diff --git a/README.md b/README.md
index 014d42a..7d1a9c8 100644
--- a/README.md
+++ b/README.md
@@ -14,11 +14,13 @@ attach-guard is a Claude Code plugin that intercepts package installation comman
 
 - Installs as a Claude Code plugin — no manual hook configuration needed
 - Intercepts `npm install`, `pnpm add`, `pip install`, `go get`, and `cargo add` commands via PreToolUse hooks
-- Checks package scores, age, and alerts via Socket.dev
-- Denies known malware and low-score packages automatically
-- Asks for confirmation on gray-band packages
+- Evaluates packages with the configured provider before install commands run
+- Uses the current Socket.dev adapter only as an explicit bring-your-own-token local provider, not a hosted/default scoring source
+- Denies known malware and high-confidence dangerous packages automatically
+- Asks for confirmation on gray-band packages and provider-unavailable cases in local mode
 - Rewrites unpinned installs to safe pinned versions when possible
-- Fails closed when the provider is unavailable
+
+Attach Open Score is the first-party provider direction and is not wired in yet; see [Attach Open Score provider semantics](docs/OPEN_SCORE_PROVIDER.md) for the planned integration contract.
 - Logs every decision to a local JSONL audit trail
 
 ## Smart Version Replacement: Block Without Breaking Flow
@@ -27,20 +29,20 @@ Most security tools just say "no." attach-guard says "no, but here's a safe alte
 
 When a risky version is blocked, attach-guard finds the newest version that passes policy and offers it as a replacement. Claude sees the safe alternative and can proceed immediately — your flow doesn't stop, it gets redirected to a safe path.
 
-**npm** — axios v1.14.1 and v0.30.4 were [compromised versions](https://socket.dev/blog/axios-npm-account-compromise) published via a hijacked maintainer account:
+**npm** — axios v1.14.1 and v0.30.4 were publicly reported compromised versions published via a hijacked maintainer account:
 
 ```
 > npm install axios
 
 attach-guard evaluates:
-  axios@1.14.1  -->  DENY (supply chain score 40, below threshold 50 — compromised version)
-  axios@1.14.0  -->  ALLOW (supply chain score 71, passes all policy checks)
+  axios@1.14.1  -->  DENY (known compromised version)
+  axios@1.14.0  -->  ALLOW (passes configured policy checks)
 
 Result: ASK + rewritten command
   "npm install axios@1.14.0"
 ```
 
-**pip** — litellm v1.82.7 and v1.82.8 were [malicious versions](https://socket.dev/npm/package/litellm) published to PyPI:
+**pip** — litellm v1.82.7 and v1.82.8 were malicious versions published to PyPI:
 
 ```
 > pip install litellm
@@ -53,7 +55,7 @@ Result: ASK + rewritten command
   "pip install litellm==1.82.6"
 ```
 
-These are real examples — attach-guard blocks compromised versions automatically based on their supply chain scores.
+These examples illustrate the current enforcement flow: attach-guard blocks known compromised or policy-failing versions and offers a safe pinned alternative when one is available.
 
 | Scenario | Example | Decision | What happens |
 |---|---|---|---|
@@ -87,7 +89,7 @@ Security enforcement requires interception at the tool-call boundary, before exe
 
 ### Quick Start: Claude Code Plugin
 
-The fastest way to try attach-guard. Requires a [Socket.dev](https://socket.dev) API token (free tier available).
+The fastest way to try the current packaged plugin. Today's released plugin uses the local bring-your-own-token Socket.dev provider for real scoring. Attach Open Score is the first-party direction and is not wired in yet; Socket must not be treated as hosted/default Attach scoring.
 
 ```bash
 # Add the marketplace and install (one-time)
@@ -101,7 +103,7 @@ Or from within a Claude Code session:
 /plugin install attach-guard@attach-dev
 ```
 
-During installation or enablement, Claude Code will prompt for your Socket API token (stored securely in your system keychain). Get a free token at [socket.dev](https://socket.dev).
+During installation or enablement, the current Socket-backed plugin path prompts for your Socket API token (stored securely in your system keychain). Get a free token at [socket.dev](https://socket.dev). This token is for local BYO-provider use only.
 
