headroom/wiki/integration-guide.md
Tejas Chopra e0ce4b1d48
fix: remove rtk and lean-ctx CLI context tools (#2677)
## Description

Removes both third-party CLI context tools — **rtk** and **lean-ctx** —
and with them the context-tool selector itself. Headroom no longer
downloads, installs or configures either one, and there is no
replacement.

The previous pass (#2344) gated only three entry points inside
`headroom/cli/wrap.py`. That left the feature reachable in practice:

| Gap | Effect |
|---|---|
| `scripts/install.sh:1544`, `install.ps1:1681` | Ran `rtk init --global
--auto-patch` from bash/PowerShell, **bypassing the Python gate
entirely** — `curl \| sh` still wrote a Claude Code `PreToolUse` hook
regardless of `HEADROOM_RTK` |
| `wrap.py` `_setup_context_tool_for_agent` | **`wrap openhands` was
broken by default**: `rtk_required=True` met a gate returning `None` →
`SystemExit(1)`. Invisible because all 8 openhands tests patched
`_ensure_rtk_binary` to a fake path |
| `proxy/helpers.py`, `subscription/tracker.py` | Proxy shelled out to
`rtk gain` from `/stats`, the dashboard and `headroom perf`; the tracker
polled it per contribution (`_RTK_WIRING_DEFAULT = "enabled"`) |
| No cleanup path | Nothing removed artifacts an earlier default had
installed, so a machine that once ran the old default kept rtk in the
loop forever (#1669, #1955) |

Also worth noting: the rtk binary download had **no SHA or signature
verification** — only `rtk --version` as a smoke test.

## Type of Change

- [x] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Performance improvement
- [x] Code refactoring (no functional changes)

## Changes Made

**Removed** — `headroom/rtk/` and `headroom/lean_ctx/` packages,
`headroom/cli/wrap_rtk_metrics.py`, `_selected_context_tool` /
`_setup_context_tool_for_agent` / `_VALID_CONTEXT_TOOLS`, the `--rtk` /
`--no-rtk` / `--no-project-rtk` / `--keep-rtk` flags across all 18 wrap
subcommands, `HEADROOM_RTK*`, the proxy-side `rtk gain` polling, the
dashboard CLI-filtering panel (rows + all 8 `cliFiltering*` Alpine
getters), `paths.rtk_path()` / `lean_ctx_path()`, the SDK path helpers,
`benchmarks/rtk_loop_learn_eval.py`, and the `headroom/rtk/**` CI path
filters.

**Fails loudly, not silently** — `--context-tool` / `--no-context-tool`
/ `HEADROOM_CONTEXT_TOOL` are kept solely to error out. They live in
shell profiles, aliases and CI jobs, and accepting them as a no-op would
read as Headroom having quietly stopped working. The installers reject
them too, which matters more than it looks: their arg parsers forward
the first unknown flag **and everything after it** to the wrapped tool,
so a leftover `--no-rtk` would have silently swallowed a following
`--port` and then been ignored downstream.

**New `headroom/context_tool_cleanup.py`** — deleting the code cannot
help a machine that already ran the old default, since the hooks,
binaries and injected guidance are durable on disk.
`purge_context_tool_artifacts()` runs once per `wrap`/`unwrap` and
removes the registered hook entries, the generated hook scripts, the
Headroom-managed `~/.local/bin` symlinks, the vendored
`~/.headroom/bin/{rtk,lean-ctx}` binaries, the `lean-ctx` MCP server
entry and the marker-fenced instruction blocks. Deliberately
conservative: idempotent, **skips** a malformed config rather than
overwriting it, and only unlinks a symlink resolving inside Headroom's
own bin dir so a user's own build is untouched. It reports on
**stderr**, because `wrap/unwrap openclaw --prepare-only` emit
machine-readable JSON on stdout as their entire contract. Skipped for
`wrap selfheal` (runs from a SessionStart hook; must not race Claude
Code's writer for `~/.claude.json`) and for `--help`, which must stay
read-only.

**Client-config hardening** (discovered while investigating a "corrupted
Serena settings file" report) — `wrap.py` reset a settings file to `{}`
when an existing file would not parse, then wrote that back. One
hand-edited typo or a transient `EACCES`/`EINTR` on a valid file
destroyed the user's `permissions`, `env` and `hooks`, on **every
`headroom wrap claude`**. It now refuses to write. Separately,
`fsutil.write_text` is now atomic (temp file + `fsync` + `os.replace`),
fixing all 14 non-atomic client-config writes at once; it follows
symlinks rather than replacing them (dotfile managers) and preserves an
existing file's mode.

