diff --git a/.changeset/react-dist-hotserve.md b/.changeset/react-dist-hotserve.md
new file mode 100644
index 000000000..235fa838f
--- /dev/null
+++ b/.changeset/react-dist-hotserve.md
@@ -0,0 +1,7 @@
+---
+'@conciv/extension-compiler': patch
+---
+
+The vite dev hot-serve remaps a workspace `dist` entry to its `src` sibling and Solid-compiles the TSX it finds there. That remap used to key off a `react/` folder-name convention, which turned `@conciv/mascot/react` into Solid output inside a React host and crashed server rendering with `Comp is not a function`. The decision is now derived from the found source file's nearest `tsconfig.json` (following its `extends` chain): a subtree whose effective `compilerOptions.jsxImportSource` is set to something other than `solid-js`, or whose `compilerOptions.jsx` is `react-jsx`/`react-jsxdev` without a `solid-js` `jsxImportSource`, is classified non-Solid and stays on `dist`. Everything else — an explicit `jsxImportSource: "solid-js"`, or no JSX config in the chain at all (pure-TS subtrees) — keeps the existing remap-to-`src` behavior.
+
+`@conciv/mascot`'s React wrapper subtree carried its JSX config in a sibling file (`tsconfig.react.json` at the package root) rather than in a tsconfig local to `src/react/`, which the nearest-tsconfig directory walk can't discover. It has been relocated to `src/react/tsconfig.json` so the declaration lives with the code it governs; `tsdown.react.config.ts` and the package's `typecheck` script now point at the new path.
diff --git a/packages/extension-compiler/src/conciv-src.ts b/packages/extension-compiler/src/conciv-src.ts
index bd602fda6..15801eb71 100644
--- a/packages/extension-compiler/src/conciv-src.ts
+++ b/packages/extension-compiler/src/conciv-src.ts
@@ -27,6 +27,80 @@ function packageNameFor(dir: string): string | null {
 
 const isConcivName = (name: string) => name.startsWith('@conciv/')
 
+type JsxConfig = {
+  jsx: string | null
+  jsxImportSource: string | null
+}
+
+type RawTsconfig = {
+  jsx: unknown
+  jsxImportSource: unknown
+  extends: unknown
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null
+}
+
+function parseTsconfig(path: string): RawTsconfig | null {
+  try {
+    const parsed: unknown = JSON.parse(readFileSync(path, 'utf8'))
+    if (!isRecord(parsed)) return null
+    const compilerOptions = isRecord(parsed.compilerOptions) ? parsed.compilerOptions : {}
+    return {jsx: compilerOptions.jsx, jsxImportSource: compilerOptions.jsxImportSource, extends: parsed.extends}
+  } catch {
+    return null
+  }
+}
+
+function resolveExtendsPath(fromPath: string, extendsValue: string): string | null {
+  if (!extendsValue.startsWith('.')) return null
+  const joined = join(dirname(fromPath), extendsValue)
+  return joined.endsWith('.json') ? joined : `${joined}.json`
+}
+
+function resolveJsxConfig(path: string, visited: Set<string>): JsxConfig {
+  if (visited.has(path)) return {jsx: null, jsxImportSource: null}
+  visited.add(path)
+  const raw = parseTsconfig(path)
+  if (raw === null) return {jsx: null, jsxImportSource: null}
+  const ownJsx = typeof raw.jsx === 'string' ? raw.jsx : null
+  const ownJsxImportSource = typeof raw.jsxImportSource === 'string' ? raw.jsxImportSource : null
+  if (typeof raw.extends !== 'string') return {jsx: ownJsx, jsxImportSource: ownJsxImportSource}
+  const extendsPath = resolveExtendsPath(path, raw.extends)
+  if (extendsPath === null) return {jsx: ownJsx, jsxImportSource: ownJsxImportSource}
+  const parentConfig = resolveJsxConfig(extendsPath, visited)
+  return {
+    jsx: ownJsx ?? parentConfig.jsx,
+    jsxImportSource: ownJsxImportSource ?? parentConfig.jsxImportSource,
+  }
+}
+
+const tsconfigCache = new Map<string, JsxConfig | null>()
+
+function jsxConfigFor(dir: string): JsxConfig | null {
+  const cached = tsconfigCache.get(dir)
+  if (cached !== undefined) return cached
+  const ownTsconfig = join(dir, 'tsconfig.json')
+  const parent = dirname(dir)
+  const resolved = existsSync(ownTsconfig)
+    ? resolveJsxConfig(ownTsconfig, new Set())
+    : parent === dir
+      ? null
+      : jsxConfigFor(parent)
+  tsconfigCache.set(dir, resolved)
+  return resolved
+}
+
+function isNonSolidJsx(config: JsxConfig | null): boolean {
+  if (config === null) return false
+  if (config.jsxImportSource !== null && config.jsxImportSource !== 'solid-js') return true
+  if ((config.jsx === 'react-jsx' || config.jsx === 'react-jsxdev') && config.jsxImportSource !== 'solid-js') {
+    return true
+  }
+  return false
+}
+
 export function concivSrcEntry(resolvedPath: string): string | null {
   if (resolvedPath.includes('node_modules')) return null
   const extension = ['.jsx', '.js'].find((candidate) => resolvedPath.endsWith(candidate))
