Phase 1 Day 6 — the architectural milestone of Phase 1. OLP is no longer
a single-provider proxy with cache; it is now a multi-provider router
with idempotent-failure-safe fallback. ADR 0004 ratified in v0.1 governance
is fully implemented for D9 scope. Configuration-driven chains activate
when a user populates ~/.olp/config.json routing.chains; at v0.1 default
(empty chains), behaviour is single-hop pass-through identical to D5.
Files:
NEW: lib/fallback/engine.mjs (~470 lines) — Trigger taxonomy, chain
advancement, first-chunk safety, observability annotation.
MOD: server.mjs (+80 lines net) — wires executeWithFallback between IR
construction and provider.spawn. Per-hop cache key isolation
(ADR 0005 § Cross-provider fallback). Test seams added:
__setFallbackConfig, __resetFallbackConfig, __clearCache.
MOD: test-features.mjs (+845 lines, 6 new suites = +55 tests).
Authority citations:
ADR 0004 § Decision § Trigger taxonomy — Hard / Soft / Deterministic
(deferred) / Cost-aware (deferred) implemented exactly per spec.
ADR 0004 § Decision § Fallback safety — first-chunk rule satisfied at
D9 by buffering composition (executeHopFn = collectAllChunks; server
writes to res only after engine returns).
ADR 0004 § Decision § Chain advancement — one-at-a-time iteration;
originalError preserved from FIRST hop (not last) on exhaustion.
ADR 0004 § Decision § No fallback for client-side errors — HTTP 400/
401/403/404/422 stop the chain immediately; AUTH_MISSING also stops
immediately (user-config failure, not provider-quota).
ADR 0004 § Decision § Observability headers — X-OLP-Fallback-Hops set
from engine return value; X-OLP-Fallback-Exhausted lists tried
providers on exhaustion.
ADR 0005 § Cross-provider fallback cache behavior — each fallback hop
computes a fresh cache key with the hop's (provider, model) tuple;
primary's cache entries cannot leak to secondary's hop.
Reviewer chain (Iron Rule 10):
Implementer: sonnet (general-purpose).
Fresh-context reviewer: opus. Verdict APPROVE_WITH_MINOR.
Reviewer ran npm test (277/277 pass), read ADR 0004 + ADR 0005 end-
to-end, verified first-chunk-safety composition, checked all
trigger taxonomy mappings.
Reviewer non-blocking findings folded in this commit:
1. Test label at test-features.mjs:3756 clarified. Original title
"client error (400) → does NOT fall back" was misleading because
the test actually exercises both-fail SPAWN_FAILED → exhausted
path (400-no-fallback semantic is covered at unit level instead).
Renamed + commented to match actual behaviour.
2. triedProviders semantic (includes soft-skipped) documented in
engine.mjs comment near the soft-trigger branch.
3. SOFT_TRIGGER synthetic code documented in engine.mjs as engine-
internal, NOT a member of base.mjs PROVIDER_ERROR_CODES.
Reviewer non-blocking suggestions deferred (open D-later questions):
- Q1 cacheStatus on fallback hops: conservative 'miss', acceptable
per ADR 0005 § Per-model isolation.
- Q2 X-OLP-Fallback-Exhausted only when triedProviders > 1:
acceptable per ADR 0004 spec.
- Q3 soft-trigger quotaSnapshot always null at D9: acceptable per
ADR 0004 § Consequences/Negative graceful-degrade clause. Phase 2
will add quota poll-worker.
- Q4 loadFallbackConfigSync sync-only: acceptable for bounded
startup I/O.
Test count: 222 (D8) → 277 (D9). 6 new test suites cover trigger
taxonomy, engine chain advancement (including the load-bearing
originalError-from-FIRST-hop property), HTTP integration through
real server.mjs, soft trigger pre-fetch path, exhausted-chain
header emission.
Verification:
node --check on all touched files: clean.
npm test on Node 25.8.0: 277/277 pass in 266ms.
Hygiene grep: zero personal-name/path/token hits.
No new external npm deps.
Co-Authored-By: Claude Opus 4.7 (noreply@anthropic.com)
OLP — Open LLM Proxy
A personal- and family-scale multi-provider LLM proxy. One HTTP endpoint, many subscriptions behind it, automatic routing, automatic fallback, content-addressed caching — so your IDEs and family clients keep working as long as any of your subscriptions has quota left.
Status: v0.1 — bootstrap. Most of this README is a skeleton; sections marked placeholder land alongside the relevant phase of work (see phase plan).