**Deliberately kept** — `rtk` stays in the wrapper-peel list in
`transforms/content_router.py`. It sits beside `sudo`/`env`/`timeout` as
shell-command grammar, so `rtk cat f` is still classified as a file read
for anyone running their own rtk install, which the purge intentionally
leaves alone.

## Testing

- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [x] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [x] Manual testing performed

### Test Output

```text
$ ruff check headroom/ tests/ e2e/ --exclude headroom/dashboard/templates
All checks passed!

$ ruff format --check headroom/ tests/ e2e/ --exclude headroom/dashboard/templates
1255 files already formatted

$ mypy headroom/
Success: no issues found in 508 source files

$ pytest tests/test_context_tool_cleanup.py -q
11 passed

$ pytest tests/test_fsutil.py -q
12 passed

$ pytest tests/test_cli/test_wrap_codex.py -q            # 89 tests
89 passed in 431.68s
$ pytest tests/test_cli/test_wrap_opencode.py -q
39 passed in 257.46s
$ pytest tests/test_cli/test_wrap_helpers.py -q
45 passed
$ pytest tests/test_paths.py -q
75 passed
$ pytest tests/test_cli/test_unwrap_claude.py -q
14 passed
$ pytest tests/test_proxy_savings_history.py -q
39 passed
$ pytest tests/test_cli/test_wrap_copilot.py -q
27 passed
$ pytest tests/test_cli/test_wrap_zcode.py -q
20 passed
$ pytest tests/test_subscription_tracker.py -q
9 passed
$ pytest tests/test_proxy_dashboard_stats_cache.py -q
5 passed, 1 skipped
```

Repo-wide grep for 14 removed symbols (`headroom.rtk`,
`headroom.lean_ctx`, `_ensure_rtk_binary`, `_selected_context_tool`,
`_get_context_tool_stats`, `rtk_path`, `lean_ctx_path`,
`wrap_rtk_metrics`, `HEADROOM_RTK`, `cli_tokens_avoided`,
`tokens_saved_rtk`, …) across `*.py`, `*.ts`, `*.sh`, `*.ps1`, `*.yml`,
`*.html`: **zero hits**.

Notable test changes: `test_wrap_openhands.py` no longer patches
`_ensure_rtk_binary` and asserts `wrap openhands --prepare-only` exits 0
unpatched — the regression that was previously masked.
`test_wrap_continue.py` and `test_wrap_hintfile_agents.py` were removed
(every test drove RTK instruction injection). A new
`test_subscription_tracker.py::test_load_state_written_before_cli_context_tools_were_removed`
proves a pre-removal `subscription_state.json` still loads.

## Real Behavior Proof

- **Environment:** macOS 15.4 (darwin 25.4.0), Python 3.12.6, Headroom @
this branch, real `~/.headroom` and `~/.claude` on the dev machine.
- **Exact command / steps and observed result:**

```text
# 1. Retired flag fails loudly instead of silently no-op'ing
$ headroom wrap codex --prepare-only --context-tool rtk
Error: CLI context tools (rtk, lean-ctx) have been removed from Headroom: they
rewrote shell commands through a third-party binary Headroom no longer manages.
Drop --context-tool / --no-context-tool and unset HEADROOM_CONTEXT_TOOL;
`headroom wrap` uninstalls what they left behind on first run.

$ HEADROOM_CONTEXT_TOOL=lean-ctx headroom wrap codex --prepare-only
Error: CLI context tools (rtk, lean-ctx) have been removed from Headroom: ...

# 2. install.sh rejects the retired flags (extracted parse_wrap_args harness)
['--no-rtk', '--port', '9999']   rc=1  ERROR: CLI context tools ... Drop --no-rtk
['--context-tool=rtk']           rc=1  ERROR: CLI context tools ... Drop --context-tool
$ bash -n scripts/install.sh   # syntax OK

# 3. Purge ran against the real machine, which had all the orphaned artifacts
$ python -c "from headroom.context_tool_cleanup import purge_context_tool_artifacts; ..."
  removed ~/.headroom/bin/lean-ctx        (51 MB)
  removed ~/.headroom/bin/rtk             (7.7 MB)
  removed ~/.local/bin/rtk                (symlink into ~/.headroom/bin)
  removed ~/.claude/hooks/rtk-rewrite.sh
  removed 8 lean-ctx-* hook scripts
# ~/.claude.json afterwards: 90 top-level keys, 19 projects, mcpServers unchanged
# → ~59 MB reclaimed, no unrelated key touched

# 4. stdout stays machine-readable while the purge reports (planted a fake artifact)
$ headroom wrap openclaw --prepare-only --gateway-provider-id codex >out 2>err
$ cat out
{"enabled":true,"config":{"proxyPort":8787,...}}     # parses as JSON
$ cat err
Retired CLI context tool cleanup: removed /Users/tcms/.headroom/bin/rtk

# 5. --help is inert (planted artifact survives), a real run purges
$ headroom wrap codex --help   → artifact survived: CORRECT
$ headroom wrap openclaw --prepare-only → purged: CORRECT

# 6. MCP purge dry-run against a copy of the real 82 KB ~/.claude.json
top-level keys 90 -> 90;  projects 19 -> 19;  LOST keys: none
all content outside mcpServers byte-identical: True
```

