diff --git a/client/src/lib/version.ts b/client/src/lib/version.ts
index 255bea41..be1ae1ad 100644
--- a/client/src/lib/version.ts
+++ b/client/src/lib/version.ts
@@ -9,7 +9,7 @@
  * Update this file with every code change / git commit.
  */
 
-export const APP_VERSION = "0.27.15";
+export const APP_VERSION = "0.27.16";
 
 export interface ReleaseNote {
   version: string;
@@ -18,6 +18,13 @@ export interface ReleaseNote {
 }
 
 export const RELEASE_NOTES: ReleaseNote[] = [
+  {
+    version: "0.27.16",
+    date: "2026-03-20",
+    changes: [
+      "Increase document limit to 250K characters — write instruction, context builder, and analysis endpoints all support much larger documents",
+    ],
+  },
   {
     version: "0.27.15",
     date: "2026-03-13",
diff --git a/server/context-builder.ts b/server/context-builder.ts
index cc30361c..aa8a40bd 100644
--- a/server/context-builder.ts
+++ b/server/context-builder.ts
@@ -45,10 +45,10 @@ export {
 
 /** Default truncation limits — one place to change them */
 export const LIMITS = {
-  document: 8000,
-  documentShort: 6000,
-  documentBrief: 2000,
-  documentFull: 50000,
+  document: 250_000,
+  documentShort: 100_000,
+  documentBrief: 20_000,
+  documentFull: 250_000,
   reference: 500,
   wireframe: 3000,
   historyEntries: 5,
diff --git a/server/routes.ts b/server/routes.ts
index 64c2ade8..078d3f8f 100644
--- a/server/routes.ts
+++ b/server/routes.ts
@@ -953,7 +953,7 @@ You MUST respond with ONLY valid JSON in this exact format (no markdown, no expl
       const challengeAppConfig = getAppTypeConfig(challengeAppType);
       const challengeAppContext = formatAppTypeContext(challengeAppType);
 
-      const MAX_ANALYSIS_LENGTH = 8000;
+      const MAX_ANALYSIS_LENGTH = 250_000;
       const analysisText = docText.slice(0, MAX_ANALYSIS_LENGTH);
 
       // Resolve personas — use effective (DB override + code default), fall back to built-in
@@ -1144,7 +1144,7 @@ Output only valid JSON, no markdown.`,
       const appConfig = getAppTypeConfig(appType);
       const appContext = formatAppTypeContext(appType);
 
-      const MAX_ANALYSIS_LENGTH = 6000;
+      const MAX_ANALYSIS_LENGTH = 250_000;
       const analysisText = docText.slice(0, MAX_ANALYSIS_LENGTH);
 
       // Build discussion history context if available
@@ -4374,7 +4374,7 @@ ${docText ? `CURRENT DOCUMENT:\n${docText.slice(0, 3000)}\n\n` : ""}INTERVIEW Q&
       const askAppConfig = getAppTypeConfig(askAppType);
       const askAppContext = formatAppTypeContext(askAppType);
 
-      const MAX_DOC_LENGTH = 6000;
+      const MAX_DOC_LENGTH = 250_000;
       const analysisText = docText.slice(0, MAX_DOC_LENGTH);
 
       // Build session context section from pinned documents / captured items
diff --git a/shared/schema.ts b/shared/schema.ts
index 4cdf18d7..efeedfc8 100644
--- a/shared/schema.ts
+++ b/shared/schema.ts
@@ -335,7 +335,7 @@ export const writeRequestSchema = z.object({
   selectedText: z.string().max(50_000).optional(),
 
   // Intent (required - what user wants)
-  instruction: z.string().min(1, "Instruction is required").max(5_000),
+  instruction: z.string().min(1, "Instruction is required").max(250_000),
 
   // Context (optional - additional grounding)
   provocation: provocationContextSchema.optional(),
diff --git a/tests/unit/server/context-builder.test.ts b/tests/unit/server/context-builder.test.ts
index 7122803a..7a9576ee 100644
--- a/tests/unit/server/context-builder.test.ts
+++ b/tests/unit/server/context-builder.test.ts
@@ -343,10 +343,10 @@ describe("buildContext", () => {
 // ---------------------------------------------------------------------------
 describe("LIMITS", () => {
   it("has expected defaults", () => {
-    expect(LIMITS.document).toBe(8000);
-    expect(LIMITS.documentShort).toBe(6000);
-    expect(LIMITS.documentBrief).toBe(2000);
-    expect(LIMITS.documentFull).toBe(50000);
+    expect(LIMITS.document).toBe(250_000);
+    expect(LIMITS.documentShort).toBe(100_000);
+    expect(LIMITS.documentBrief).toBe(20_000);
+    expect(LIMITS.documentFull).toBe(250_000);
     expect(LIMITS.reference).toBe(500);
     expect(LIMITS.wireframe).toBe(3000);
     expect(LIMITS.historyEntries).toBe(5);