diff --git a/docs/benchmarks.md b/docs/benchmarks.md
index 040b42a..0f8fed6 100644
--- a/docs/benchmarks.md
+++ b/docs/benchmarks.md
@@ -45,6 +45,29 @@ Example shape:
 
 The numbers above illustrate the JSON schema only; they are not Rivet performance claims or release thresholds.
 
+## Measuring a packaged app
+
+`raco rivet measure` reports what a host app actually weighs, so release CI
+can gate budgets instead of eyeballing dist listings:
+
+- `raco rivet measure size` lists every artifact in `dist/` with its byte
+  count. With `--budget <file>`, each artifact is matched against the
+  budget file's rules — `{"rules": [{"glob": "*.dmg", "max-bytes":
+  100000000}, ...]}`, first matching glob wins — and the command exits
+  nonzero when any artifact exceeds its budget, so a bundle-size regression
+  fails the build instead of shipping. `--artifact <name>` narrows the
+  report to one file.
+- `raco rivet measure startup [--artifact <name>] [--seconds N]` runs the
+  launch-survival smoke (the same gate `raco rivet package` and `verify`
+  use) and reports the elapsed window, so the artifact's ability to boot on
+  the packaging machine is measured rather than assumed.
+
+Per-RPC latency stays with the integration benchmarks above: the
+`--benchmark` mode measures the real embedded runtime end to end, which a
+detached CLI cannot reach into a packaged GUI host. A practical release
+budget file lives in the product repository next to `rivet-schema.json` and
+is updated in the same review that changes packaging.
+
 ## CI behavior
 
 Every `Embedded Roundtrip` job first runs the existing correctness integration path, then starts a fresh integration process with `--benchmark`. The second step records one JSON report for that runner and revision. Starting a fresh process is important because the embedded Racket runtime is intentionally one-shot within a process and startup is itself one of the measured costs.
diff --git a/rivet-cli/main.rkt b/rivet-cli/main.rkt
index 2ea0d93..8e50e79 100644
--- a/rivet-cli/main.rkt
+++ b/rivet-cli/main.rkt
@@ -64,6 +64,8 @@
     "                           [--published-at <ts>] [--rollout <0-100>] [--rollback-allowed]\n"
     "                                      compose a verified family update manifest\n"
     "  raco rivet i18n                    verify shared/i18n parity and regenerate embedded tables\n"
+    "  raco rivet measure                 report packaged artifact sizes and launch survival\n"
+    "  raco rivet measure size --budget <file>  fail when artifacts exceed budgets\n"
     "  raco rivet compliance              generate SBOM/notices and run the license audit\n"
     "  raco rivet verify                  re-verify the current packaged artifact\n"
     "  raco rivet verify --production     verify production trust/notarization requirements\n"
@@ -295,6 +297,11 @@
      (define-values (keys files) (apply values (generate-i18n! (current-project!))))
      (say "i18n: ~a keys across zh/en; wrote ~a embedded table~a"
           keys files (if (= files 1) "" "s"))]
+    [(cons "measure" measure-args)
+     ;; Report packaged-app measurements (issue #262): dist artifact sizes
+     ;; against optional budgets, and the launch-survival window.
+     (define run-measure (command "measure" 'run-measure))
+     (run-measure measure-args)]
     [(list "compliance")
      (define generate-compliance-artifacts!
        (command "compliance" 'generate-compliance-artifacts!))
diff --git a/rivet-cli/measure.rkt b/rivet-cli/measure.rkt
new file mode 100644
index 0000000..bcb3eb3
--- /dev/null
+++ b/rivet-cli/measure.rkt
@@ -0,0 +1,196 @@
+#lang racket/base
+
+;; Measurement for host apps (issue #262). The migration docs defined stop
+;; rules referencing startup/package-size/latency thresholds, so release CI
+;; needs one command that reports what a packaged app actually weighs and
+;; whether it still fits its budgets. Size is fully deterministic here;
+;; startup wraps the launch-smoke survival window; per-RPC latency stays
+;; with the integration benchmarks (docs/benchmarks.md --benchmark mode),
+;; which already measure the real embedded runtime end to end.
