diff --git a/packages/runtime-playground/src/editor-command-runners.ts b/packages/runtime-playground/src/editor-command-runners.ts
index a1f42601..fbf68f2a 100644
--- a/packages/runtime-playground/src/editor-command-runners.ts
+++ b/packages/runtime-playground/src/editor-command-runners.ts
@@ -630,7 +630,7 @@ export async function runEditorOpenCommand({
       const waitStartedAt = now()
       const waitStartedAtMs = Date.now()
       try {
-        const readiness = await waitForEditorOpenReadiness(page, target.waitSelector, waitTimeoutMs)
+        const readiness = await waitForEditorOpenReadiness(page, target, target.waitSelector, waitTimeoutMs)
         editorReadiness = readiness.editorReadiness
         editorCanvasReadiness = readiness.editorCanvasReadiness
         finalUrl = page.url()
@@ -812,8 +812,8 @@ export function editorOpenArtifactFilesForCapture(capture: ReadonlySet<string>,
   }
 }
 
-export async function waitForEditorOpenReadiness(page: import("playwright").Page, waitSelector: string | undefined, timeoutMs: number): Promise<{ editorReadiness: BrowserEditorReadinessSummary; editorCanvasReadiness?: BrowserEditorCanvasProbeSummary }> {
-  const editorReadiness = await waitForEditorSemanticReadiness(page, timeoutMs)
+export async function waitForEditorOpenReadiness(page: import("playwright").Page, target: EditorOpenTarget, waitSelector: string | undefined, timeoutMs: number): Promise<{ editorReadiness: BrowserEditorReadinessSummary; editorCanvasReadiness?: BrowserEditorCanvasProbeSummary }> {
+  const editorReadiness = await waitForEditorSemanticReadiness(page, target, timeoutMs)
   if (!waitSelector) {
     return { editorReadiness }
   }
@@ -1781,8 +1781,8 @@ async function waitForEditorReadiness(page: import("playwright").Page, timeoutMs
 
