers → summarized. Huge thanks to the RTK team; their tool is a first-class part of our stack, and Headroom compresses everything downstream of it.


Contributing

git clone https://github.com/chopratejas/headroom.git && cd headroom
pip install -e ".[dev]" && pytest

Devcontainers in .devcontainer/ (default + memory-stack with Qdrant & Neo4j). See CONTRIBUTING.md.


Community

License

Apache 2.0 — see LICENSE.