diff --git a/.changeset/plan-timestamp-prefix.md b/.changeset/plan-timestamp-prefix.md
new file mode 100644
index 00000000000..d757c9686bf
--- /dev/null
+++ b/.changeset/plan-timestamp-prefix.md
@@ -0,0 +1,5 @@
+---
+"@kilocode/cli": patch
+---
+
+Restore session timestamp prefixes for generated plan filenames while preserving descriptive model-chosen names.
diff --git a/packages/opencode/src/kilocode/session/native-plan-prompt.txt b/packages/opencode/src/kilocode/session/native-plan-prompt.txt
index 108154c7392..f6cfdf2ece3 100644
--- a/packages/opencode/src/kilocode/session/native-plan-prompt.txt
+++ b/packages/opencode/src/kilocode/session/native-plan-prompt.txt
@@ -22,7 +22,7 @@ Your job is to gather context, challenge assumptions, resolve design questions,
 
 - You may create and edit plan Markdown files only.
 - Follow the latest Plan File reminder for the target plan location.
-- Prefer `.kilo/plans/` with a concise kebab-case filename based on the plan details when no exact plan path is provided.
+- If no exact plan file path is provided, follow the latest Plan File reminder for the directory and generated filename pattern.
 - Use repo-root `plans/`, `.plans/`, or `.opencode/plans/` only when requested or required by the repo/client and your permissions allow it.
 - Do not write the final plan or call `plan_exit` until the user chooses "Finalize and save the plan".
 - After final approval, write the final plan to the chosen plan file, then call `plan_exit` with the saved plan path.
diff --git a/packages/opencode/src/kilocode/session/prompt.ts b/packages/opencode/src/kilocode/session/prompt.ts
index 7a78d09239f..2200e4089f3 100644
--- a/packages/opencode/src/kilocode/session/prompt.ts
+++ b/packages/opencode/src/kilocode/session/prompt.ts
@@ -287,12 +287,13 @@ export namespace KiloSessionPrompt {
     const file = input.messages ? PlanFile.latest(input.messages) : undefined
     const saved = PlanFile.resolve(file, ctx)
     const target = saved ?? plan
+    const time = input.session.time.created
     const dir = path.dirname(target)
     if (saved && !(await Filesystem.exists(target))) await ensurePlanDir(dir)
 
     const info = saved
       ? `The current saved plan file is ${target}. Read and edit this file when refining the plan.`
-      : `Use the plan path specified by the user or project instructions when present and permissions allow it. If none is specified, create a plan in ${dir} using a concise kebab-case filename based on the plan details.`
+      : `Use any exact plan file path from user or project instructions unchanged. If only a directory is specified, create the plan there; otherwise create it in ${dir}. For generated filenames, use ${time}-<concise-kebab-case-suffix>.md, choosing the suffix from the plan details, for example ${time}-database-cache-plan.md.`
     const body = [
       "## Plan File",
       info,
diff --git a/packages/opencode/test/kilocode/plan-exit-detection.test.ts b/packages/opencode/test/kilocode/plan-exit-detection.test.ts
index a0732f45b68..def09b3bea7 100644
--- a/packages/opencode/test/kilocode/plan-exit-detection.test.ts
+++ b/packages/opencode/test/kilocode/plan-exit-detection.test.ts
@@ -681,9 +681,9 @@ describe("plan_exit detection", () => {
 
       const part = user.parts.at(-1)
       const text = part?.type === "text" ? part.text : ""
-      expect(text).toContain("Use the plan path specified by the user or project instructions")
+      expect(text).toContain(`${session.time.created}-<concise-kebab-case-suffix>.md`)
+      expect(text).toContain(`${session.time.created}-database-cache-plan.md`)
       expect(text).toContain("plans/ or .plans/")
-      expect(text).toContain("If none is specified")
       expect(text).not.toContain(Session.plan(session, Instance.current))
     }))
 
@@ -733,8 +733,7 @@ describe("plan_exit detection", () => {
       const text = content(user)
       expect(text).toContain("The current saved plan file is")
       expect(text.replaceAll(path.sep, "/")).toContain(".plans/fix.md")
-      expect(text).toContain("Read and edit this file when refining the plan")
-      expect(text).toContain("experienced technical leader")
+      expect(text).not.toContain(`${session.time.created}-<concise-kebab-case-suffix>.md`)
       expect(text).not.toContain("No plan file exists yet")
     }))
 
@@ -771,8 +770,7 @@ describe("plan_exit detection", () => {
 
       const part = user.parts.at(-1)
       const text = part?.type === "text" ? part.text : ""
-      expect(text).toContain("Use the plan path specified by the user or project instructions")
-      expect(text).toContain("If none is specified")
+      expect(text).toContain(`${session.time.created}-<concise-kebab-case-suffix>.md`)
       expect(text).toContain("plans/ or .plans/")
       expect(text).not.toContain("Default to")
       expect(text).not.toContain("A fallback plan file exists")