@@ -55,13 +55,14 @@ the selected `.py` files sequentially to the current board directory.**
 3. **Directory browsing is lazy and selection is folder-scoped.** Resolving a
    repository does not recursively enumerate its tree. Opening a directory
    fetches only that directory at the pinned commit; Up is bounded at the repo
-   root. A selection contains direct children of one currently chosen remote
-   directory only. Changing directory clears it. Only Git-tree entries with an
-   ordinary blob mode (`100644` or `100755`) and a lowercase `.py` suffix are
-   eligible. Directories remain browsable; symlink mode `120000`, submodule
-   mode `160000`, non-files, `.mpy`, `.pyc`, and every other suffix are visible
-   only as ineligible or omitted and are never fetched or written by this
-   increment.
+   root. One response is capped at 2 MiB and 512 direct entries; exceeding
+   either limit rejects the folder before it reaches the eager tablet view. A
+   selection contains direct children of one currently chosen remote directory
+   only. Changing directory clears it. Only Git-tree entries with an ordinary
+   blob mode (`100644` or `100755`) and a lowercase `.py` suffix are eligible.
+   Directories remain browsable; symlink mode `120000`, submodule mode `160000`,
+   non-files, `.mpy`, `.pyc`, and every other suffix are visible only as
+   ineligible or omitted and are never fetched or written by this increment.
 
 4. **The board target is explicit and flat for this subset.** Opening the
    action captures the Files controller's current board directory (`cwd`).
@@ -124,7 +125,11 @@ the selected `.py` files sequentially to the current board directory.**
    offline/not-found/forbidden/rate-limit/server/malformed-response failures
    map to localized user actions. `403`/`429` rate limiting shows the public
    API limit and reset/retry guidance when GitHub supplies it; the app performs
-   no tight or unbounded automatic retry.
+   no tight or unbounded automatic retry. A positive supplied retry delay gates
+   every network-producing action on the surface until its deadline; local
+   navigation, selection, and review transitions cannot clear or bypass it.
+   Header-rejected HTTP responses have their body streams cancelled before the
+   typed failure is returned so repeated failures do not strand resources.
 
 10. **The surface is adaptive and accessible.** Import examples is an action
     on the connected Files surface, enabled only for a ready connection. Below
 
@@ -766,7 +766,10 @@ disabled (or independently revalidated and rejected unless the destination is
 the same exact host). It sends GitHub's required API version/accept/user-agent
 headers but no authorization, token, cookie, board fact, or user source. It
 does not follow `download_url`, HTML links, or any arbitrary URL returned in a
-response (SEC-10).
+response. A response rejected from headers alone (including status or declared
+body length) has its body stream cancelled before the adapter publishes the
+typed failure, so repeated hostile responses cannot strand transport resources
+(SEC-10).
 
 Resolution is a two-step logical operation:
 
@@ -782,6 +785,10 @@ from that tree. Thus every object is derived from the resolved commit without
 reading through the original moving ref or trusting a response URL. An
 explicit **Refresh ref** starts a new operation generation, resolves again, and
 clears directories, selection, candidate bytes, conflicts, and consent.
+Tree response bodies are capped at 2 MiB and each decoded non-recursive tree is
+rejected above 512 direct entries before the directory model reaches the eager
+tablet view. These are hard resource ceilings, not pagination: the subset never
+silently presents a partial folder.
 
 ### 10.3 Lazy browse, selection, and adaptive state
 
@@ -795,9 +802,10 @@ enterRepository → resolving → browsing → selecting → reviewing
 