 // Opening and validating an editor require the block-editor data store. Global
 // block APIs and save availability are stricter, separate capabilities.
-async function waitForEditorSemanticReadiness(page: import("playwright").Page, timeoutMs: number): Promise<BrowserEditorReadinessSummary> {
-  return page.waitForFunction(() => {
+async function waitForEditorSemanticReadiness(page: import("playwright").Page, target: EditorOpenTarget, timeoutMs: number): Promise<BrowserEditorReadinessSummary> {
+  return page.waitForFunction((expectedPostId) => {
     const win = window as unknown as {
       wp?: {
         blocks?: { parse?: unknown; getBlockTypes?: () => unknown[] }
@@ -1804,16 +1804,20 @@ async function waitForEditorSemanticReadiness(page: import("playwright").Page, t
     const dispatch = win.wp?.data?.dispatch
     const editor = select("core/editor")
     const editorDispatch = typeof dispatch === "function" ? dispatch("core/editor") : undefined
+    const postId = typeof editor?.getCurrentPostId === "function" ? editor.getCurrentPostId() : undefined
+    if (expectedPostId !== null && Number(postId) !== expectedPostId) {
+      return false
+    }
     return {
       schema: "wp-codebox/editor-readiness/v1",
       status: "ready",
       storesAvailable: Boolean(editor && blockEditor),
       canSave: typeof editorDispatch?.savePost === "function",
       ...(Array.isArray(blockTypes) ? { blockTypesRegistered: blockTypes.length } : {}),
-      postId: typeof editor?.getCurrentPostId === "function" ? editor.getCurrentPostId() : undefined,
+      postId,
       postType: typeof editor?.getCurrentPostType === "function" ? editor.getCurrentPostType() : undefined,
     }
-  }, undefined, { timeout: timeoutMs }).then(async (handle) => {
+  }, target.kind === "post" && target.postId ? target.postId : null, { timeout: timeoutMs }).then(async (handle) => {
     const readiness = await handle.jsonValue() as BrowserEditorReadinessSummary | false
     if (!readiness) {
       throw new Error("wp-codebox-editor-readiness-timeout: Gutenberg block runtime did not become available")
diff --git a/tests/browser-routed-command-security.test.ts b/tests/browser-routed-command-security.test.ts
index 3f5bdb4e..081b13d0 100644
--- a/tests/browser-routed-command-security.test.ts
+++ b/tests/browser-routed-command-security.test.ts
@@ -24,6 +24,7 @@ const PARENT_CANVAS_PRESENTATION_IDENTITY = "f".repeat(64)
 const SLOW_PRESENTATION_IDENTITY = "1".repeat(64)
 const PENDING_STYLES_PRESENTATION_IDENTITY = "2".repeat(64)
 const GROWING_PRESENTATION_IDENTITIES = ["3".repeat(64), "4".repeat(64)]
+const DELAYED_POST_PRESENTATION_IDENTITY = "5".repeat(64)
 const matchedPresentationMarkup = `<style>html,body{margin:0}.block-editor-block-list__layout{box-sizing:border-box;width:200px;height:400px;background:linear-gradient(#123,#abc);color:white;padding:12px}</style><div class="block-editor-block-list__layout">Matched presentation</div>`
 const editorShell = `<!doctype html><script>
 globalThis.__name = (value) => value
@@ -49,13 +50,16 @@ const replacingCanvasEditorHtml = `${editorShell}<iframe name="editor-canvas" sr
 const delayedCanvasEditorHtml = `${editorShell}<div class="block-editor-block-list__layout"><div class="block-editor-block-list__block" data-block="transition">Transition</div></div><script>setTimeout(() => { const iframe = document.createElement('iframe'); iframe.name = 'editor-canvas'; iframe.srcdoc = '<style>/* blocks-engine-presentation:${DELAYED_CANVAS_PRESENTATION_IDENTITY} */<\\/style>'; document.body.append(iframe) }, 300)</script>`
 const slowPresentationEditorHtml = `${editorShell}<iframe name="editor-canvas" srcdoc="<script>setTimeout(() => { const style = document.createElement('style'); style.textContent = '/* blocks-engine-presentation:${SLOW_PRESENTATION_IDENTITY} */'; document.head.append(style) }, 3500)<\/script><div class='block-editor-block-list__layout'><div class='block-editor-block-list__block' data-block='slow'>Slow</div></div>"></iframe>`
 const pendingStylesEditorHtml = `${editorShell}<iframe name="editor-canvas" srcdoc="<link rel='stylesheet' href='http://127.0.0.1:9/unavailable.css'><style>/* blocks-engine-presentation:${PENDING_STYLES_PRESENTATION_IDENTITY} */<\/style><div class='block-editor-block-list__layout'><div class='block-editor-block-list__block' data-block='pending'>Pending</div></div>"></iframe>`
+const delayedPostEditorHtml = `${editorShell}<script>const fixtureSelect = wp.data.select; let currentPostId = null; wp.data.select = (store) => store === 'core/editor' ? { getCurrentPostId: () => currentPostId, getCurrentPostType: () => currentPostId ? 'page' : null } : fixtureSelect(store); setTimeout(() => { currentPostId = 4; const iframe = document.createElement('iframe'); iframe.name = 'editor-canvas'; iframe.srcdoc = "<style>/* blocks-engine-presentation:${DELAYED_POST_PRESENTATION_IDENTITY} */<\\/style><div class='block-editor-block-list__layout'>Hydrated post</div>"; document.body.append(iframe) }, 1500)<\/script>`
 const growingPresentationEditorHtml = `${editorShell}<iframe name="editor-canvas" srcdoc="<style>/* blocks-engine-presentation:${GROWING_PRESENTATION_IDENTITIES[0]} */<\/style><script>let identity = 0; setInterval(() => { const style = document.createElement('style'); style.textContent = '/* blocks-engine-presentation:' + (identity++).toString(16).padStart(64, '9') + ' */'; document.head.append(style) }, 100); setTimeout(() => { const style = document.createElement('style'); style.textContent = '/* blocks-engine-presentation:${GROWING_PRESENTATION_IDENTITIES[1]} */'; document.head.append(style) }, 4100)<\/script><div class='block-editor-block-list__layout'><div class='block-editor-block-list__block' data-block='growing'>Growing</div></div>"></iframe>`
 
