How is the historical conversation resume feature implemented?

[Doraemonwei]

In the code, the interaction is achieved via codex proto, and it uses experimental_resume= to perform the resume. However, according to the official codex CLI documentation, the experimental_resume parameter is still in the internal testing stage. When I tried using codex proto -c experimental_resume={rollout-path} directly, I found that the resume did not succeed.

Therefore, I’d like to ask how this project actually implements the resume feature.

Thanks.

[milisp]

There's a resume button at the chat tab, you can click to resume the conversation from path.

But Codex change the rollout-path message type, so I have to change the function to parse the file again to show the right list. Currently only shows the old file format.

You can wait or create a PR.

You can ask codex: after I click the resume button and the list was wrong, read the files from ~/.codex/sessions and fix it.

log

[2025-09-25][15:16:53][codexia_lib::codex_client::command_builder][INFO] Built codex command: Command { std: "/Users/gpt/.bun/install/global/node_modules/@openai/codex/vendor/aarch64-apple-darwin/codex/codex" "proto" "-c" "model_provider=google" "-c" "base_url=https://generativelanguage.googleapis.com/v1beta/openai" "-c" "model=gemini-2.5-flash-lite" "-c" "model_reasoning_summary=auto" "-c" "approval_policy=on-request" "-c" "sandbox_mode=read-only" "-c" "model_reasoning_effort=minimal" "-c" "show_raw_agent_reasoning=true" "-c" "experimental_resume=\"/Users/gpt/.codex/sessions/2025/09/25/rollout-2025-09-25T11-16-01-01998172-170a-78a1-b842-687c468d13fb.jsonl\"" "-c" "cwd=/Users/gpt/pylang/demo", kill_on_drop: false }

Note

Resume Gap

• codex proto no longer checks any experimental_resume override; it always calls ConversationManager::new_conversation(...) and starts a fresh session (codex-rs/cli/src/
  proto.rs:37).
• The only place that still knows how to resume from a rollout file is the new resume flow that calls conversation_manager.resume_conversation_from_rollout(...) (codex-rs/exec/
  src/lib.rs:223 → codex-rs/core/src/conversation_manager.rs:114). That path is used by codex exec resume … / codex resume …, not by proto.
• Because of this, the resumePath we pass from ChatView never reaches the backend. CommandBuilder keeps launching codex proto with -c experimental_resume="…", but that flag is now
  ignored and the process always starts from scratch.

Implications for the Tauri app

• The existing start_codex_session flow cannot actually resume anything; the CLI threw away the hook we relied on. That’s why the Resume dialog no longer works even though it
  still reads rollout files correctly.
• To restore resume support we need a different integration point—either:
  1. drive the resume flow that codex exec resume … uses (and capture its JSON output with --json if we want structured events), or
  2. switch to the MCP server protocol (resumeConversation) which still exposes full resume machinery, or
  3. embed codex_core directly and call ConversationManager::resume_conversation_from_rollout.

[milisp]

Btw, there's a new way now — you can use codex app-server via app-server-protocol :)