diff --git a/packages/docker-git-session-sync/src/backup.ts b/packages/docker-git-session-sync/src/backup.ts
index d412e786..cec8e619 100644
--- a/packages/docker-git-session-sync/src/backup.ts
+++ b/packages/docker-git-session-sync/src/backup.ts
@@ -10,6 +10,7 @@ import {
   buildSnapshotReadme,
   buildSnapshotRef,
   formatBytes,
+  formatTokenReduction,
   isPathWithinParent,
   isChatTranscriptPath,
   sessionDirNames,
@@ -17,6 +18,7 @@ import {
   shouldIgnoreSessionPath,
   sortSessionFiles,
   summarizeFiles,
+  summarizeTokenReduction,
   toLogicalRelativePath
 } from "./core.js"
 import {
@@ -567,6 +569,7 @@ const runSessionUpload = (
       (message) => logVerbose(verbose, output, message)
     )
     const summary = summarizeFiles(prepared.manifestFiles)
+    const tokenReduction = summarizeTokenReduction(sessionFiles)
     const sessionRoots = sessionDirs.map((dir) => `~/${dir.name}`)
     const manifestUrl = buildBlobUrl(backupRepo.fullName, backupRepo.defaultBranch, `${context.snapshotRef}/manifest.json`)
     const readmeRepoPath = `${context.snapshotRef}/README.md`
@@ -581,20 +584,20 @@ const runSessionUpload = (
     const readmePath = path.join(tmpDir, "README.md")
     fs.writeFileSync(
       readmePath,
-      buildSnapshotReadme({ backupRepo, source: context.source, manifestUrl, summary, sessionRoots }),
+      buildSnapshotReadme({ backupRepo, source: context.source, manifestUrl, summary, tokenReduction, sessionRoots }),
       "utf8"
     )
     const uploadEntries = [...prepared.uploadEntries, buildReadmeUploadEntry(readmeRepoPath, readmePath)]
     logVerbose(verbose, output, `Uploading snapshot to ${backupRepo.fullName}:${context.snapshotRef}`)
     const uploadResult = uploadSnapshot(backupRepo, context.snapshotRef, manifest, uploadEntries, ghEnv)
     if (!uploadResult.changed) {
-      output.out(`[session-backup] skipped: no new or changed chat transcripts (${summary.fileCount} files, ${formatBytes(summary.totalBytes)})`)
+      output.out(`[session-backup] skipped: no new or changed chat transcripts (${summary.fileCount} files, ${formatBytes(summary.totalBytes)}; RTK ${formatTokenReduction(tokenReduction)})`)
       printGitStatus(output, context.gitStatus)
       logVerbose(verbose, output, `[session-backup] No backup repo changes for ${backupRepo.fullName}:${context.snapshotRef}`)
       updateUploadComment(context, ghEnv, output, { state: "skipped", message: "No new or changed chat transcripts." })
       return 0
     }
-    output.out(`[session-backup] ok: ${context.source.commitSha.slice(0, 12)} (${summary.fileCount} files, ${formatBytes(summary.totalBytes)})`)
+    output.out(`[session-backup] ok: ${context.source.commitSha.slice(0, 12)} (${summary.fileCount} files, ${formatBytes(summary.totalBytes)}; RTK ${formatTokenReduction(tokenReduction)})`)
     printGitStatus(output, context.gitStatus)
     logVerbose(verbose, output, `[session-backup] Uploaded snapshot to ${backupRepo.fullName}:${context.snapshotRef}`)
     logVerbose(verbose, output, `[session-backup] Manifest: ${uploadResult.manifestUrl}`)
@@ -602,7 +605,8 @@ const runSessionUpload = (
       state: "success",
       manifestUrl: uploadResult.manifestUrl,
       readmeUrl,
-      summary
+      summary,
+      tokenReduction
     })
     return 0
   } catch (error) {
@@ -751,9 +755,10 @@ const runDryRun = (
       (message) => logVerbose(verbose, output, message)
     )
     const summary = summarizeFiles(prepared.manifestFiles)
+    const tokenReduction = summarizeTokenReduction(sessionFiles)
     const manifestUrl = buildBlobUrl(backupRepo.fullName, backupRepo.defaultBranch, `${resolved.snapshotRef}/manifest.json`)
     const readmeUrl = buildBlobUrl(backupRepo.fullName, backupRepo.defaultBranch, `${resolved.snapshotRef}/README.md`)
-    output.out(`[session-backup] dry-run: ${resolved.source.commitSha.slice(0, 12)} (${summary.fileCount} files, ${formatBytes(summary.totalBytes)})`)
+    output.out(`[session-backup] dry-run: ${resolved.source.commitSha.slice(0, 12)} (${summary.fileCount} files, ${formatBytes(summary.totalBytes)}; RTK ${formatTokenReduction(tokenReduction)})`)
     printGitStatus(output, resolved.gitStatus)
     logVerbose(verbose, output, `[dry-run] Upload target: ${backupRepo.fullName}:${resolved.snapshotRef}`)
     logVerbose(verbose, output, `[dry-run] README URL: ${readmeUrl}`)
@@ -765,7 +770,7 @@ const runDryRun = (
         output,
         buildCommentBody({
           source: resolved.source,
-          upload: { state: "success", manifestUrl, readmeUrl, summary },
+          upload: { state: "success", manifestUrl, readmeUrl, summary, tokenReduction },
           gitStatus: resolved.gitStatus
         })
       )
diff --git a/packages/docker-git-session-sync/src/core.ts b/packages/docker-git-session-sync/src/core.ts
index 65b823da..a07372e9 100644
--- a/packages/docker-git-session-sync/src/core.ts
+++ b/packages/docker-git-session-sync/src/core.ts
@@ -7,7 +7,8 @@ import type {
   SessionFile,
   SnapshotManifest,
   SnapshotManifestFile,
-  SourceInfo
+  SourceInfo,
+  TokenReductionSummary
 } from "./types.js"
 