+
+(require file/glob
+         json
+         racket/file
+         racket/list
+         racket/format
+         racket/match
+         racket/path
+         racket/string
+         "launch-smoke.rkt"
+         "project.rkt")
+
+(provide measure-size
+         measure-startup
+         parse-budget-file)
+
+(define dist-directory "dist")
+
+(define (dist-artifacts root)
+  (define dist (build-path root dist-directory))
+  (if (directory-exists? dist)
+      (sort
+       (for/list ([path (in-list (directory-list dist #:build? #t))]
+                  #:when (file-exists? path))
+         path)
+       #:key path->string
+       string<?)
+      '()))
+
+(define (format-bytes count)
+  (define mb (/ count 1024.0 1024.0))
+  (if (>= mb 1.0)
+      (format "~a (~a MiB)" count (~r mb #:precision 1))
+      (format "~a bytes" count)))
+
+;; Budget files are JSON: {"rules": [{"glob": "*.dmg", "max-bytes":
+;; 100000000}, ...]}. The first matching rule wins, so list the most
+;; specific glob first.
+(define (parse-budget-file path)
+  (unless (file-exists? path)
+    (error 'measure "budget file ~a does not exist" path))
+  (define document
+    (with-handlers ([exn:fail?
+                     (lambda (e)
+                       (error 'measure "budget file ~a is not valid JSON: ~a"
+                              path (exn-message e)))])
+      (call-with-input-file path read-json)))
+  (define rules (hash-ref document 'rules (lambda () #f)))
+  (unless (and (list? rules)
+               (for/and ([rule (in-list rules)])
+                 (and (hash? rule)
+                      (string? (hash-ref rule 'glob (lambda () #f)))
+                      (exact-positive-integer?
+                       (hash-ref rule 'max-bytes (lambda () #f))))))
+    (error 'measure
+           "budget file ~a must contain {\"rules\": [{\"glob\": ..., \"max-bytes\": ...}, ...]}"
+           path))
+  rules)
+
+(define (budget-for rules artifact)
+  (define name (path->string (file-name-from-path artifact)))
+  (for/first ([rule (in-list rules)]
+              #:when (glob-match? (hash-ref rule 'glob) name))
+    (hash-ref rule 'max-bytes)))
+
+(define (measure-size project
+                      #:budget-path [budget-path #f]
+                      #:artifact [artifact-filter #f])
+  (define root (rivet-project-root project))
+  (define artifacts
+    (if artifact-filter
+        (filter (lambda (path)
+                  (equal? (path->string (file-name-from-path path))
+                          artifact-filter))
+                (dist-artifacts root))
+        (dist-artifacts root)))
+  (when (null? artifacts)
+    (error 'measure
+           "no packaged artifacts under ~a; run `raco rivet package` or `raco rivet release` first"
+           (build-path root dist-directory)))
+  (define rules (and budget-path (parse-budget-file budget-path)))
+  (define violations '())
+  (define rows
+    (for/list ([artifact (in-list artifacts)])
+      (define bytes (file-size artifact))
+      (define budget (and rules (budget-for rules artifact)))
+      (when (and budget (> bytes budget))
+        (set! violations
+              (cons (cons artifact (cons bytes budget)) violations)))
+      (hash 'name (path->string (file-name-from-path artifact))
+            'bytes bytes
+            'budget-bytes budget)))
+  (hash 'artifacts (reverse rows)
+        'violations (reverse violations)))
+
+(define (display-size-report report)
+  (for ([row (in-list (hash-ref report 'artifacts))])
+    (define budget (hash-ref row 'budget-bytes))
+    (printf "  ~a: ~a~a\n"
+            (hash-ref row 'name)
+            (format-bytes (hash-ref row 'bytes))
+            (if budget
+                (format " [budget ~a]" (format-bytes budget))
+                "")))
+  (for ([violation (in-list (hash-ref report 'violations))])
+    (define artifact (car violation))
+    (define bytes (car (cdr violation)))
+    (define budget (cdr (cdr violation)))
+    (printf "  OVER BUDGET: ~a is ~a against a ~a budget\n"
+            (path->string (file-name-from-path artifact))
+            (format-bytes bytes)
+            (format-bytes budget))))
+
+(define (measure-startup project
+                         #:artifact [artifact-filter #f]
+                         #:seconds [seconds 5.0])
+  (define root (rivet-project-root project))
+  (define artifacts
+    (if artifact-filter
+        (filter (lambda (path)
+                  (equal? (path->string (file-name-from-path path))
+                          artifact-filter))
+                (dist-artifacts root))
+        (dist-artifacts root)))
+  (when (null? artifacts)
+    (error 'measure
+           "no packaged artifacts under ~a; run `raco rivet package` first"
+           (build-path root dist-directory)))
+  ;; The most recent packaged GUI artifact is the smoke subject; dist keeps
+  ;; manifests and SBOMs too, so pick the largest executable-like file.
