diff --git a/.github/workflows/pr-checks.yml b/.github/workflows/pr-checks.yml
index 8a78959..e7d4903 100644
--- a/.github/workflows/pr-checks.yml
+++ b/.github/workflows/pr-checks.yml
@@ -54,7 +54,8 @@ jobs:
           git remote add origin https://github.com/deepseek-ai/deepseek-harness.git
           git fetch --depth 1 -q origin \
             refs/tags/dsh-v0.1.7-rc.2:refs/tags/dsh-v0.1.7-rc.2 \
-            refs/tags/dsh-v0.2.0-rc.2:refs/tags/dsh-v0.2.0-rc.2
+            refs/tags/dsh-v0.2.0-rc.2:refs/tags/dsh-v0.2.0-rc.2 \
+            refs/tags/dsh-v0.2.1-rc.2:refs/tags/dsh-v0.2.1-rc.2
 
       # `pnpm test` is the vitest run only: all three projects (host and client
       # against src, compat against the BUILT plugin at each baseline tag) plus
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 21e47a0..af49280 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -62,7 +62,8 @@ jobs:
           git remote add origin https://github.com/deepseek-ai/deepseek-harness.git
           git fetch --depth 1 -q origin \
             refs/tags/dsh-v0.1.7-rc.2:refs/tags/dsh-v0.1.7-rc.2 \
-            refs/tags/dsh-v0.2.0-rc.2:refs/tags/dsh-v0.2.0-rc.2
+            refs/tags/dsh-v0.2.0-rc.2:refs/tags/dsh-v0.2.0-rc.2 \
+            refs/tags/dsh-v0.2.1-rc.2:refs/tags/dsh-v0.2.1-rc.2
 
       - name: Test
         run: DSH_REPO="$PWD/.tmp/dsh-repo" pnpm test
diff --git a/docs/compatibility.md b/docs/compatibility.md
index 6ffab0e..6fa5a5e 100644
--- a/docs/compatibility.md
+++ b/docs/compatibility.md
@@ -6,13 +6,13 @@ The rules dsh-context must hold on every supported `@deepseek-ai/dsh` release, a
 
 **Law.** Record only what no other artifact carries; delete what code, tests, or git history already say. Verify against the dsh sources before acting — source wins over this page. Less is ALWAYS better.
 
-Last verified: **2026-10-14** (dsh-context `0.70.0`, dsh `0.2.0-rc.2` npm install and `0.2.1-alpha.3` tree).
+Last verified: **2026-10-20** (dsh-context `0.73.3`, dsh `0.1.7-rc.2` / `0.2.0-rc.2` / `0.2.1-rc.2` tag trees).
 
 ## 1 · Supported set
 
 *What the plugin declares it works on.*
 
-1. **Support exactly `0.1.7-rc.2` and `0.2.0-rc.2`** — both the V4 durable-log generation. The floor is `0.1.7-rc.2` because it is the first `0.1.7`-line release with a complete npm dependency closure; anything older gets §2's fallback composition with an upgrade prompt, never a fold.
+1. **Support exactly `0.1.7-rc.2`, `0.2.0-rc.2` and `0.2.1-rc.2`** — all the V4 durable-log generation. The floor is `0.1.7-rc.2` because it is the first `0.1.7`-line release with a complete npm dependency closure; anything older gets §2's fallback composition with an upgrade prompt, never a fold.
 
 ## 2 · Admission
 
diff --git a/package.json b/package.json
index 52996ad..857560e 100644
--- a/package.json
+++ b/package.json
@@ -71,7 +71,8 @@
     "compatibility": {
       "dshReleases": {
         "0.1.7-rc.2": "compatible",
-        "0.2.0-rc.2": "compatible"
+        "0.2.0-rc.2": "compatible",
+        "0.2.1-rc.2": "compatible"
       }
     }
   },
diff --git a/tests/baselines.ts b/tests/baselines.ts
index a4f2aea..1fa4ffa 100644
--- a/tests/baselines.ts
+++ b/tests/baselines.ts
@@ -16,7 +16,7 @@
  */
 
 /** The supported dsh tags, in lockstep with the BASELINES entries below. */
-export type BaselineId = 'v0.1.7-rc.2' | 'v0.2.0-rc.2'
+export type BaselineId = 'v0.1.7-rc.2' | 'v0.2.0-rc.2' | 'v0.2.1-rc.2'
 
 /** The harness web half's client faces, as far as the compat probes consume them. */
 export interface ClientSeam {
@@ -223,12 +223,12 @@ export interface Baseline {
 }
 
