Mirror of headroomlabs-ai/headroom (AI context compression proxy)
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chopratejas 8b3adeadd7 fix(rust): proxy token-mode — freeze prefix, compress new-turn tool outputs only
Replaces the ICM-based interceptor on /v1/messages and adds OpenAI
/v1/chat/completions and /v1/responses arms. The proxy now follows
exactly one rule, applied per-request:

  Find the last user message. Freeze every byte before it. In the
  new turn, walk for tool outputs and route them through the
  CompressionPipeline (Diff/Log/Json offloads + JsonMinifier/
  LogTemplate reformats). Everything else passes through.

Why this design:
  - Provider prefix caches (Anthropic cache_control, OpenAI auto
    prefix, OpenAI prompt_cache_key) are positional. We never modify
    prefix bytes, so cache hits are preserved 100%.
  - User text, system prompts, assistant text are never touched —
    accuracy preserved.
  - Tool outputs (file reads, search results, build logs, diffs)
    are where the tokens are. The CompressionPipeline already in
    headroom-core compresses them with CCR backup.

What this PR removes:
  - ICM (IntelligentContextManager) is no longer wired into the
    proxy. It's still in headroom-core for future use, but the
    proxy crate doesn't import it. ICM message-dropping risks
    cache busts that token mode rules out by construction.

What this PR adds (compression module rewrite):
  - compression/walker.rs   — compress_blob() shared helper
  - compression/pipeline.rs — build CompressionPipeline + CcrStore
                              once at startup
  - compression/anthropic.rs — token-mode walker (tool_result blocks)
  - compression/openai.rs    — token-mode walker (role:tool messages)
  - compression/responses.rs — token-mode walker (function_call_output
                              items; previous_response_id skips)
  - compression/mod.rs       — endpoint classifier + dispatch

Per-shape rules documented per file. Highlights:
  - Anthropic: walk tool_result blocks (string OR list); compress
    text inside list-shaped blocks; preserve images
  - OpenAI chat: only role:tool with string content
  - OpenAI responses: only function_call_output with string output;
    reasoning items, *_call items, image_generation_call all
    preserved verbatim; previous_response_id triggers full
    passthrough (server holds the conversation)

Tests:
  - Unit (32 in compression module + 3 walker tests)
  - Mock integration (8 tests, including prefix-byte-identical
    assertion across Anthropic / OpenAI / Responses)
  - Real OpenAI e2e (3 tests, gated on HEADROOM_E2E=1):
      * /v1/chat/completions tool message: 70 prompt tokens received
        (compressed from a ~120KB / ~30K-token raw log payload)
      * /v1/responses function_call_output: 68 input tokens
        (same payload, same compression)
      * Prefix cache preservation: 3,456 of 3,518 tokens cached
        on the second turn (98%) — proves byte-stable prefix

Verification:
  - cargo test --workspace -> 904 passed, 0 failed
  - cargo clippy --workspace --all-targets -- -D warnings -> clean
  - cargo fmt --check -> clean
  - HEADROOM_E2E=1 cargo test --test e2e_token_mode -> 3/3 pass
  - make ci-precheck -> green
2026-05-01 21:31:35 -07:00
.claude-plugin fix(rust): proxy token-mode — freeze prefix, compress new-turn tool outputs only 2026-05-01 21:31:35 -07:00
.devcontainer fix: harden devcontainer worktree startup 2026-04-10 13:49:29 -05:00
.github fix(rust): proxy token-mode — freeze prefix, compress new-turn tool outputs only 2026-05-01 21:31:35 -07:00
benchmarks chore(transforms): retire dead text_compressor module (Phase 3e.3) 2026-04-29 21:14:36 -07:00
crates fix(rust): proxy token-mode — freeze prefix, compress new-turn tool outputs only 2026-05-01 21:31:35 -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 fix(proxy): cache concurrency lock, multi-worker docs, bounded compression executor 2026-05-01 15:25:18 -07:00
plugins fix(rust): proxy token-mode — freeze prefix, compress new-turn tool outputs only 2026-05-01 21:31:35 -07:00
scripts fix(rust): wire ICM compressor into Rust proxy on /v1/messages 2026-05-01 16:44:44 -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 fix(test): stub _run_compression_in_executor on _DummyOpenAIHandler 2026-05-01 16:53:21 -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 fix(rust): wire ICM compressor into Rust proxy on /v1/messages 2026-05-01 16:44:44 -07:00
.pre-commit-config.yaml chore: normalize line endings in init diffs 2026-04-21 20:17:14 -05:00
Cargo.lock fix(rust): audit cleanup — DiffCompressor CCR leak, CCR TOCTOU race, clippy debt, dep dedup 2026-04-30 20:54:22 -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 chore(traffic-learner): apply ruff format + add CHANGELOG entry 2026-04-30 17:47:10 +09:00
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 fix(proxy): cache concurrency lock, multi-worker docs, bounded compression executor 2026-05-01 15:25:18 -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.