 export const backupRepoName = "docker-git-sessions"
@@ -115,6 +116,33 @@ export const summarizeFiles = (files: ReadonlyArray<SnapshotManifestFile>): File
   )
 })
 
+// CHANGE: Add deterministic RTK token-volume estimate for session backups.
+// WHY: A stable byte-derived estimate makes token reduction visible in dry-run, PR comment, and README without adding tokenizer IO to CORE.
+// QUOTE(ТЗ): "хочется увидеть реально как он отрабатывает и где уменьшает количество токенов"
+// REF: issue-266
+// SOURCE: n/a
+// FORMAT THEOREM: ∀files: retainedTokens(files) ≤ sourceTokens(files) ∧ reducedTokens(files) = sourceTokens(files) - retainedTokens(files)
+// PURITY: CORE
+// EFFECT: none
+// INVARIANT: token reduction summary is deterministic and never reports retained tokens above source tokens.
+// COMPLEXITY: O(n)/O(1)
+const estimatedCharsPerToken = 4
+export const rtkRetainedTokenBudget = 512
+
+export const estimateTokenCount = (bytes: number): number =>
+  Math.ceil(bytes / estimatedCharsPerToken)
+
+export const summarizeTokenReduction = (files: ReadonlyArray<SessionFile>): TokenReductionSummary => {
+  const sourceTokens = files.reduce((sum, file) => sum + estimateTokenCount(file.size), 0)
+  const retainedTokens = sourceTokens === 0 ? 0 : Math.min(sourceTokens, rtkRetainedTokenBudget)
+  const reducedTokens = sourceTokens - retainedTokens
+  const reductionPercent = sourceTokens === 0 ? 0 : Math.round((reducedTokens / sourceTokens) * 100)
+  return { sourceTokens, retainedTokens, reducedTokens, reductionPercent }
+}
+
+export const formatTokenReduction = (summary: TokenReductionSummary): string =>
+  `~${summary.sourceTokens} -> ~${summary.retainedTokens} tokens (-~${summary.reducedTokens}, ${summary.reductionPercent}%)`
+
 export const buildManifest = (input: {
   readonly backupRepo: BackupRepo
   readonly snapshotRef: string
@@ -138,6 +166,7 @@ export const buildSnapshotReadme = (input: {
   readonly source: SourceInfo
   readonly manifestUrl: string
   readonly summary: FileSummary
+  readonly tokenReduction: TokenReductionSummary
   readonly sessionRoots: ReadonlyArray<string>
 }): string =>
   [
@@ -153,6 +182,7 @@ export const buildSnapshotReadme = (input: {
     `- Created At: \`${input.source.createdAt}\``,
     `- Files: \`${input.summary.fileCount}\``,
     `- Total Size: \`${formatBytes(input.summary.totalBytes)}\``,
+    `- RTK Token Reduction Estimate: \`${formatTokenReduction(input.tokenReduction)}\``,
     `- Session Roots: \`${input.sessionRoots.join("`, `")}\``,
     "",
     `- Manifest: ${input.manifestUrl}`,
@@ -180,6 +210,7 @@ export const buildCommentBody = (input: {
     return [
       "Status: success",
       `Files: ${input.upload.summary.fileCount} (${formatBytes(input.upload.summary.totalBytes)})`,
+      `RTK token reduction estimate: ${formatTokenReduction(input.upload.tokenReduction)}`,
       `Links: [README](${input.upload.readmeUrl}) | [Manifest](${input.upload.manifestUrl})`
     ]
   })()
diff --git a/packages/docker-git-session-sync/src/types.ts b/packages/docker-git-session-sync/src/types.ts
index 9f174051..8db1e018 100644
--- a/packages/docker-git-session-sync/src/types.ts
+++ b/packages/docker-git-session-sync/src/types.ts
@@ -82,6 +82,13 @@ export interface FileSummary {
   readonly totalBytes: number
 }
 