 test("real browser commands sanitize console, artifacts, stdout, and failure stderr", async () => {
   const httpServer = createServer((request, response) => {
     response.setHeader("content-type", "text/html")
-    response.end(request.url?.startsWith("/wp-admin/post.php")
-      ? growingPresentationEditorHtml
+    response.end(request.url?.includes("post=4")
+      ? delayedPostEditorHtml
+      : request.url?.startsWith("/wp-admin/post.php")
+        ? growingPresentationEditorHtml
       : request.url?.startsWith("/broken")
       ? "<main>Broken editor fixture</main>"
       : request.url?.startsWith("/presentation")
@@ -248,6 +252,24 @@ test("real browser commands sanitize console, artifacts, stdout, and failure std
       assert.deepEqual(output.summary.editorPresentation.generatedPresentationIdentities, [PENDING_STYLES_PRESENTATION_IDENTITY])
     })
 
+    await withTempDir("wp-codebox-real-editor-delayed-post-readiness-", async (artifactRoot) => {
+      const result = await runEditorOpenCommand({
+        artifactRoot,
+        runPlaygroundCommand: async (command) => ({
+          text: command.includes("capture-presentation-contract")
+            ? JSON.stringify({ identities: [DELAYED_POST_PRESENTATION_IDENTITY], complete: true })
+            : "[]",
+          exitCode: 0,
+        }),
+        runtimeSpec,
+        server,
+        spec: { command: "wordpress.editor-open", args: ["post-id=4", "post-type=page", "capture=steps", "wait-timeout=5s"] },
+      })
+      const output = JSON.parse(result.output) as { summary: { editorReadiness: { postId: number }; editorPresentation: { generatedPresentationIdentities: string[] } } }
+      assert.equal(output.summary.editorReadiness.postId, 4)
+      assert.deepEqual(output.summary.editorPresentation.generatedPresentationIdentities, [DELAYED_POST_PRESENTATION_IDENTITY])
+    })
+
     await withTempDir("wp-codebox-real-editor-growing-presentation-security-", async (artifactRoot) => {
       const result = await runEditorOpenCommand({
         artifactRoot,
diff --git a/tests/editor-actions.test.ts b/tests/editor-actions.test.ts
index 7dff3996..98054d79 100644
--- a/tests/editor-actions.test.ts
+++ b/tests/editor-actions.test.ts
@@ -461,7 +461,7 @@ const semanticReadyPage = {
       },
     }
     try {
-      const readiness = predicate()
+      const readiness = predicate(selector)
       assert.ok(readiness)
       return { jsonValue: async () => readiness }
     } finally {
@@ -469,15 +469,16 @@ const semanticReadyPage = {
     }
   },
 } as never
-const semanticReadiness = await waitForEditorOpenReadiness(semanticReadyPage, undefined, 1)
+const genericEditorTarget = { kind: "url", url: "/wp-admin/site-editor.php" } as const
+const semanticReadiness = await waitForEditorOpenReadiness(semanticReadyPage, genericEditorTarget, undefined, 1)
 assert.equal(semanticReadiness.editorReadiness.blockTypesRegistered, undefined)
 assert.equal(semanticReadiness.editorReadiness.storesAvailable, false)
 assert.equal(semanticReadiness.editorReadiness.canSave, false)
 await assert.rejects(
-  () => waitForEditorOpenReadiness(semanticReadyPage, ".legacy-editor-shell", 1),
+  () => waitForEditorOpenReadiness(semanticReadyPage, genericEditorTarget, ".legacy-editor-shell", 1),
   /Timed out waiting for \.legacy-editor-shell/,
 )
-assert.deepEqual(readinessCalls, [undefined, undefined, ".legacy-editor-shell"])
+assert.deepEqual(readinessCalls, [null, null, ".legacy-editor-shell"])
 
 const retainedArtifact = {
   artifactType: "editor-open",