Dashboard rendered via the Playwright test after the panel removal:
"Token Savings" shows only `Proxy 0 (0.0%)` / `Of total wire: 36.86%`,
and "Token Usage" reads Before Compression → Proxy Removed → After
Compression with no "Filtered (this session)" row. Nothing below the
removed panel broke.

- **Not tested:** Windows and Linux (macOS only) — `install.ps1` is
verified by brace-balance and inspection, not executed, since no `pwsh`
is available locally. The wrap e2e suite (`e2e/wrap/run.py`) was updated
but not run; it needs the Docker e2e image. `serena project index`
interaction is exercised in the stacked base PR.

## Review Readiness

- [x] I have performed a self-review
- [x] This PR is ready for human review

## Checklist

- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] I did **not** edit `CHANGELOG.md` — it is generated by
release-please from my Conventional Commit PR title (a CI guard enforces
this)

## Additional Notes

**Stacked on #2676** (`tejas/serena-config-bootstrap`) — please merge
that first; this PR's base should then be retargeted to `main`, or it
will read as containing that fix too.

**Breaking-change migration for users:**
- Drop `--rtk`, `--no-rtk`, `--no-project-rtk`, `--keep-rtk`,
`--context-tool`, `--no-context-tool` from any alias, script or CI job,
and unset `HEADROOM_RTK*` / `HEADROOM_CONTEXT_TOOL`. They now error
rather than being ignored, so the failure is immediate and
self-explaining.
- Previously-installed artifacts are purged automatically on the next
`wrap`/`unwrap`; no manual cleanup needed.
- `headroom perf --json` no longer carries a `cli_filtering` key, and
`/stats` no longer returns a `context_tool` section.

**Docs:** `docs/rtk-architecture.md` deleted; RTK/lean-ctx removed from
`README.md`,
`docs/content/docs/{configuration,opencode,grok-build,docker-install,filesystem-contract}.mdx`,
`docs/observability.md` and the matching `wiki/` pages.
`REALIGNMENT/09-phase-G-rtk-observability.md` is marked SUPERSEDED
rather than deleted, to keep the planning record.

**Follow-ups not in scope:** `_emit_wrap_interrupted` was deleted as
dead code — its only caller was the `except KeyboardInterrupt` guarding
the binary download, so with no download there is nothing slow left to
interrupt.
2026-07-30 22:59:41 -07:00

10 KiB

Integration Guide

You don't need to run the Headroom proxy. Headroom is a compression library that works with any LLM client, proxy, or framework.

Pick Your Path

You have... Use this Setup
Any Python app compress() 2 lines
LiteLLM LiteLLM callback 1 line
A Python proxy (FastAPI, custom) ASGI middleware 1 line
Claude Code / Cursor / Copilot CLI Headroom proxy 1 command or env var
Agno agents Agno integration Wrap model
LangChain LangChain integration Wrap model
Non-Python app Headroom proxy HTTP
TypeScript SDK compress() npm install headroom-ai
Vercel AI SDK headroomMiddleware() Middleware adapter
OpenAI Node SDK withHeadroom() Client wrapper
Anthropic TS SDK withHeadroom() Client wrapper

compress() Function

The simplest integration. Works with any LLM client.