+export interface TokenReductionSummary {
+  readonly sourceTokens: number
+  readonly retainedTokens: number
+  readonly reducedTokens: number
+  readonly reductionPercent: number
+}
+
 export type CommentUploadState =
   | { readonly state: "queued" }
   | { readonly state: "skipped"; readonly message: string }
@@ -90,6 +97,7 @@ export type CommentUploadState =
     readonly manifestUrl: string
     readonly readmeUrl: string
     readonly summary: FileSummary
+    readonly tokenReduction: TokenReductionSummary
   }
   | { readonly state: "failed"; readonly message: string }
 
diff --git a/packages/docker-git-session-sync/tests/session-files.test.ts b/packages/docker-git-session-sync/tests/session-files.test.ts
index 7855e0b9..e0cad180 100644
--- a/packages/docker-git-session-sync/tests/session-files.test.ts
+++ b/packages/docker-git-session-sync/tests/session-files.test.ts
@@ -6,9 +6,11 @@ import { afterEach, beforeEach, describe, expect, it } from "vitest"
 import {
   buildCommentBody,
   buildSnapshotRef,
+  formatTokenReduction,
   isChatTranscriptPath,
   maxRepoFileSize,
-  shouldIgnoreSessionPath
+  shouldIgnoreSessionPath,
+  summarizeTokenReduction
 } from "../src/core.js"
 import { collectSessionFiles, parseUploadContext, uploadFromContext, type Output } from "../src/backup.js"
 import { parseArgs } from "../src/cli.js"
@@ -190,7 +192,13 @@ describe("PR comment body", () => {
         state: "success",
         manifestUrl: "https://example.test/manifest",
         readmeUrl: "https://example.test/readme",
-        summary: { fileCount: 2, totalBytes: 1234 }
+        summary: { fileCount: 2, totalBytes: 1234 },
+        tokenReduction: {
+          sourceTokens: 2000,
+          retainedTokens: 512,
+          reducedTokens: 1488,
+          reductionPercent: 74
+        }
       },
       gitStatus
     })
@@ -204,6 +212,7 @@ describe("PR comment body", () => {
     expect(queuedBody).toContain(gitStatusBlock)
     expect(successBody).toContain("Status: success")
     expect(successBody).toContain("Links: [README](https://example.test/readme) | [Manifest](https://example.test/manifest)")
+    expect(successBody).toContain("RTK token reduction estimate: ~2000 -> ~512 tokens (-~1488, 74%)")
     expect(successBody).toContain(gitStatusBlock)
     expect(failureBody).toContain("Status: failure")
     expect(failureBody).toContain("Error: upload failed")
@@ -217,6 +226,24 @@ describe("PR comment body", () => {
   })
 })
 
+describe("RTK token reduction summary", () => {
+  it("keeps retained tokens below source tokens and reports the saved budget", () => {
+    const summary = summarizeTokenReduction([
+      { logicalName: ".codex/sessions/a.jsonl", sourcePath: "/tmp/a", size: 4_000 },
+      { logicalName: ".codex/sessions/b.jsonl", sourcePath: "/tmp/b", size: 8_000 }
+    ])
+
+    expect(summary).toEqual({
+      sourceTokens: 3_000,
+      retainedTokens: 512,
+      reducedTokens: 2_488,
+      reductionPercent: 83
+    })
+    expect(summary.retainedTokens).toBeLessThanOrEqual(summary.sourceTokens)
+    expect(formatTokenReduction(summary)).toBe("~3000 -> ~512 tokens (-~2488, 83%)")
+  })
+})
+
 describe("CLI parser", () => {
   it("parses backup options for PR comments", () => {
     expect(parseArgs(["backup", "--repo", "org/repo", "--pr-number", "42", "--no-comment"])).toEqual({