+  (define artifact
+    (argmax file-size
+            (filter (lambda (path)
+                      (not (regexp-match? #rx"[.](json|txt|sha256|sig|zip)$"
+                                          (path->string path))))
+                    artifacts)))
+  (define started (current-inexact-milliseconds))
+  (launch-smoke! artifact
+                 #:seconds seconds
+                 #:who 'measure-startup)
+  (define elapsed (/ (- (current-inexact-milliseconds) started) 1000.0))
+  (hash 'artifact (path->string (file-name-from-path artifact))
+        'survival-seconds elapsed
+        'required-seconds seconds))
+
+(define (display-startup-report report)
+  (printf "  ~a survived its ~a second launch window (~a elapsed)\n"
+          (hash-ref report 'artifact)
+          (hash-ref report 'required-seconds)
+          (~r (hash-ref report 'survival-seconds) #:precision 2)))
+
+(define (run-measure args)
+  (define find-project
+    (dynamic-require "project.rkt" 'find-project))
+  (define project
+    (or (find-project)
+        (error 'rivet "no rivet.rktd found in this directory or its parents")))
+  (match args
+    [(list "size")
+     (define report (measure-size project))
+     (display-size-report report)
+     (unless (null? (hash-ref report 'violations))
+       (error 'measure "size budgets exceeded; see the OVER BUDGET lines above"))]
+    [(list "size" "--budget" budget-path)
+     (define report (measure-size project #:budget-path budget-path))
+     (display-size-report report)
+     (unless (null? (hash-ref report 'violations))
+       (error 'measure "size budgets exceeded; see the OVER BUDGET lines above"))]
+    [(list "size" "--artifact" artifact)
+     (display-size-report (measure-size project #:artifact artifact))]
+    [(list "startup")
+     (display-startup-report (measure-startup project))]
+    [(list "startup" "--artifact" artifact)
+     (display-startup-report (measure-startup project #:artifact artifact))]
+    [(list "startup" "--seconds" seconds-text)
+     (define seconds
+       (with-handlers ([exn:fail? (lambda (_) #f)])
+         (string->number seconds-text)))
+     (unless (and (real? seconds) (positive? seconds))
+       (error 'measure "--seconds requires a positive number"))
+     (display-startup-report (measure-startup project #:seconds seconds))]
+    [_
+     (error 'measure
+            "unknown measurement ~a; use `size [--budget <file>] [--artifact <name>]` or `startup [--artifact <name>] [--seconds N]`"
+            (string-join (if (null? args) '("(none)") args) " "))]))
+
+(provide run-measure)
diff --git a/rivet/tests/measure.rkt b/rivet/tests/measure.rkt
new file mode 100644
index 0000000..052e046
--- /dev/null
+++ b/rivet/tests/measure.rkt
@@ -0,0 +1,100 @@
+#lang racket/base
+
+(require json
+         racket/file
+         racket/port
+         racket/string
+         rackunit
+         "../../rivet-cli/measure.rkt"
+         "../../rivet-cli/project.rkt"
+         "../../rivet-cli/scaffold.rkt")
+
+;; The measurement surface is the dist/ tree, so the fixtures are plain
+;; files standing in for packaged artifacts — no native packaging needed.