Why OLP
On 2026-05-14, Anthropic announced (effective 2026-06-15) that claude -p, the Agent SDK, and third-party agent traffic move out of the Pro/Max subscription pool into a separate fixed monthly Agent SDK Credit pool. OCP, OLP's predecessor, was a proxy around a single CLI — its core assumption was "subscription = unlimited within rate limits". That assumption breaks for Anthropic on the effective date.
The structural response is to stop relying on one provider's subscription terms remaining favourable. OLP spreads risk across multiple providers whose subscriptions still include CLI/programmatic use, routes intelligently between them, and caches aggressively so every request that does spawn a CLI counts.
OLP is not: a commercial multi-tenant SaaS; an enterprise gateway competing with LiteLLM / OpenCode / CLIProxyAPI on breadth; a model-capability router ("route to the smartest model" — you pick the model); a conversation-state store (your client handles that).
See ALIGNMENT.md for OLP's constitution and docs/adr/ for the founding ADRs.
Quick Start
placeholder — lands with Phase 1.
Anticipated shape:
# install
npm install -g @dtzp555-max/olp
# run setup (writes ~/.olp/config.json, asks which providers to enable)
olp setup
# start the proxy (default port 3456 — same as OCP if you migrate)
olp start
# point your IDE at http://localhost:3456/v1/chat/completions with the OLP API key from `olp keys list`.
Supported Providers
Source of truth: models-registry.json. This table is regenerated from the registry per the release_kit overlay; do not edit it out of sync.
OLP distinguishes Candidate Providers (declared as intended, not yet pinned) from Enabled Providers (authority pin filled + plugin landed + Phase audit passed). The v0.1 founding commit ships zero Enabled Providers — enablement is a Phase audit deliverable, not a bootstrap claim. See ALIGNMENT.md § Provider Inventory for the transition gate.
Candidate Providers
| Provider key | CLI | Subscription / auth | Anticipated Tier | Anticipated Phase |
|---|---|---|---|---|
anthropic |
claude -p |
Pro / Max OAuth (pre-2026-06-15); Agent SDK Credit pool after | D (re-eval post-2026-06-15) | Phase 1 |
openai |
codex exec --json |
ChatGPT Pro OAuth or API key | D | Phase 2 |
mistral |
vibe --prompt --output json |
Le Chat Pro API key | D | Phase 3 |
grok |
grok -p --output-format streaming-json |
xAI Build xai-... API key |
C | Phase 8+ |
kimi |
kimi -p --output-format stream-json |
Moonshot Kimi API key | C | Phase 8+ |
minimax |
TBD | MiniMax Token Plan (¥29+/mo) | B | Phase 8+ |
glm |
TBD | Zhipu Coding Plan ($10+/mo) | B | Phase 8+ |
qwen |
TBD | Alibaba Coding Plan ($50/mo) | B | Phase 8+ |
Risk tier guide. D = permissive / safe (eligible for default-enabled); C = tightening signal, no enforcement history (opt-in); B = service-level key revocation risk (opt-in + consent); A = excluded by default (cannot be opt-in enabled). Tier B providers prompt for explicit consent on first enable and record consent in ~/.olp/config.json. See ALIGNMENT.md § Risk Tier Framework.
Excluded by default (Tier A — evidence-backed, pending primary-source pin). Google Antigravity. See ADR 0006 for the named-prohibition + no-cost-advantage + reinstatement-friction rationale, and for the primary-source pinning follow-up that may force a Tier reconsideration if the Google FAQ language cannot be sourced within 90 days of 2026-05-23.
Configuration
placeholder — full configuration reference lands with Phase 4 (fallback engine).
OLP reads its config from ~/.olp/config.json. The minimum useful shape:
{
"routing": {
"chains": {
"<requested-model>": [
{ "provider": "<key>", "model": "<provider-model-id>" },
{ "provider": "<key>", "model": "<provider-model-id>" }
]
},
"soft_triggers": {
"<provider-key>": { "<trigger>": <threshold> }
}
}
}
Trigger types, fallback safety, idempotency rules, and the full example config land here when Phase 4 ships. See ADR 0004 (Fallback Engine Semantics & Safety) for the design.
API Endpoints
placeholder — full table lands as each endpoint lands.
| Endpoint | Method | Phase | Description |
|---|---|---|---|
/v1/chat/completions |
POST | 1 | OpenAI-compatible Chat Completions entry. Internally normalized to IR, dispatched to a provider plugin, response shape converted back. |
/v1/models |
GET | 1 | Lists models from models-registry.json. |
/health |
GET | 1 | Per-provider health snapshot (owner-only). |
/cache/stats |
GET | 5 | Cache hit rate, by-provider breakdown. |
/v0/management/quota |
GET | 6 | Per-provider quota / credit pool status (best-effort). |
/dashboard |
GET | 6 | Owner-only dashboard (localhost-bound by default). |
Environment Variables
placeholder — full table lands per-phase as variables are introduced.
| Variable | Default | Description |
|---|---|---|
OLP_PORT |
3456 |
HTTP listener port. |
OLP_HOME |
~/.olp |
Config, providers, keys, cache, logs root. |
OLP_LOG_LEVEL |
info |
One of error, warn, info, debug. |
Further variables (per-provider auth path overrides, cache size limits, fallback-engine knobs) land with the relevant phase.