 > **If the install/enable prompt didn't appear**, re-trigger it with:
 > ```bash
@@ -136,7 +138,7 @@ For use without the plugin system, or to install the binary globally.
 #### Prerequisites
 
 - [Go 1.21+](https://go.dev/dl/) (to build from source; not needed for the plugin install above)
-- A [Socket.dev](https://socket.dev) API token (free tier available)
+- A [Socket.dev](https://socket.dev) API token only when using the current Socket BYO-token provider path
 
 #### Step 1: Build and install the binary
 
@@ -164,7 +166,7 @@ attach-guard version
 # attach-guard v0.1.0
 ```
 
-#### Step 2: Set up your Socket API token
+#### Step 2: Set up a Socket API token for the current BYO-provider path
 
 ```bash
 export SOCKET_API_TOKEN="your-token-here"
@@ -213,7 +215,7 @@ Try installing a known-compromised version to verify attach-guard blocks it:
 > Install axios@1.14.1
 
 Claude: I'll install axios@1.14.1.
-[attach-guard] deny: axios@1.14.1: supply chain score 40 is below minimum threshold 50
+[attach-guard] deny: axios@1.14.1: known compromised version
 ```
 
 Then try a safe version:
@@ -275,9 +277,11 @@ attach-guard hook
 
 Default config location: `~/.attach-guard/config.yaml`
 
+Current provider configuration still defaults to the Socket adapter in code. Treat this as a legacy/local BYO-token default until the Attach Open Score provider lands; do not use Socket as hosted/default Attach scoring.
+
 ```yaml
 provider:
-  kind: socket                     # risk intelligence provider
+  kind: socket                     # explicit BYO-token local provider today; Open Score is the first-party direction
   api_token_env: SOCKET_API_TOKEN
 policy:
   deny_known_malware: true
@@ -334,12 +338,14 @@ Highest priority wins (later sources override earlier):
 ### Unpinned version handling
 
 When you run an unpinned supported command such as `npm install axios`, `pip install requests`, `go get golang.org/x/net`, or `cargo add serde`:
-- attach-guard fetches candidate versions from the matching registry and scores them via Socket.dev
+- attach-guard fetches candidate versions from the configured provider and evaluates them against policy
 - If the latest passes policy, the command runs as-is
 - If the latest fails but an older version passes, attach-guard suggests a rewrite using ecosystem-native syntax
 - In Claude Code mode: returns `ask` with the rewritten command via `updatedInput`
 - If no version passes, denies
 
+Attach Open Score integration should be verdict-first: `ALLOW` → allow, `ASK` → ask, `DENY` → deny, and `UNKNOWN` → ask/warn locally by default. CI/team policy may map unknowns to deny by explicit configuration. See [Attach Open Score provider semantics](docs/OPEN_SCORE_PROVIDER.md).
+
 ### Failure handling
 
 - Local/interactive mode: asks on provider failure
@@ -356,18 +362,18 @@ Every decision is logged to `~/.attach-guard/audit.jsonl`:
   "user": "dev",
   "cwd": "/home/dev/project",
   "package_manager": "npm",
-  "original_command": "npm install axios@1.14.1",
+  "original_command": "npm install example-malware@1.0.0",
   "decision": "deny",
-  "reason": "axios@1.14.1: supply chain score 40 is below minimum threshold 50",
-  "packages": [{"ecosystem":"npm","name":"axios","selected_version":"1.14.1","score":{"supply_chain":40,"overall":40}}],
-  "provider": "socket",
+  "reason": "example-malware@1.0.0: known malware alert",
+  "packages": [{"ecosystem":"npm","name":"example-malware","selected_version":"1.0.0","score":{"supply_chain":0,"overall":0},"alerts":[{"severity":"critical","title":"known malware","category":"malware"}]}],
+  "provider": "mock",
   "mode": "claude"
 }
 ```
 
-## API Quota
+## Socket BYO-token provider quota
 
-attach-guard uses the [Socket.dev API](https://socket.dev) for package risk scoring. The free tier provides **500 quota units per hour**.
+The current Socket adapter uses the [Socket.dev API](https://socket.dev) when the user explicitly configures the BYO-token Socket provider. This section is for that local provider path only; Socket data must not be used as a default Attach Open Score input/source absent an explicit partnership.
 
 | Ecosystem | Endpoint | Cost per call |
 |---|---|---|
@@ -380,9 +386,9 @@ attach-guard uses the [Socket.dev API](https://socket.dev) for package risk scor
 - Pinned installs (e.g. `pip install litellm==1.82.8`) use one call to score a single version
 - Unpinned installs (e.g. `pip install litellm`) use one batch call to score up to 10 candidate versions
 
-**When quota is exhausted**, scoring calls fail and attach-guard falls back to zero scores. This means:
-- Pinned installs are **denied** (score 0 < threshold 50) — safe, fails closed
-- Unpinned installs show "no acceptable version found" instead of offering a safe alternative — the version rewrite feature requires real scores to identify which version passes policy
+**When quota is exhausted**, provider calls fail. In current behavior this means:
+- Pinned installs are **denied** because the provider could not return an acceptable evaluation — safe, fails closed
+- Unpinned installs show "no acceptable version found" instead of offering a safe alternative — the version rewrite feature requires real provider results to identify which version passes policy
 
 To check your remaining quota:
 ```bash
@@ -395,7 +401,8 @@ Quota resets hourly. For higher limits, see [Socket.dev pricing](https://socket.
 
