feat: establish standalone Rstack Context runtime

.github/workflows/ci.yml

@@ -0,0 +1,41 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+permissions: {}
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Setup Node.js
+        uses: actions/setup-node@249970729cb0ef3589644e2896645e5dc5ba9c38 # v6
+        with:
+          node-version: 24.15.0
+          cache: pnpm
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Check
+        run: pnpm check
+
+      - name: Build
+        run: pnpm build
+
+      - name: Test
+        run: pnpm test
+
+      - name: Pack
+        run: |
+          mkdir -p .artifacts
+          pnpm pack --pack-destination .artifacts

.github/workflows/pkg-pr-new.yml

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+name: Publish Package Previews
+
+on:
+  pull_request:
+    branches: [main]
+
+permissions: {}
+
+jobs:
+  publish:
+    if: github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Setup Node.js
+        uses: actions/setup-node@249970729cb0ef3589644e2896645e5dc5ba9c38 # v6
+        with:
+          node-version: 24.15.0
+          cache: pnpm
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Build
+        run: pnpm build
+
+      - name: Publish package preview
+        shell: bash
+        run: |
+          set +e
+          output=$(pnpm exec pkg-pr-new publish --pnpm --previewVersion --no-template '.' 2>&1)
+          status=$?
+          set -e
+          printf '%s\n' "$output"
+
+          if [ "$status" -eq 0 ]; then
+            exit 0
+          fi
+
+          if [[ "$output" == *'There is no workflow defined'* ]]; then
+            echo '::warning title=pkg.pr.new is not enabled::Grant the pkg.pr.new GitHub App access to rstackjs/context to publish preview packages.'
+            exit 0
+          fi
+
+          exit "$status"

.gitignore

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+.artifacts
+coverage
+dist
+dist-tests
+node_modules

.prettierignore

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+coverage
+dist
+dist-tests
+pnpm-lock.yaml

.prettierrc.json

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+{
+  "printWidth": 100,
+  "singleQuote": true
+}

AGENTS.md

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+# AGENTS.md
+
+## Stack
+
+- Use the Node.js and pnpm versions declared in `package.json`.
+- TypeScript package built with Rslib.
+- Rsbuild APIs power build-context observation.
+- Rstest runs tests and coverage.
+- Rslint performs lint and type-aware checks.
+
+## Commands
+
+```bash
+corepack enable
+pnpm install
+pnpm check
+pnpm build
+pnpm test
+pnpm test:coverage
+```
+
+## Architecture
+
+- Keep the context runtime independent of the `rstack` CLI package.
+- Do not add a Context-specific CLI command, plugin SPI, or generated lint/test wrapper configs.
+- Integrate passive builds only through the public Rstack shared-config API from RFC #504.
+- Run MCP directly through the programmatic `@rstackjs/context/mcp` stdio entry point.
+- Keep Codex and Claude plugin packaging and skills in `rstackjs/agent-skills`.
+- Preserve freshness, completeness, provenance, and evidence axes independently.
+- Missing Rstack producers must degrade to unavailable evidence rather than prevent other tools from
+  working.
+
+## Changes
+
+- Add tests for public API, store-schema, MCP-schema, or evidence-semantic changes.
+- Keep the package API and MCP tool schemas backward compatible unless a breaking change is explicit.
+- Use pkg.pr.new previews for cross-repository shared-config and Agent Skills validation.

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Rstack contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -1,2 +1,90 @@
-# context
-Rstack project context, evidence storage, and MCP runtime.
+# Rstack Context
+
+`@rstackjs/context` records and queries checkout-local build, lint, test, coverage, and Rsdoctor
+evidence while keeping freshness, completeness, and provenance explicit. The package is independent
+of Rstack CLI. Its MCP server runs directly, while passive build capture integrates through ordinary
+Rstack shared configuration.
+
+## Add build context
+
+> [!IMPORTANT]
+> This integration requires the public `define.extends()` API proposed in
+> [Rstack RFC #504](https://github.com/rstackjs/rstack-cli/discussions/504). The lower-level
+> implementation is still landing in Rstack, so keep this setup gated until a released Rstack
+> version exports that API.
+
+After that API is released, install `@rstackjs/context` and add its shared configuration to
+`rstack.config.ts`:
+
+```ts
+import { createRstackContextConfig } from '@rstackjs/context/shared-config';
+import { define } from 'rstack';
+
+define.extends([
+  createRstackContextConfig({
+    products: 'application',
+  }),
+]);
+
+define.app({
+  // Project-specific settings have the normal highest precedence.
+});
+```
+
+Use `products: 'library'` for a library-only project, or
+`products: ['application', 'library']` when the same Rstack configuration intentionally defines
+both. Product selection is explicit so adding Context does not change Rstack's automatic Rstest
+App-versus-Lib inheritance.
+
+The factory enables metadata capture by default. Set `capture: 'off'`, or set
+`RSTACK_CONTEXT=0`, to disable it. `RSTACK_CONTEXT=1` enables metadata capture for an invocation.
+
+## Run the MCP server
+
+The package exports a programmatic stdio entry point rather than adding a custom CLI command.
+
+For an MCP host configuration:
+
+```json
+{
+  "mcpServers": {
+    "rstack-context": {
+      "command": "node",
+      "args": [
+        "--input-type=module",
+        "--eval",
+        "import('@rstackjs/context/mcp').then(({ runContextMcpServer }) => runContextMcpServer())"
+      ]
+    }
+  }
+}
+```
+
+The server reads completed build observations from `.rstack/cache/context-v1`. Explicit
+`lint_snapshot` and `test_snapshot` requests use the selected package's native
+`rslint.config.*` and `rstest.config.*` files. `related_tests` lists the Rstest files related to
+one or more source files without executing test cases or writing a snapshot. Both Rstest tools
+reject a package that has no native `rstest.config.*` instead of falling back to default workspace
+discovery. None of these tools requires a custom command, a Rstack CLI plugin SPI, or generated
+wrapper configs.
+
+Codex and Claude Code workflow guidance is distributed separately by
+[`rstackjs/agent-skills`](https://github.com/rstackjs/agent-skills).
+
+## Development
+
+```bash
+corepack enable
+pnpm install
+pnpm check
+pnpm build
+pnpm test
+```
+
+The package uses Rslib for builds, Rstest for tests, and Rslint for lint and type-aware checks.
+Rsbuild remains a public integration surface for build-context observers. See the
+[context engine RFC](./docs/rfc.md) for the evidence model.
+
+Execution coverage evidence is optional and resolved against the package under test, not against
+`@rstackjs/context` itself. Install `@rstest/coverage-istanbul` or another supported Rstest
+coverage provider in the checkout being analyzed.