+
+(define temp-root (make-temporary-file "rivet-measure-~a" 'directory))
+(dynamic-wind
+  void
+  (lambda ()
+    (define project-root (create-project! "measured" temp-root))
+    (define project (load-project project-root))
+    (define dist (build-path project-root "dist"))
+    (make-directory* dist)
+    (define (stage-artifact name bytes)
+      (call-with-output-file (build-path dist name)
+        (lambda (out) (write-bytes (make-bytes bytes 65) out))))
+    (stage-artifact "measured-0.1.0-macos.dmg" 3000)
+    (stage-artifact "measured-0.1.0-macos-arm64.zip" 1500)
+    (stage-artifact "update-stable.json" 40)
+
+    ;; No budgets: every artifact is listed with its byte count and no
+    ;; violations exist.
+    (define plain (measure-size project))
+    (check-equal? (length (hash-ref plain 'artifacts)) 3)
+    (check-equal? (hash-ref plain 'violations) '())
+    (check-true
+     (for/and ([row (in-list (hash-ref plain 'artifacts))])
+       (and (exact-positive-integer? (hash-ref row 'bytes))
+            (not (hash-ref row 'budget-bytes)))))
+
+    ;; A budget file gates by glob, first match wins.
+    (define budget-path (build-path temp-root "budgets.json"))
+    (call-with-output-file budget-path
+      (lambda (out)
+        (write-json
+         (hasheq 'rules
+                 (list (hasheq 'glob "*.dmg" 'max-bytes 2000)
+                       (hasheq 'glob "*" 'max-bytes 100000)))
+         out)))
+    (define gated (measure-size project #:budget-path budget-path))
+    (check-equal? (length (hash-ref gated 'violations)) 1)
+    (define violation (car (hash-ref gated 'violations)))
+    (check-true
+     (string-suffix?
+      (path->string (car violation)) "measured-0.1.0-macos.dmg"))
+    (check-equal? (cdr violation) (cons 3000 2000))
+
+    ;; A tight global budget flags everything; relaxing it clears the gate.
+    (call-with-output-file budget-path
+      #:exists 'truncate
+      (lambda (out)
+        (write-json
+         (hasheq 'rules (list (hasheq 'glob "*" 'max-bytes 200000)))
+         out)))
+    (check-equal? (hash-ref (measure-size project #:budget-path budget-path)
+                            'violations)
+                  '())
+
+    ;; A clean budget file without dist artifacts is an error, not an
+    ;; empty pass: measuring nothing would read as a green gate.
+    (define empty-root (build-path temp-root "empty"))
+    (make-directory* empty-root)
+    (call-with-output-file (build-path empty-root "rivet.rktd")
+      (lambda (out)
+        (displayln
+         "#hasheq((name . \"Empty\") (backend . \"app/backend.rkt\") (module . \"backend\") (entry . \"start\") (protocol . 1))"
+         out)))
+    (check-exn #rx"no packaged artifacts"
+               (lambda () (measure-size (load-project empty-root))))
+
+    ;; Malformed budget files fail loudly instead of gating nothing.
+    (define malformed (build-path temp-root "malformed.json"))
+    (call-with-output-file malformed
+      (lambda (out) (display "{\"rules\": [{\"glob\": \"*.dmg\"}]}" out)))
+    (check-exn #rx"must contain"
+               (lambda () (parse-budget-file malformed)))
+    (check-exn #rx"budget file .* does not exist"
+               (lambda () (parse-budget-file
+                           (build-path temp-root "absent.json"))))
+
+    ;; The artifact filter narrows a single row.
+    (define filtered
+      (measure-size project #:artifact "update-stable.json"))
+    (check-equal? (length (hash-ref filtered 'artifacts)) 1)
+    (check-equal?
+     (hash-ref (car (hash-ref filtered 'artifacts)) 'bytes)
+     40))
+
+  (lambda ()
+    (when (directory-exists? temp-root)
+      (delete-directory/files temp-root))))