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chopratejas 79baee082f fix(content-router,proxy): cache-safe text-block compression and online streaming usage
PR #431 (merged) added text-block compression to support DeepSeek + Cline,
but the gate ("skip user/system") leaves assistant text blocks compressible
by default. Assistant content is echoed back by the client in subsequent
turns and becomes part of the upstream provider's prefix cache (Anthropic
explicit cache_control, DeepSeek/OpenAI auto-prefix). Compressing it
silently changes the bytes the next turn must match for a cache hit —
turning a 90% read discount into a 25% write penalty on Anthropic, or a
full prefill on DeepSeek/OpenAI when the in-process result cache evicts
or differs across restarts.

Re-aligns the design around prefix-cache safety:

  * Block-level cache_control protection (defense in depth). Any block
    carrying cache_control is the client's explicit cache breakpoint;
    never modified, regardless of role or block type. Closes the gap
    that frozen_message_count alone leaves — that count is a coarse
    message-level approximation; this is the per-block guarantee.
    Applies to both tool_result and text paths.

  * compress_assistant_text_blocks defaults to False (off). Assistant
    text blocks are skipped by default, restoring pre-#431 cache safety
    for Anthropic flows. Per-request opt-in via kwargs (or via
    ContentRouterConfig.compress_assistant_text_blocks for deployment-
    wide enable) preserves the Cline + DeepSeek goal — only enable
    when the backend doesn't honor cache_control AND compression is
    deterministic enough that the auto-prefix cache still hits across
    eviction/restart.

  * Unknown roles default-skip too (was: compressed). developer/judge/
    custom roles are safer to leave untouched than to compress
    aggressively without thinking through their cache semantics.

  * Online streaming usage parser. Replaces the per-stream
    list[bytes] buffer with a single last_completion_tokens int updated
    per chunk via a module-level _parse_completion_tokens_from_sse_chunk
    helper. Streaming memory is now O(1) regardless of stream length —
    important for 200K-output reasoning models and DeepSeek V4 Pro's
    384K max output.

  * Renames the unused min_tokens parameter to min_chars (the threshold
    has always been chars, not tokens, in both the tool_result and text
    paths). Now also wired through ContentRouterConfig
    .min_chars_for_block_compression so the threshold is configurable
    per Realignment build constraints.

Tests:
  * 17 new tests in tests/test_transforms_content_router.py covering
    the role matrix (user / system / assistant / tool / unknown),
    cache_control protection on both paths, opt-in semantics, the
    min_chars threshold, and idempotent pinning detection.
  * 9 new tests in tests/test_streaming_usage_parser.py covering the
    online parser's success and edge cases (usage frame, [DONE],
    invalid JSON, multi-frame chunks, zero tokens, non-dict payloads,
    invalid UTF-8).

Trade-off: deployments pointed at non-cache-aware backends (DeepSeek
direct, OpenAI direct) lose blanket assistant-text compression by
default — they opt in via config. Anthropic flows go back to being
prefix-cache-safe out of the box.
2026-05-08 15:20:54 -07:00
.claude-plugin fix: add Codex wire debug and WS usage metrics 2026-05-08 13:53:52 -07:00
.devcontainer fix(ci): rustls-everywhere — eliminate openssl-sys from build tree 2026-05-03 23:26:04 -07:00
.github fix: add Codex wire debug and WS usage metrics 2026-05-08 13:53:52 -07:00
benchmarks fix: B2 — live-zone block dispatcher skeleton 2026-05-02 12:45:43 -07:00
crates Merge pull request #427 from mbachaud/fix/vertex-dead-code-and-body-limit 2026-05-08 10:24:12 -07:00
docker feat(docker): forward HEADROOM_WORKSPACE_DIR and HEADROOM_CONFIG_DIR into containers 2026-04-16 19:19:25 -05:00
docs fix: harden release gating and clarify pipx compatibility 2026-05-06 12:41:17 +02:00
e2e style(ci): apply ruff format to bug-3 fix files 2026-05-06 12:23:10 -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(content-router,proxy): cache-safe text-block compression and online streaming usage 2026-05-08 15:20:54 -07:00
plugins fix: add Codex wire debug and WS usage metrics 2026-05-08 13:53:52 -07:00
REALIGNMENT docs: add Realignment plan (40 PRs, 9 phases) 2026-05-01 23:34:46 -07:00
scripts fix(crusher): shim __libc_single_threaded for glibc < 2.32 + extend audit 2026-05-05 13:59:21 -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(content-router,proxy): cache-safe text-block compression and online streaming usage 2026-05-08 15:20:54 -07:00
wiki Merge pull request #411 from manorit2001/wip 2026-05-08 10:24:22 -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
.gitguardian.yaml fix(security): allowlist GitGuardian-flagged test fixtures 2026-05-02 18:33:22 -07:00
.gitignore fix: ship glibc 2.38 compat shim + wheel symbol audit (closes #355) 2026-05-04 21:31:19 -07:00
.pre-commit-config.yaml chore: normalize line endings in init diffs 2026-04-21 20:17:14 -05:00
Cargo.lock fix: PR-E1 tool array deterministic sort (Phase E) 2026-05-05 15:35:27 -07:00
Cargo.toml fix(proxy): PR-D4 native Vertex publisher path + ADC bearer auth 2026-05-04 16:24:38 -07:00
CHANGELOG.md fix: harden release gating and clarify pipx compatibility 2026-05-06 12:41:17 +02:00
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 fix(ci): rustls-everywhere — eliminate openssl-sys from build tree 2026-05-03 23:26:04 -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 fix: A0 — fail-loud rust core deployment smoke test 2026-05-02 17:52:37 -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 Merge pull request #422 from chopratejas/fix-user-experience-and-feature-clarity 2026-05-07 16:46:55 -07:00
README.md fix: harden release gating and clarify pipx compatibility 2026-05-06 12:41:17 +02:00
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: B7 — CCR hardening: persistent backends + always-on tool 2026-05-02 16:52:33 -07:00
SECURITY.md Prepare for OSS release v0.2.0 2026-01-07 11:36:44 -08:00
uv.lock fix(ci): pin public PyPI in pyproject.toml + scrub Netflix URLs from uv.lock 2026-05-03 13:52:16 -07:00

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

Using pipx? Current release wheels are built for Python 3.10 through 3.13, so choose a supported interpreter explicitly:

pipx install --python python3.13 "headroom-ai[all]"

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.