docs/repository-extraction.md

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+# Rstack Context ownership
+
+## Status
+
+Revised on 2026-09-23 after
+[Rstack RFC #504](https://github.com/rstackjs/rstack-cli/discussions/504) replaced the proposed
+Context-specific CLI plugin system.
+
+## Decision
+
+`rstackjs/context` owns the complete Context runtime:
+
+- the evidence model and checkout-local store;
+- Rsbuild and Rslib observers;
+- native Rslint and Rstest capture;
+- related-test discovery through Rstest's public reusable instance API;
+- Rsdoctor artifact analysis;
+- queries and diffs; and
+- the programmatic stdio MCP server.
+
+`rstackjs/agent-skills` owns installation manifests and agent workflows. Rstack CLI owns only its
+general shared-configuration feature. It does not host Context, add `rs mcp`, generate lint/test
+wrapper configs, or provide a Context plugin SPI.
+
+## Runtime architecture
+
+```mermaid
+flowchart LR
+  Host["Codex or Claude"] -->|"stdio"| MCP["@rstackjs/context/mcp"]
+  Shared["Rstack define.extends()"] --> Observer["Context build observer"]
+  Observer --> Store[("checkout-local evidence store")]
+  MCP --> Store
+  MCP -->|"explicit capture"| Lint["native Rslint config"]
+  MCP -->|"explicit preflight/capture"| Test["native Rstest config"]
+  MCP -->|"explicit file"| Doctor["Rsdoctor artifact"]
+```
+
+The stdio process is started by importing `runContextMcpServer()`. It is not a package binary or a
+custom Rstack command.
+
+## Shared-config gate
+
+Passive build integration uses `@rstackjs/context/shared-config`, but it remains release-gated until
+Rstack publishes the complete RFC #504 contract:
+
+- public `RstackConfig`;
+- public `define.extends()`;
+- shared-layer loading;
+- App and Lib native merges; and
+- merged Test configuration before automatic App-versus-Lib inheritance.
+
+The package can still ship and run its MCP, lint, test, Rsdoctor, store, and query features without
+that Rstack release. Documentation must not present passive build setup as currently available until
+the gate is satisfied.
+
+## Native test boundary
+
+Context uses `@rstest/core`'s public `loadConfig()` and reusable `createRstest()` API. It trusts
+Rstest's native config discovery order and extensions. If discovery returns no config file,
+`related_tests` and `test_snapshot` fail before constructing Rstest or writing a run manifest.
+
+`related_tests` calls `listTests({ filesOnly: true, filters: sources, related: true })`.
+`test_snapshot` runs the original source filters with `related: true`; it does not substitute the
+preflight's test paths into execution.
+
+## Compatibility
+
+- Preserve the `@rstackjs/context` package name.
+- Preserve `.rstack/cache/context-v1` reads and evidence semantics.
+- Keep producer failures independent.
+- Keep freshness, completeness, provenance, and evidence axes separate.
+- Avoid runtime or peer dependencies on `rstack`.
+- Do not preserve the abandoned CLI host APIs as compatibility shims.
+
+## Verification
+
+The repository must pass:
+
+- frozen install;
+- Rslint type-aware checks and formatting;
+- Rslib build and declaration generation;
+- the full Rstest suite;
+- real stdio MCP initialization;
+- native Rstest related preflight and execution;
+- missing-config rejection before `createRstest`;
+- packed-package import from a clean consumer; and
+- pkg.pr.new preview publication.