 - Direct `pip` / `pip3` (including `uv pip`), `go get` / `go install`, and `cargo add` / `cargo install` are supported; `python -m pip` remains passthrough for now
 - pip extras/range specs, Cargo requirement syntax, and non-semver Go queries are intentionally passed through for manual review rather than being auto-evaluated
-- PyPI, Go, and Cargo scoring uses Socket's `POST /v0/purl` endpoint which has higher quota cost (100 units) compared to npm (10 units)
+- Current released provider implementation is Socket BYO-token/local; Attach Open Score first-party provider integration is the next direction
+- PyPI, Go, and Cargo scoring through the Socket BYO provider uses Socket's `POST /v0/purl` endpoint, which has higher quota cost (100 units) compared to npm (10 units)
 - No transitive dependency analysis
 - No lockfile graph support
 - Single provider at a time
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index b5bd94a..de8438f 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -36,7 +36,7 @@ raw command string
          │
          ▼
 ┌──────────┐
-│  Provider │ ── Socket adapter fetches scores, versions, alerts
+│  Provider │ ── scores, versions, alerts today; future Open Score integration maps verdicts
 └────┬─────┘
      │
      ▼
@@ -71,7 +71,12 @@ type Provider interface {
 }
 ```
 
-The Socket adapter normalizes Socket API responses into internal `VersionInfo` and `PackageScore` types. No Socket-specific types leak into the policy engine.
+Current implementation status:
+- the shipped adapter is Socket-backed and should be treated as an explicit local BYO-token provider
+- the first-party default direction is Attach Open Score; see [`docs/OPEN_SCORE_PROVIDER.md`](OPEN_SCORE_PROVIDER.md) for verdict mapping and source/legal constraints
+- no proprietary provider types should leak into the policy engine
+
+The current Socket adapter normalizes Socket API responses into internal `VersionInfo` and `PackageScore` types. Future Open Score integration should avoid directly mapping Open Score's risk score into the existing safety-score fields because the polarity is opposite; use verdict-first mapping or an explicit transform with tests.
 
 To add a new provider:
 1. Implement the `Provider` interface
diff --git a/docs/OPEN_SCORE_PROVIDER.md b/docs/OPEN_SCORE_PROVIDER.md
new file mode 100644
index 0000000..54c5cef
--- /dev/null
+++ b/docs/OPEN_SCORE_PROVIDER.md
@@ -0,0 +1,155 @@
+# Attach Open Score provider semantics
+
+Status: design note for the attach-guard integration path
+Audience: attach-guard maintainers, Attach Open Score implementers, policy authors
+
+## Goal
+
+attach-guard should treat Attach Open Score as the first-party default scoring direction while keeping proprietary providers, including Socket, as bring-your-own-token local integrations unless an explicit partnership permits broader hosted/default use.
+
+This note defines how Attach Open Score verdicts should map into attach-guard behavior before code is added.
+
+## Source and licensing posture
+
+Allowed default Attach Open Score inputs are public, open, or otherwise terms-permitted sources with attribution and source references, including OSV, GitHub Advisory Database, deps.dev, OpenSSF Scorecard, public registry metadata, and package artifacts where allowed by each source's license/terms.
+
+Forbidden for default or hosted Attach scoring unless explicitly reviewed and permitted:
+
+- copying, scraping, reselling, or redistributing Socket/Snyk/Aikido/Sonatype/Endor scores or vendor data
+- using proprietary vendor scores as calibration labels, training data, fixtures, public examples, or threshold targets
+- exposing a paid API that behaves like a raw upstream dataset redistribution service
+
+Socket can remain useful as a local BYO-token provider, but it must not be framed as the default Attach scoring source.
+
+## Decision mapping
+
+Attach Open Score v0 emits uppercase public decisions:
+
+| Attach Open Score | attach-guard behavior | Local default | CI/team default |
+|---|---|---|---|
+| `ALLOW` | allow install | allow | allow |
+| `ASK` | require review / user confirmation | ask/warn | configurable; often deny or require policy approval |
+| `DENY` | block install | deny | deny |
+| `UNKNOWN` | insufficient evidence | ask/warn | configurable; often deny or require policy approval |
+
+attach-guard currently has internal `allow`, `ask`, and `deny` decisions only. Until `unknown` becomes a first-class internal decision, Open Score `UNKNOWN` should map to `ask` at the provider/policy boundary for local mode. CI/team policy may map `UNKNOWN` to deny by explicit configuration.
+
+## Integration boundary
+
+The preferred v0 implementation should avoid forcing Open Score through the existing Socket-style `PackageScore` threshold path. Add an explicit verdict-carrying result at the provider/policy boundary, for example:
+
+```go
+type ProviderVerdict struct {
+    Decision   string   // ALLOW, ASK, DENY, UNKNOWN
+    RiskScore  *int     // Open Score risk score, higher means riskier
+    Reasons    []string // Open Score reason codes or rendered reason IDs
+    SourceRefs []string // source reference IDs/URLs safe for audit output
+}
+```
+
+For the next implementation pass, use option 1: extend the provider/policy result shape so policy can consume `ProviderVerdict` directly. Legacy Socket score thresholds should remain provider-specific signals, not the generic contract for Open Score.
+
+Decision precedence should remain conservative:
+
+- explicit local/team denylist beats provider `ALLOW`
+- known malware or high-confidence critical evidence beats provider `ALLOW`
+- provider `DENY` blocks unless an explicit allowlist/policy override exists
+- provider `ASK` and `UNKNOWN` require confirmation locally and may fail policy in CI/team mode
+- provider unavailability maps to local ask/warn by default, not silent allow
+
+## Score polarity warning
+
+Attach Open Score's numeric `score` is a risk score: higher means riskier.
+
+attach-guard's current `PackageScore.SupplyChain` and `PackageScore.Overall` fields are treated as safety-ish scores: lower means worse, and the current policy denies when `supply_chain < threshold`.
+
+Therefore, do not map Open Score `score` directly into `PackageScore.SupplyChain` or `Overall`. That would invert behavior.
+
+Acceptable implementation patterns:
+
+1. **Verdict-first bridge** — map Open Score `decision` directly to attach-guard allow/ask/deny behavior, and preserve score/reasons/source refs for explanation/audit UX.
+2. **Explicit score transform** — if existing threshold code must be reused temporarily, transform `safety_score = 100 - risk_score` and add tests proving polarity for ALLOW/ASK/DENY/UNKNOWN fixtures.
+3. **Policy refactor** — make attach-guard policy understand decision-first verdicts and keep risk score as supporting context rather than the primary decision variable.
+
+The preferred v0 integration is verdict-first. This leaves less room for accidental polarity inversions.
+
+## Reason and source propagation
+
+Open Score verdicts include reason codes and `source_refs`. attach-guard should preserve these in user-facing reasons and audit logs where possible.
+
+Initial implementation can compress reasons into a human-readable reason string, but should avoid discarding structured data permanently. Future audit entries should be able to include:
+
+- Open Score reason codes
+- severity / decision effect
+- source reference IDs
+- source names and URLs where safe
+- evaluation timestamp and TTL
+
+## Provider availability
+
+Local developer mode should not default to fail-closed on provider unavailability or unknown evidence. Default local behavior:
+
+```text
+provider unavailable → ASK / warn
+UNKNOWN verdict      → ASK / warn
+```
+
+CI/team mode can be stricter by explicit configuration:
+
+```text
+provider unavailable → DENY or policy failure
+UNKNOWN verdict      → DENY or policy failure
+```
+
+## Config direction
+
+Current config supports a single provider kind and an environment override:
+
+```yaml
+provider:
+  kind: socket
+```
+
+```bash
+ATTACH_GUARD_PROVIDER=mock
+```
+
+Future provider kind for this integration should be `open-score`.
+
+```yaml
+provider:
+  kind: open-score
+  endpoint: http://127.0.0.1:8757      # local or hosted Attach Open Score-compatible HTTP endpoint
+  timeout_seconds: 5
+policy:
+  unknown_behavior:
+    local: ask                         # ask | deny | allow
+    ci: deny
+  provider_unavailable_behavior:
+    local: ask                         # ask | deny | allow
+    ci: deny
+```
+
+The v0 implementation target is an HTTP client provider. Embedded Go package or external CLI modes can be added later, but should not block the first provider pass.
+
+Socket provider docs should show explicit opt-in:
+
+```yaml
+provider:
+  kind: socket
+  api_token_env: SOCKET_API_TOKEN
+```
+
+## Implementation checklist
+
+Before adding code:
+
+- [x] Provider kind for the next pass: `open-score`.
+- [x] Runtime shape for the next pass: HTTP client provider against a local or hosted Attach Open Score-compatible endpoint.
+- [ ] Extend provider/policy result shape with a verdict-first result such as `ProviderVerdict`.
+- [ ] Add fixture-driven tests using public-safe synthetic verdicts.
+- [ ] Test `UNKNOWN` mapping in local and CI modes via `policy.unknown_behavior`.
+- [ ] Test provider-unavailable behavior via `policy.provider_unavailable_behavior`.
+- [ ] Test score polarity so high-risk scores cannot accidentally become high-safety scores.
+- [ ] Preserve source/legal attribution in docs and audit output.
+- [ ] Keep Socket as explicit BYO-token/local provider.