from headroom import compress

# Before sending to your LLM:
result = compress(messages, model="claude-sonnet-4-5-20250929")
response = your_client.create(messages=result.messages)  # Fewer tokens, same answer

print(f"Saved {result.tokens_saved} tokens ({result.compression_ratio:.0%})")

With Anthropic SDK

from anthropic import Anthropic
from headroom import compress

client = Anthropic()
messages = [
    {"role": "user", "content": "What went wrong?"},
    {"role": "assistant", "content": "Let me check.", "tool_use": [...]},
    {"role": "user", "content": [{"type": "tool_result", "content": huge_json}]},
]

compressed = compress(messages, model="claude-sonnet-4-5-20250929")
response = client.messages.create(
    model="claude-sonnet-4-5-20250929",
    messages=compressed.messages,
    max_tokens=1000,
)

With OpenAI SDK

from openai import OpenAI
from headroom import compress

client = OpenAI()
messages = [
    {"role": "user", "content": "Analyze these results"},
    {"role": "tool", "content": big_json_output, "tool_call_id": "call_1"},
]

compressed = compress(messages, model="gpt-4o")
response = client.chat.completions.create(
    model="gpt-4o",
    messages=compressed.messages,
)

With LiteLLM (direct)

import litellm
from headroom import compress

messages = [...]
compressed = compress(messages, model="bedrock/claude-sonnet")
response = litellm.completion(model="bedrock/claude-sonnet", messages=compressed.messages)

With any HTTP client

import httpx
from headroom import compress

compressed = compress(messages, model="claude-sonnet-4-5-20250929")
httpx.post("https://api.anthropic.com/v1/messages", json={
    "model": "claude-sonnet-4-5-20250929",
    "messages": compressed.messages,
}, headers={"X-Api-Key": api_key, "anthropic-version": "2023-06-01"})

What compress() returns

result = compress(messages, model="gpt-4o")
result.messages           # list[dict] — compressed messages, same format as input
result.tokens_before      # int — original token count
result.tokens_after       # int — compressed token count
result.tokens_saved       # int — tokens removed
result.compression_ratio  # float — 0.0 (no savings) to 1.0 (100% removed)
result.transforms_applied # list[str] — what ran (e.g., ["router:smart_crusher:0.35"])

LiteLLM

If you're already using LiteLLM as your LLM gateway, add Headroom as a callback:

import litellm
from headroom.integrations.litellm_callback import HeadroomCallback

litellm.callbacks = [HeadroomCallback()]

# All calls now compressed automatically
response = litellm.completion(model="gpt-4o", messages=[...])
response = litellm.completion(model="bedrock/claude-sonnet", messages=[...])
response = litellm.completion(model="azure/gpt-4o", messages=[...])

The callback compresses messages in LiteLLM's pre_call_hook before they're sent to the provider. Works with all 100+ LiteLLM-supported providers.

With LiteLLM Proxy

If you run LiteLLM as a proxy server, use the ASGI middleware instead:

# In your LiteLLM proxy startup
from litellm.proxy.proxy_server import app
from headroom.integrations.asgi import CompressionMiddleware

app.add_middleware(CompressionMiddleware)

Or use the callback in your LiteLLM config:

# litellm_config.yaml
litellm_settings:
  callbacks: ["headroom.integrations.litellm_callback.HeadroomCallback"]

ASGI Middleware

Drop-in middleware for any ASGI application (FastAPI, Starlette, LiteLLM proxy, custom proxies).

from headroom.integrations.asgi import CompressionMiddleware

# FastAPI
app = FastAPI()
app.add_middleware(CompressionMiddleware)

# Starlette
app = Starlette(routes=[...])
app.add_middleware(CompressionMiddleware)

# LiteLLM proxy
from litellm.proxy.proxy_server import app
app.add_middleware(CompressionMiddleware)

The middleware intercepts POST requests to /v1/messages, /v1/chat/completions, /v1/responses, and /chat/completions. All other requests pass through untouched.