 /** One support-matrix entry. Every supported line is the V4 generation, so
- * the seams are spelled once here; a future line that diverges on a needle outgrows the factory (inline its entry instead). */
-function baseline(id: BaselineId, tag: string, session: string): Baseline {
+ * the seams are spelled once here; a line that diverges states its divergence here. */
+function baseline(id: BaselineId, tag: string, session: string, line: { cordis?: string; stockIds?: readonly string[] } = {}): Baseline {
   return {
     id,
     tag,
-    cordis: '4.0.4',
+    cordis: line.cordis ?? '4.0.4',
     session,
     foldEventTypes: [
       'request/header', 'request/context', 'step/start', 'step/end',
@@ -319,7 +319,7 @@ function baseline(id: BaselineId, tag: string, session: string): Baseline {
       },
       stockIds: {
         file: 'packages/bundle/base/cordis.patch.yml',
-        ids: ['llm-deepseek', 'web-search-deepseek'],
+        ids: line.stockIds ?? ['llm-deepseek', 'web-search-deepseek'],
       },
       providerFiles: [
         {
@@ -384,4 +384,12 @@ export const BASELINES: readonly Baseline[] = [
   // session-format tree carries no v4-to-v5 migration). Cordis stays 4.0.4,
   // and the line continues to enforce the plugin dsh-peer gate this plugin's `>=0.1.7-rc.2` peers satisfy.
   baseline('v0.2.0-rc.2', 'dsh-v0.2.0-rc.2', '0.2.0-rc.2'),
+  // The 0.2.1 line continues the V4 Config-form generation with every seam the
+  // plugin rides spelled as at `0.2.0-rc.2`. Two facts differ: the line
+  // vendors cordis 4.0.5, and it adds the `web-deepseek-api` entry the
+  // balance fold falls back to.
+  baseline('v0.2.1-rc.2', 'dsh-v0.2.1-rc.2', '0.2.1-rc.2', {
+    cordis: '4.0.5',
+    stockIds: ['llm-deepseek', 'web-search-deepseek', 'web-deepseek-api'],
+  }),
 ]
diff --git a/tests/compat/staging.ts b/tests/compat/staging.ts
index d21bc2a..fdb6d01 100644
--- a/tests/compat/staging.ts
+++ b/tests/compat/staging.ts
@@ -57,6 +57,16 @@ export function stageFile(baseline: Baseline, tagPath: string, localName: string
   return file
 }
 
+/** Stage one file only when the tag carries it: a line that does not ship the
+ * file stages nothing, and the sibling a staged module imports by relative
+ * path rides along. */
+function stageFileIfPresent(baseline: Baseline, tagPath: string, localName: string): boolean {
+  const run = spawnSync('git', ['-C', DSH_REPO, 'cat-file', '-e', `${baseline.tag}:${tagPath}`], { encoding: 'utf8' })
+  if (run.status !== 0) return false
+  stageFile(baseline, tagPath, localName)
+  return true
+}
+
 /** The host packages the tag's staged sources import at runtime, at this line's own versions. */
 function hostDepsOf(baseline: Baseline): Record<string, string> {
   return {
@@ -108,7 +118,7 @@ function driverSource(pluginUrl: string, developerMessages: boolean): string {
   return `
 import { Context } from '@deepseek-ai/cordis'
 import { SessionProjectionRegistry } from './registry/index.ts'
-import { snapshotJsonValue } from './dsh/json-values.ts'
+import { snapshotJsonValue } from './dsh/index.ts'
 const plugin = await import(${JSON.stringify(pluginUrl)})
 const ctx = new Context()
 const registry = new SessionProjectionRegistry(ctx)
@@ -268,7 +278,12 @@ export function runDriver(baseline: Baseline): DriverReport {
   ensureHostDeps(baseline)
   stageFile(baseline, 'packages/session/session-projection/src/index.ts', join('registry', 'index.ts'))
   stageFile(baseline, 'packages/session/session-projection/src/types.ts', join('registry', 'types.ts'))
-  stageFile(baseline, 'packages/util/values/src/index.ts', join('dsh', 'json-values.ts'))
+  // The values package under its own file name: its modules import each other
+  // by relative path, so renaming the entry would break the sibling links.
+  stageFile(baseline, 'packages/util/values/src/index.ts', join('dsh', 'index.ts'))
+  // The 0.2.1 line's values package grew a sibling module the staged entry
+  // re-exports by relative path, so it rides along where the tag ships it.
+  stageFileIfPresent(baseline, 'packages/util/values/src/partial-json.ts', join('dsh', 'partial-json.ts'))
   const driver = join(STAGE, baseline.id, 'driver.mjs')
   writeFileSync(driver, driverSource(`file://${join(REPO, 'lib', 'index.js')}`, baseline.foldEventTypes.includes('developer/message')))
   const run = spawnSync(process.execPath, [driver], { cwd: STAGE, encoding: 'utf8', timeout: 60_000 })