Felipe Coury
ec8d4bfc77
## Problem When a user resumed or forked a session, the TUI could render the restored thread history immediately, but it did not receive token usage until a later model turn emitted a fresh usage event. That left the context/status UI blank or stale during the exact window where the user expects resumed state to look complete. Core already reconstructed token usage from the rollout; the missing behavior was app-server lifecycle replay to the client that just attached. ## Mental model Token usage has two representations. The rollout is the durable source of historical `TokenCount` events, and the core session cache is the in-memory snapshot reconstructed from that rollout on resume or fork. App-server v2 clients do not read core state directly; they learn about usage through `thread/tokenUsage/updated`. The fix keeps those roles separate: core exposes the restored `TokenUsageInfo`, and app-server sends one targeted notification after a successful `thread/resume` or `thread/fork` response when that restored snapshot exists. This notification is not a new model event. It is a replay of already-persisted state for the client that just attached. That distinction matters because using the normal core event path here would risk duplicating `TokenCount` entries in the rollout and making future resumes count historical usage twice. ## Non-goals This change does not add a new protocol method or payload shape. It reuses the existing v2 `thread/tokenUsage/updated` notification and the TUI’s existing handler for that notification. This change does not alter how token usage is computed, accumulated, compacted, or written during turns. It only exposes the token usage that resume and fork reconstruction already restored. This change does not broadcast historical usage replay to every subscribed client. The replay is intentionally scoped to the connection that requested resume or fork so already-attached clients are not surprised by an old usage update while they may be rendering live activity. ## Tradeoffs Sending the usage notification after the JSON-RPC response preserves a clear lifecycle order: the client first receives the thread object, then receives restored usage for that thread. The tradeoff is that usage is still a notification rather than part of the `thread/resume` or `thread/fork` response. That keeps the protocol shape stable and avoids duplicating usage fields across response types, but clients must continue listening for notifications after receiving the response. The helper selects the latest non-in-progress turn id for the replayed usage notification. This is conservative because restored usage belongs to completed persisted accounting, not to newly attached in-flight work. The fallback to the last turn preserves a stable wire payload for unusual histories, but histories with no meaningful completed turn still have a weak attribution story. ## Architecture Core already seeds `Session` token state from the last persisted rollout `TokenCount` during `InitialHistory::Resumed` and `InitialHistory::Forked`. The new core accessor exposes the complete `TokenUsageInfo` through `CodexThread` without giving app-server direct session mutation authority. App-server calls that accessor from three lifecycle paths: cold `thread/resume`, running-thread resume/rejoin, and `thread/fork`. In each path, the server sends the normal response first, then calls a shared helper that converts core usage into `ThreadTokenUsageUpdatedNotification` and sends it only to the requesting connection. The tests build fake rollouts with a user turn plus a persisted token usage event. They then exercise `thread/resume` and `thread/fork` without starting another model turn, proving that restored usage arrives before any next-turn token event could be produced. ## Observability The primary debug path is the app-server JSON-RPC stream. After `thread/resume` or `thread/fork`, a client should see the response followed by `thread/tokenUsage/updated` when the source rollout includes token usage. If the notification is absent, check whether the rollout contains an `event_msg` payload of type `token_count`, whether core reconstruction seeded `Session::token_usage_info`, and whether the connection stayed attached long enough to receive the targeted notification. The notification is sent through the existing `OutgoingMessageSender::send_server_notification_to_connections` path, so existing app-server tracing around server notifications still applies. Because this is a replay, not a model turn event, debugging should start at the resume/fork handlers rather than the turn event translation in `bespoke_event_handling`. ## Tests The focused regression coverage is `cargo test -p codex-app-server emits_restored_token_usage`, which covers both resume and fork. The core reconstruction guard is `cargo test -p codex-core record_initial_history_seeds_token_info_from_rollout`. Formatting and lint/fix passes were run with `just fmt`, `just fix -p codex-core`, and `just fix -p codex-app-server`. Full crate test runs surfaced pre-existing unrelated failures in command execution and plugin marketplace tests; the new token usage tests passed in focused runs and within the app-server suite before the unrelated command execution failure.
codex-core
This crate implements the business logic for Codex. It is designed to be used by the various Codex UIs written in Rust.