@@ -35,7 +109,10 @@ export function concivSrcEntry(resolvedPath: string): string | null {
   if (marker === -1) return null
   const stem = resolvedPath.slice(marker + '/dist/'.length, -extension.length)
   const srcStem = `${resolvedPath.slice(0, marker)}/src/${stem}`
-  return [`${srcStem}.tsx`, `${srcStem}.ts`].find((candidate) => existsSync(candidate)) ?? null
+  const srcCandidate = [`${srcStem}.tsx`, `${srcStem}.ts`].find((candidate) => existsSync(candidate)) ?? null
+  if (srcCandidate === null) return null
+  if (isNonSolidJsx(jsxConfigFor(dirname(srcCandidate)))) return null
+  return srcCandidate
 }
 
 export function isConcivSrcTsx(id: string): boolean {
diff --git a/packages/extension-compiler/test/conciv-src.it.test.ts b/packages/extension-compiler/test/conciv-src.it.test.ts
index 0ff6f0944..c3578e98b 100644
--- a/packages/extension-compiler/test/conciv-src.it.test.ts
+++ b/packages/extension-compiler/test/conciv-src.it.test.ts
@@ -45,6 +45,30 @@ describe('concivSrcEntry', () => {
     expect(concivSrcEntry(fixture('scoped/dist/solid/index.jsx'))).toBe(fixture('scoped/src/solid/index.ts'))
   })
 
+  it('keeps a react-jsx subtree on dist even though a ts source sibling exists, regardless of folder name', () => {
+    expect(concivSrcEntry(fixture('scoped/dist/wrapper/index.js'))).toBeNull()
+  })
+
+  it('keeps a react-jsx subtree on dist even though a tsx source sibling exists, regardless of folder name', () => {
+    expect(concivSrcEntry(fixture('scoped/dist/wrapper/mascot-root.js'))).toBeNull()
+  })
+
+  it('remaps the package root to src even when a sibling subtree carries its own react-jsx tsconfig', () => {
+    expect(concivSrcEntry(fixture('scoped/dist/index.js'))).toBe(fixture('scoped/src/index.tsx'))
+  })
+
+  it('keeps a dist entry on dist when its own tsconfig sets an explicit non-solid jsxImportSource', () => {
+    expect(concivSrcEntry(fixture('scoped/dist/explicit-react/index.js'))).toBeNull()
+  })
+
+  it('remaps a dist entry with no tsconfig of its own and no jsx anywhere in the chain (ts-only package)', () => {
+    expect(concivSrcEntry(fixture('plain/dist/index.js'))).toBe(fixture('plain/src/index.ts'))
+  })
+
+  it('remaps a dist entry whose own tsconfig is empty and inherits jsxImportSource solid-js via extends', () => {
+    expect(concivSrcEntry(fixture('scoped/dist/inherited/index.js'))).toBe(fixture('scoped/src/inherited/index.tsx'))
+  })
+
   it('returns null when no source sibling exists', () => {
     expect(concivSrcEntry(fixture('scoped/dist/nope.js'))).toBeNull()
   })
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/plain/dist/index.js b/packages/extension-compiler/test/fixtures/conciv-src/plain/dist/index.js
new file mode 100644
index 000000000..336ce12bb
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/plain/dist/index.js
@@ -0,0 +1 @@
+export {}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/plain/package.json b/packages/extension-compiler/test/fixtures/conciv-src/plain/package.json
new file mode 100644
index 000000000..ba48380fd
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/plain/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "@conciv/fixture-plain",
+  "type": "module"
+}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/plain/src/index.ts b/packages/extension-compiler/test/fixtures/conciv-src/plain/src/index.ts
new file mode 100644
index 000000000..28b31c7e1
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/plain/src/index.ts
@@ -0,0 +1 @@
+export const plain = {}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/explicit-react/index.js b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/explicit-react/index.js
new file mode 100644
index 000000000..336ce12bb
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/explicit-react/index.js
@@ -0,0 +1 @@
+export {}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/inherited/index.js b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/inherited/index.js
new file mode 100644
index 000000000..336ce12bb
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/inherited/index.js
@@ -0,0 +1 @@
+export {}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/wrapper/index.js b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/wrapper/index.js
new file mode 100644
index 000000000..336ce12bb
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/wrapper/index.js
@@ -0,0 +1 @@
+export {}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/wrapper/mascot-root.js b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/wrapper/mascot-root.js
new file mode 100644
index 000000000..336ce12bb
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/dist/wrapper/mascot-root.js
@@ -0,0 +1 @@
+export {}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/explicit-react/index.tsx b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/explicit-react/index.tsx