Response Headers
Every response served through OLP carries:
X-OLP-Provider-Used: <provider-key>— which provider's plugin served the request.X-OLP-Model-Used: <model-id>— which model the served provider used.X-OLP-Fallback-Hops: <n>— number of fallback hops (0if served by the primary chain entry).X-OLP-Cache: hit | miss | bypass— cache layer outcome.X-OLP-Latency-Ms: <ms>— end-to-end latency observed at the proxy.
If a fallback chain is exhausted, X-OLP-Fallback-Exhausted lists the tried providers in order.
Architecture
OLP is a Node.js (ESM, .mjs) HTTP proxy with no build step and minimal dependencies. The high-level shape:
- Entry surface —
server.mjshandles/v1/chat/completionsand the administrative endpoints. Governed by OpenAI's/v1/chat/completionsspecification as the wire authority. SeeALIGNMENT.md§ Authorities. - Intermediate Representation (IR) —
lib/ir/normalizes between the entry surface and provider-native shapes. The IR is the lingua franca; any extension is an ADR 0003 amendment. - Provider plugins —
lib/providers/<name>.mjs. Each plugin implements the contract in ADR 0002 (Plugin Architecture for Providers), spawns its CLI, and translates between IR and provider-native IO. - Cache layer —
lib/cache/is a content-addressed cache keyed on(provider, model, messages, tools, temperature, response_format, cache_control). Per-key isolation, prompt-caching bypass, chunked stream replay, and singleflight. See ADR 0005 (Cache Layer Cross-Provider Design). - Fallback engine —
lib/fallback/advances a configured chain one provider at a time on configured triggers, never retrying after the first response chunk has been emitted to the client. See ADR 0004. - Multi-key auth —
lib/keys.mjscarries OCP's per-OLP-key namespace isolation forward. Each OLP API key has independent quota, cache namespace, and audit log; each key declares which providers it can access.
Read the ADRs in docs/adr/ in order before proposing structural changes.
Phase plan
OLP lands in phases. Each phase has its own PR series and Iron-Rule-10 reviewer; this README's placeholders are filled per-phase via the release_kit overlay.
- Phase 0 — Repo bootstrap,
ALIGNMENT.md, founding ADRs, CI workflows, PR template. (current) - Phase 1 —
server.mjsskeleton, IR, Anthropic plugin, cache D1+D4. Port from OCP. - Phase 2 — OpenAI Codex plugin.
- Phase 3 — Mistral Vibe plugin.
- Phase 4 — Fallback engine + routing chains config + quota poll worker.
- Phase 5 — Cache cross-provider hardening (D2+D3).
- Phase 6 — Dashboard + observability (
/v0/management/quota). - Phase 7 — Release v0.1, OCP enters maintenance.
- Phase 8+ — Optional Grok / Kimi / tier-2 plugins; provider-native protocol endpoints; deterministic triggers.
Full spec (decision rationale, open questions, risks): ~/.cc-rules/memory/projects/olp_v0_1_spec.md on the maintainer's workstations.
Migration from OCP
placeholder — scripts/migrate-from-ocp.mjs lands with Phase 7.
Anticipated user-facing flow (target: <5 minutes):
- Stop OCP (
launchctl bootoutthe OCP service orocp stop). - Install OLP.
- Run
olp migrate-from-ocp— copies~/.ocp/keys/to~/.olp/keys/and points provider plugins at OCP's existing auth artifacts where applicable. - Start OLP. Clients pointing at port 3456 keep working; their existing OLP API keys remain valid.
OCP's cache directory is not migrated: OLP's cache key format includes provider+model and warms cold naturally. OCP enters maintenance mode (stability fixes only) when OLP v0.1 ships; new development happens in OLP.
License
MIT.
Acknowledgements
OLP evolved from OCP (Open Claude Proxy). OCP's per-key isolation model, cache-layer design (D1–D4), dashboard, and alignment-constitution discipline are all carried forward. The structural generalization from single-CLI to multi-provider is what makes this a new project rather than an OCP minor version — see ALIGNMENT.md § Reference: How OCP's cli.js discipline maps to OLP.
Authors: project maintainer (with AI drafting assistance).