mirror of https://github.com/headroomlabs-ai/headroom.git synced 2026-08-27 14:17:10 -04:00

chopratejas 0ce2243dfb docs: add Realignment plan (40 PRs, 9 phases)

Comprehensive PR-by-PR plan to realign Headroom around live-zone-only
compression with prefix-cache safety as a non-negotiable invariant.
Drafted from a 10-agent deep audit against the LLM-proxy compression
guide.

- 14 documents under REALIGNMENT/
- 72 ranked bugs (P0 cache-killers through P6 test-infra)
- 40 feature PRs + 10 test-infra PRs across 9 phases
- ~25K LOC retirement (ICM + scoring + relevance + rolling-window
  + summarizer + tool-crusher + LiteLLM-fake-Bedrock)
- Preserves TOIN, CCR, Kompress-base per user direction
- Auth-mode policy gates (PAYG / OAuth / subscription)
- Phase 3 cache stabilization surface (tool-sort, schema-sort,
  cache_control auto-place, prompt_cache_key)
- Native Bedrock SigV4 + Vertex ADC handlers
- Test infrastructure: SHA-256 byte-faithful gate, SSE corner cases,
  property tests, real-traffic shadow

2026-05-01 23:34:46 -07:00

5.8 KiB

Raw Blame History

Headroom Realignment — Index

Status: Drafted 2026-05-01 from a 10-agent deep audit against ~/Downloads/llm-proxy-compression-guide.md. Owner: chopratejas Goal: Move the entire codebase to Rust, preserve prefix cache, retain compression value, integrate RTK end-to-end, and gate compression policy by auth mode (PAYG / OAuth / subscription).

Read in this order

00-overview.md — executive summary; the wrong mental model; what changes
01-bug-list.md — comprehensive ranked bug list with file:line and guide §
02-architecture.md — the realigned target architecture
Phase docs (PR-by-PR, executable):
- 03-phase-A-lockdown.md — start here: stop-the-bleeding (8 PRs, ~1 week)
- 04-phase-B-live-zone.md — live-zone-only compression (7 PRs, ~2 weeks)
- 05-phase-C-rust-proxy.md — port handlers to Rust (5 PRs, ~3 weeks)
- 06-phase-D-bedrock-vertex.md — native envelopes (4 PRs, ~2 weeks)
- 07-phase-E-cache-stabilization.md — Phase 3 stabilization (6 PRs, ~1 week)
- 08-phase-F-auth-mode.md — auth-mode policy gates (4 PRs, ~1 week)
- 09-phase-G-rtk-observability.md — RTK breadth + metrics (3 PRs, ~1 week)
- 10-phase-H-python-retirement.md — delete Python proxy (3 PRs, ~2 weeks)
- 11-phase-I-test-infra.md — test/CI gates (parallel)
12-decisions-needed.md — open questions

Conventions

Branch name: realign-<phase-letter><pr-num>-<slug>. Example: realign-A1-icm-passthrough.
Worktree path: ~/claude-projects/headroom-worktrees/realign-<phase><num>-<slug>. Use git worktree add so each PR is an isolated checkout.
Commit prefix: fix: for Rust-migration phase commits (per project memory — feat: would inflate semantic-release version).
No Co-Authored-By: Claude trailer (per project memory).
Pre-push gate: make ci-precheck per project memory; never push without it.

Phase totals

Phase	PRs	LOC delta (est.)	Calendar (sequential)
A — Lockdown	8	-200 / +400	1 week
B — Live-zone engine	7	-10,000 / +1,500	2 weeks
C — Rust proxy paths	5	-2,000 / +5,000	3 weeks
D — Bedrock/Vertex native	4	-800 / +2,500	2 weeks
E — Cache stabilization	6	-100 / +900	1 week
F — Auth-mode policy	4	-50 / +600	1 week
G — RTK + observability	3	-50 / +400	1 week
H — Python retirement	3	-15,000 / +200	2 weeks
I — Test infra	parallel	+2,000	continuous
Total	40	~-28,000 / +13,500	~13 weeks sequential, ~8 weeks parallel

Cross-cutting invariants

These never get violated by any PR:

Bytes that the proxy doesn't intend to modify must arrive at upstream byte-equal (SHA-256) to bytes that arrived at the proxy. (§1.9)
The cache hot zone — system, tools, old turns, reasoning/thinking/redacted/compaction items — is never modified. (§10)
Compression is append-only: only the live zone (latest user message, latest tool/function/shell/patch outputs) is ever rewritten. (§6.4 + §10.3)
Compression is deterministic: same input bytes → same output bytes. (§7.1)
Tool definitions are normalized (sorted), never compressed. (§8.5)
signature, encrypted_content, redacted_thinking.data, compaction.encrypted_content are passthrough-only. (§2.7, §2.8, §4.3, §4.8, §10.1)
TOIN never alters request-time decisions; it observes and publishes recommendations between deploys. (§7.1, §11.17)
CCR markers and the ccr_retrieve tool are present on every request for a session that ever did CCR — never toggled. (§6.3 #2)
Authorization header is forwarded byte-faithfully and never logged or persisted unredacted.
Auth mode (PAYG / OAuth / subscription) gates compression policy; subscription mode runs in stealth (no X-Headroom-* upstream, no beta drift, no UA mutation, no accept-encoding strip).

Preserved primitives (per user direction)

TOIN — refactored to strict observation-only; per-tenant aggregation key.
CCR — hardened with persistent backend + always-on tool registration.
Kompress-base — stays as plain-text compressor (§8.6); Rust port via ort later.
ContentRouter — the architecturally correct piece (~2150 LOC); ported to Rust as the live-zone block dispatcher.
Type-aware compressors — SmartCrusher, Code, Log, Search, Diff (already in Rust); kept.
signals/ Rust trait module — keeps; drives live-zone consumers.
tokenizer/ Rust — keeps.
safety.rs — tool-pair atomicity logic; moved to transforms/safety.rs after Phase B.

Retired (~25K LOC)

ICM (Python intelligent_context.py, Rust context/manager.rs)
RollingWindow, ProgressiveSummarizer, scoring.py, tool_crusher.py (Python)
crates/headroom-core/src/scoring/, relevance/, most of context/ (Rust)
crates/headroom-proxy/src/compression/icm.rs
headroom/transforms/cache_aligner.py rewrite path (keep detector + warning)
headroom/proxy/server.py, handlers/anthropic.py, handlers/openai.py, handlers/streaming.py, handlers/gemini.py, responses_converter.py, memory_handler.py, memory_tool_adapter.py, semantic_cache.py, batch.py — once Rust hits parity (Phase H)
headroom/backends/litellm.py Bedrock/Vertex converter — replaced by native envelopes (Phase D)
MessageScorer Rust port (PR #338, #343) — wasted work; deleted in Phase B

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