new file mode 100644
index 000000000..46ba2b4c8
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/explicit-react/index.tsx
@@ -0,0 +1 @@
+export const ExplicitReact = () => null
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/explicit-react/tsconfig.json b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/explicit-react/tsconfig.json
new file mode 100644
index 000000000..4f9190dd9
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/explicit-react/tsconfig.json
@@ -0,0 +1,5 @@
+{
+  "compilerOptions": {
+    "jsxImportSource": "react"
+  }
+}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/inherited/index.tsx b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/inherited/index.tsx
new file mode 100644
index 000000000..53e9efd9a
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/inherited/index.tsx
@@ -0,0 +1 @@
+export const Inherited = () => <div>ok</div>
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/inherited/tsconfig.json b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/inherited/tsconfig.json
new file mode 100644
index 000000000..4082f16a5
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/inherited/tsconfig.json
@@ -0,0 +1,3 @@
+{
+  "extends": "../../tsconfig.json"
+}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/index.ts b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/index.ts
new file mode 100644
index 000000000..5903dc5ea
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/index.ts
@@ -0,0 +1 @@
+export const Mascot = () => null
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/mascot-root.tsx b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/mascot-root.tsx
new file mode 100644
index 000000000..310bde074
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/mascot-root.tsx
@@ -0,0 +1 @@
+export const MascotRoot = () => null
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/tsconfig.json b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/tsconfig.json
new file mode 100644
index 000000000..a224293f4
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/src/wrapper/tsconfig.json
@@ -0,0 +1,5 @@
+{
+  "compilerOptions": {
+    "jsx": "react-jsx"
+  }
+}
diff --git a/packages/extension-compiler/test/fixtures/conciv-src/scoped/tsconfig.json b/packages/extension-compiler/test/fixtures/conciv-src/scoped/tsconfig.json
new file mode 100644
index 000000000..f33507ab2
--- /dev/null
+++ b/packages/extension-compiler/test/fixtures/conciv-src/scoped/tsconfig.json
@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "jsx": "preserve",
+    "jsxImportSource": "solid-js"
+  }
+}
diff --git a/packages/mascot/package.json b/packages/mascot/package.json
index b1e2b05e9..3e19b61a5 100644
--- a/packages/mascot/package.json
+++ b/packages/mascot/package.json
@@ -105,7 +105,7 @@
   },
   "scripts": {
     "build": "tsdown && tsdown --config tsdown.solid-source.config.ts && tsdown --config tsdown.react.config.ts",
-    "typecheck": "tsc -p tsconfig.json --noEmit && tsc -p tsconfig.react.json --noEmit",
+    "typecheck": "tsc -p tsconfig.json --noEmit && tsc -p src/react/tsconfig.json --noEmit",
     "lint": "oxlint",
     "test": "vitest run --passWithNoTests && playwright test",
     "publint": "publint",
diff --git a/packages/mascot/src/react/tsconfig.json b/packages/mascot/src/react/tsconfig.json
new file mode 100644
index 000000000..b57d3c459
--- /dev/null
+++ b/packages/mascot/src/react/tsconfig.json
@@ -0,0 +1,11 @@
+{
+  "extends": "../../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "../..",
+    "noEmit": true,
+    "lib": ["ES2024", "DOM", "DOM.Iterable"],
+    "jsx": "react-jsx",
+    "types": ["node"]
+  },
+  "include": ["**/*.ts", "**/*.tsx", "../../tests/browser/react-wrapper.browser.test.tsx"]
+}
diff --git a/packages/mascot/tsconfig.react.json b/packages/mascot/tsconfig.react.json
deleted file mode 100644
index 007692810..000000000
--- a/packages/mascot/tsconfig.react.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "extends": "../../tsconfig.base.json",
-  "compilerOptions": {
-    "rootDir": ".",
-    "noEmit": true,
-    "lib": ["ES2024", "DOM", "DOM.Iterable"],
-    "jsx": "react-jsx",
-    "types": ["node"]
-  },
-  "include": ["src/react/**/*.ts", "src/react/**/*.tsx", "tests/browser/react-wrapper.browser.test.tsx"]
-}
diff --git a/packages/mascot/tsdown.react.config.ts b/packages/mascot/tsdown.react.config.ts
index 585c68d58..e93b7bd6e 100644
--- a/packages/mascot/tsdown.react.config.ts
+++ b/packages/mascot/tsdown.react.config.ts
@@ -8,6 +8,6 @@ export default defineConfig({
   unbundle: true,
   dts: true,
   clean: false,
-  tsconfig: 'tsconfig.react.json',
+  tsconfig: 'src/react/tsconfig.json',
   external: ['react', /^react\//, /^react-dom/, /^\.\.\//],
 })