Dependencies
Note that codex-core makes some assumptions about certain helper utilities being available in the environment. Currently, this support matrix is:
macOS
Expects /usr/bin/sandbox-exec to be present.
When using the workspace-write sandbox policy, the Seatbelt profile allows
writes under the configured writable roots while keeping .git (directory or
pointer file), the resolved gitdir: target, and .codex read-only.
Network access and filesystem read/write roots are controlled by
SandboxPolicy. Seatbelt consumes the resolved policy and enforces it.
Seatbelt also keeps the legacy default preferences read access
(user-preference-read) needed for cfprefs-backed macOS behavior.
Linux
Expects the binary containing codex-core to run the equivalent of codex sandbox linux (legacy alias: codex debug landlock) when arg0 is codex-linux-sandbox. See the codex-arg0 crate for details.
Legacy SandboxPolicy / sandbox_mode configs are still supported on Linux.
They can continue to use the legacy Landlock path when the split filesystem
policy is sandbox-equivalent to the legacy model after cwd resolution.
Split filesystem policies that need direct FileSystemSandboxPolicy
enforcement, such as read-only or denied carveouts under a broader writable
root, automatically route through bubblewrap. The legacy Landlock path is used
only when the split filesystem policy round-trips through the legacy
SandboxPolicy model without changing semantics. That includes overlapping
cases like /repo = write, /repo/a = none, /repo/a/b = write, where the
more specific writable child must reopen under a denied parent.
The Linux sandbox helper prefers the first bwrap found on PATH outside the
current working directory whenever it is available. If bwrap is present but
too old to support --argv0, the helper keeps using system bubblewrap and
switches to a no---argv0 compatibility path for the inner re-exec. If
bwrap is missing, it falls back to the vendored bubblewrap path compiled into
the binary and Codex surfaces a startup warning through its normal notification
path instead of printing directly from the sandbox helper. Codex also surfaces
a startup warning when bubblewrap cannot create user namespaces. WSL2 uses the
normal Linux bubblewrap path. WSL1 is not supported for bubblewrap sandboxing
because it cannot create the required user namespaces, so Codex rejects
sandboxed shell commands that would enter the bubblewrap path before invoking
bwrap.
Windows
Legacy SandboxPolicy / sandbox_mode configs are still supported on
Windows.
The elevated setup/runner backend supports legacy ReadOnlyAccess::Restricted
for read-only and workspace-write policies. Restricted read access honors
explicit readable roots plus the command cwd, and keeps writable roots
readable when workspace-write is used.
When include_platform_defaults = true, the elevated Windows backend adds
backend-managed system read roots required for basic execution, such as
C:\Windows, C:\Program Files, C:\Program Files (x86), and
C:\ProgramData. When it is false, those extra system roots are omitted.
The elevated Windows sandbox also supports:
- legacy
ReadOnlyandWorkspaceWritebehavior - split filesystem policies that need exact readable roots, exact writable roots, or extra read-only carveouts under writable roots
The unelevated restricted-token backend still supports the legacy full-read
Windows model for legacy ReadOnly and WorkspaceWrite behavior. It also
supports a narrow split-filesystem subset: full-read split policies whose
writable roots still match the legacy WorkspaceWrite root set, but add extra
read-only carveouts under those writable roots.
New [permissions] / split filesystem policies remain supported on Windows
only when they can be enforced directly by the selected Windows backend or
round-trip through the legacy SandboxPolicy model without changing semantics.
Policies that would require direct explicit unreadable carveouts (none) or
reopened writable descendants under read-only carveouts still fail closed
instead of running with weaker enforcement.
All Platforms
Expects the binary containing codex-core to simulate the virtual
apply_patch CLI when arg1 is --codex-run-as-apply-patch. See the
codex-arg0 crate for details.