Response headers include:

  • x-headroom-compressed: true — compression was applied
  • x-headroom-tokens-saved: 1234 — tokens removed

Proxy

The Headroom proxy is a standalone HTTP server. Best for non-Python apps or tools that only support base URL configuration (Claude Code, Cursor, GitHub Copilot CLI).

pip install "headroom-ai[all]"
headroom proxy --port 8787
# Claude Code
ANTHROPIC_BASE_URL=http://localhost:8787 claude

# GitHub Copilot CLI
headroom wrap copilot -- --model claude-sonnet-4-20250514

# Cursor / Any OpenAI client
OPENAI_BASE_URL=http://localhost:8787/v1 cursor

For translated backends, the Copilot wrapper can switch to Headroom's OpenAI-compatible route:

headroom wrap copilot --backend anyllm --anyllm-provider groq -- --model gpt-4o

For Copilot's hosted API (--subscription and the implicit OAuth path), Headroom routes to the generic host https://api.githubcopilot.com, which serves the full model set. Enterprise / data-residency tenants on a dedicated Copilot host pin it with GITHUB_COPILOT_API_URL (e.g. export GITHUB_COPILOT_API_URL=https://api.<your-host>.githubcopilot.com); the override flows through to the upstream request. See TESTING-copilot-subscription.md.

With Cloud Providers

# AWS Bedrock
headroom proxy --backend bedrock --region us-east-1

# Google Vertex AI
headroom proxy --backend vertex_ai --region us-central1

# Azure OpenAI
headroom proxy --backend azure

# OpenRouter (400+ models)
OPENROUTER_API_KEY=sk-or-... headroom proxy --backend openrouter

See Proxy Documentation for all options.


Agno

Full integration with the Agno agent framework.

from agno.agent import Agent
from agno.models.anthropic import Claude
from headroom.integrations.agno import HeadroomAgnoModel

model = HeadroomAgnoModel(Claude(id="claude-sonnet-4-20250514"))
agent = Agent(model=model, tools=[your_tools])
response = agent.run("Investigate the issue")

print(f"Tokens saved: {model.total_tokens_saved}")

See Agno Guide for hooks, multi-provider, and streaming.


LangChain

Full integration with LangChain — chat models, memory, retrievers, tool wrappers, and streaming.

from langchain_openai import ChatOpenAI
from headroom.integrations import HeadroomChatModel

llm = HeadroomChatModel(ChatOpenAI(model="gpt-4o"))
response = llm.invoke("Hello!")

See LangChain Guide for details and known limitations.


TypeScript SDK

For Node.js, Next.js, and any TypeScript/JavaScript application.

npm install headroom-ai

See the TypeScript SDK Guide for full documentation including Vercel AI SDK middleware, OpenAI SDK wrapper, and Anthropic SDK wrapper.


OpenClaw

Context compression plugin for OpenClaw agents.

headroom wrap openclaw

Configure as context engine:

{ "plugins": { "slots": { "contextEngine": "headroom" } } }

Manual install remains available when you are not using the CLI wrapper:

pip install "headroom-ai[proxy]"
openclaw plugins install --dangerously-force-unsafe-install headroom-ai/openclaw

The plugin auto-detects a running Headroom proxy or starts one. Compression happens in assemble() — zero changes to the agent's behavior.

See the OpenClaw plugin documentation for full setup.


Compression Hooks (Advanced)

Customize compression behavior without modifying Headroom's code:

from headroom import compress, CompressionHooks, CompressContext

class MyHooks(CompressionHooks):
    def pre_compress(self, messages, ctx):
        # Modify messages before compression (dedup, filter, inject)
        return messages

    def compute_biases(self, messages, ctx):
        # Per-message compression aggressiveness
        # >1.0 = keep more, <1.0 = compress more
        return {5: 1.5, 6: 0.5}  # Keep message 5, compress message 6

    def post_compress(self, event):
        # Observe results (logging, analytics, learning)
        print(f"Saved {event.tokens_saved} tokens")

result = compress(messages, model="gpt-4o", hooks=MyHooks())

See Architecture for how hooks integrate with the pipeline.


FAQ

Q: Does Headroom change the response format? No. Your LLM returns the same response format. Headroom only modifies the input messages.

Q: What if compression removes something the LLM needs? Headroom stores originals in CCR (Compress-Cache-Retrieve). The LLM can call headroom_retrieve to get full uncompressed content. Compression summaries tell the LLM what's available.

Q: Does it work with streaming? Yes. Compression happens before the request is sent. Streaming responses are unaffected.

Q: How much latency does it add? 15-200ms depending on content size and type. Small JSON arrays take ~15ms, large tool outputs take 100-200ms. The token savings typically save far more time on the LLM side than compression adds — a 50% token reduction on a Sonnet call saves seconds of generation time. See Latency Benchmarks for real numbers.