 The implementation does not introduce a second Riverpod workflow controller.
 The adaptive `StatefulWidget` owns presentation-only state: a
-`browse | review | result` surface step, `resolving | loadingDirectory`
-network phase, directory stack, selection, failure/retry/focus data, and the
-current progress/result. Resolve/list operations capture the view's increasing
+`browse | review | result` surface step,
+`resolving | loadingDirectory | checkingBoardTargets` operation phase,
+directory stack, selection, failure/retry/focus data, and the current
+progress/result. Resolve/list operations capture the view's increasing
 epoch and a `GithubCancellation`; cancel, ref refresh, directory change, or
 disposal advances that epoch, and a late completion cannot repopulate the
 view. `GithubBoardImporter` separately owns its fetch/commit generation,
@@ -942,9 +950,14 @@ never echo fetched bytes.
 For `403`/`429`, the REST adapter captures bounded numeric rate-limit metadata
 (`remaining`, reset instant or retry delay when valid). The view explains the
 unauthenticated public limit and offers a user-driven retry after the supplied
-time. There is no automatic tight loop; transient retries, if later admitted,
-must be separately bounded and cancellable. Ordinary GitHub failure does not
-disable Files, Editor, Run, or any offline workflow (NFR-OFF-2).
+time. A positive supplied delay establishes one surface-wide not-before
+deadline independent of the currently rendered error object. Repository/ref
+edits, folder navigation, selection changes, review entry/cancellation, and
+other local state transitions cannot shorten or clear it; every action that can
+start a GitHub request is disabled and guarded until it expires. There is no
+automatic tight loop; transient retries, if later admitted, must be separately
+bounded and cancellable. Ordinary GitHub failure does not disable Files,
+Editor, Run, or any offline workflow (NFR-OFF-2).
 
 ### 10.7 Explicit deferred full-A-33 design
 
 
@@ -226,12 +226,14 @@ to `[red]` before implementation:
   MUST
 - **A33-SUB-AC-3 (lazy folder-scoped browse)** — The client MUST load only the
   opened directory at the pinned commit; it MUST NOT recursively enumerate the
-  repository. Up MUST be bounded at repository root. Multi-selection MUST be
-  limited to direct, eligible children of one chosen remote directory, and a
-  directory change MUST clear it. Only GitHub-confirmed regular files with a
-  lowercase `.py` suffix are eligible; directories MAY be opened, while
-  symlinks, submodules, non-files, `.mpy`, `.pyc`, and other suffixes MUST NOT
-  be selected, fetched, or written. MUST
+  repository. A non-recursive tree response MUST be at most 2 MiB and contain
+  at most 512 direct entries; a larger response MUST fail closed before entries
+  are published to the eager tablet view. Up MUST be bounded at repository
+  root. Multi-selection MUST be limited to direct, eligible children of one
+  chosen remote directory, and a directory change MUST clear it. Only
+  GitHub-confirmed regular files with a lowercase `.py` suffix are eligible;
+  directories MAY be opened, while symlinks, submodules, non-files, `.mpy`,
+  `.pyc`, and other suffixes MUST NOT be selected, fetched, or written. MUST
 - **A33-SUB-AC-4 (exact targets and overwrite consent)** — Review MUST show
   every exact remote path and its exact board target
   `join(capturedCwd, basename(remotePath))`. This subset MUST NOT preserve the
@@ -276,9 +278,12 @@ to `[red]` before implementation:
   forbidden, rate-limited, server, malformed-response, validation, board, and
   stale-session failures MUST map to distinct localized, actionable messages.
   A GitHub `403`/`429` MUST show bounded retry/reset guidance when the response
-  supplies it; the importer MUST NOT tight-loop or retry without a bound and an
-  explicit user action. Browse/fetch loading MUST retain location and selection
-  context without presenting stale data as current. MUST
+  supplies it. A positive server-supplied retry delay MUST gate every network-
+  producing action on that import surface until its deadline; navigation,
+  selection, review cancellation, or another local state transition MUST NOT
+  clear or bypass it. The importer MUST NOT tight-loop or retry without a bound
+  and an explicit user action. Browse/fetch loading MUST retain location and
+  selection context without presenting stale data as current. MUST
 - **A33-SUB-AC-9 (accessibility)** — All visible and semantic text MUST come
   from ARB except ASCII technical URL/ref/SHA/path values. Fields, directory
   rows, file eligibility/selection, loading, pinned SHA, target mappings,