Codex MCP Server: Fix Missing Conversation ID For Seamless Chat

The Missing Piece: conversationId in Codex MCP Server Responses

When you're building sophisticated AI workflows, especially those involving multi-turn conversations, having all the necessary pieces of information is crucial. One such critical piece is the conversationId. This unique identifier acts like a thread, tying together all the messages within a single dialogue. However, a notable issue has surfaced when using the codex mcp-server as an MCP server, particularly when integrated with platforms like Claude Code. The codex tool, in its current implementation, fails to return the conversationId in its response. This oversight makes it impossible to leverage the codex-reply tool effectively for continuous conversations. Without this ID, you're left scrambling to manually fish out the session ID from your filesystem, a process that's far from ideal for an automated workflow.

Imagine you're orchestrating a complex AI-to-AI collaboration. One AI agent, powered by Codex, is tasked with generating some code or text. The next agent needs to take that output and continue the conversation, perhaps by refining it or asking follow-up questions. This is where codex-reply would shine, enabling a fluid back-and-forth. But because the initial codex call only spits out the result text and omits the conversationId, the subsequent codex-reply call simply has no context to latch onto. It's like trying to continue a phone call without knowing who you're talking to or what the previous discussion was about. The conversationId is the linchpin that connects these sequential interactions, and its absence creates a significant roadblock for anyone aiming for seamless, automated conversational AI.

The current behavior is straightforwardly problematic. You make a call to the codex tool, and you receive your desired output text. Great! But then, when you try to use codex-reply to continue the conversation, it throws an error or simply doesn't work because it's desperately looking for that conversationId. This ID is expected to be in a UUID format, a standard for unique identifiers. The only place this elusive conversationId seems to be hiding is deep within your filesystem, buried in session log files. You'd have to navigate to ~/.codex/sessions/YYYY/MM/DD/ and meticulously parse filenames like rollout-{timestamp}-{SESSION_ID}.jsonl to extract the UUID. This is not just inconvenient; it actively undermines the purpose of an MCP server, which is to provide a standardized and programmatic way to interact with tools. Relying on manual filesystem parsing is brittle, error-prone, and completely unsuitable for production environments or any serious automation. It's a workaround that highlights a core functionality gap, preventing the Codex MCP server from fulfilling its potential in conversational scenarios.

The Seamless Experience: What We Expect

The expected behavior is elegantly simple and fundamentally necessary for conversational AI: the codex MCP tool's response should include the conversationId alongside the result text. This would transform the interaction from a disjointed series of calls into a coherent, continuous dialogue. Imagine the codex tool returning a JSON object that looks something like this:

{
  "result": "This is the generated text from Codex.",
  "conversationId": "019b63ce-02a4-7223-8d1d-f5dc6a1b4877"
}

With this conversationId readily available, the codex-reply tool could immediately pick it up and use it to form the next turn in the conversation. No digging through files, no complex parsing, just a clean, direct handoff of conversational context. This would enable developers to build applications where AI agents can hold natural, extended conversations without interruption or manual intervention. It’s the difference between a clunky, step-by-step process and a smooth, integrated experience.

This simple addition would unlock a wealth of possibilities. For instance, you could have an AI assistant that helps you write complex documents. The first call to codex might generate an outline. Subsequent calls, using codex-reply and the returned conversationId, could then flesh out each section, refine phrasing, and ensure consistency throughout the document. Similarly, in code generation scenarios, you might start with a function signature, and then use codex-reply to iteratively add implementation details, error handling, and documentation, all while maintaining the context of the original request. The conversationId is the key that allows the system to remember and build upon previous interactions, which is the essence of a true conversation.

Without this, the codex tool functions more like a one-off command processor rather than a conversational participant. The ability to chain requests and maintain state is paramount for any tool aiming to be part of a larger, interactive system. By including the conversationId, the Codex MCP server would align with the expectations of modern AI interaction patterns, making it a far more powerful and versatile component in any AI development stack. It's a small change with a significant impact on usability and functionality for anyone building conversational AI agents or workflows.

Recreating the Issue: A Step-by-Step Breakdown

To truly understand the impact of the missing conversationId, let's walk through the exact steps that lead to this roadblock. The process begins with the setup of the codex mcp-server. This involves configuring it within your existing MCP client environment. A common scenario, as mentioned, is integrating it with Claude Code, but the principle applies to any MCP client that utilizes the codex mcp-server as its backend. You'll typically have a configuration file, often named .mcp.json, where you specify the codex tool as a server. This setup essentially tells your MCP client, "When you need to use the codex tool, send the request to this local server."

Once the server is configured and running, the next step is to actually invoke the codex tool with a specific prompt. This is where you'd ask Codex to perform a task, like generating a piece of text, writing a code snippet, or answering a question. This call goes to the codex mcp-server, which processes the prompt and, according to the current implementation, returns the generated text as its primary output.

Here's the critical juncture: after receiving the result from the codex tool, you might want to continue the interaction. This is where codex-reply comes into play. The codex-reply tool is designed precisely for this purpose – to send a follow-up message within an existing conversation. However, and this is the core of the problem, codex-reply requires a conversationId to know which conversation it should append the new message to. Since the initial codex response did not include this conversationId, codex-reply has no way of identifying the ongoing session. Consequently, any attempt to use codex-reply at this stage will fail, as it lacks the essential context it needs to operate.

This leads directly to the workaround, which highlights the severity of the issue. Because the conversationId isn't returned programmatically, the only way to proceed with a multi-turn conversation is to manually extract this UUID from the filesystem. This involves navigating to the ~/.codex/sessions/ directory, which is organized by date. You then need to find the most recent session file (.jsonl extension) for the current day and parse its filename to isolate the SESSION_ID. This is a manual, error-prone, and time-consuming process that completely disrupts the intended workflow of an MCP server. It's a manual retrieval of session metadata that should, by all rights, be part of the tool's output. The reliance on this manual step underscores how the current design prevents seamless AI-to-AI collaboration, forcing developers to implement fragile workarounds instead of relying on a robust API.

The Manual Dig: A Glimpse into the Workaround

When the codex MCP tool fails to provide the conversationId, developers are forced to resort to a manual workaround to maintain conversational continuity. This workaround involves delving into the filesystem to retrieve the session identifier. The process typically looks something like this, often executed via a shell command:

ls -t ~/.codex/sessions/$(date +%Y)/$(date +%m)/$(date +%d)/*.jsonl | head -1 | \
  grep -oE '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}'

Let's break down what this command is doing. First, ~/.codex/sessions/$(date +%Y)/$(date +%m)/$(date +%d)/*.jsonl navigates to the directory where Codex stores its session logs. It uses shell commands to dynamically insert the current year, month, and day, ensuring you're looking in the correct daily folder. The *.jsonl wildcard targets all session log files within that directory.

Next, ls -t lists these files, sorted by modification time, with the most recent file appearing first. head -1 then selects only the very first (most recent) file from this sorted list. This is based on the assumption that the most recent file corresponds to the ongoing conversation you're interested in.

Finally, grep -oE '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}' is used to extract the actual conversationId (UUID) from the filename. The -o flag tells grep to only output the matched part, and -E enables extended regular expressions, making the pattern matching for the UUID format more straightforward. This pattern specifically looks for the standard 32-hexadecimal-character UUID format, separated by hyphens.

While this command successfully retrieves the needed conversationId, it's a clear indicator of a missing feature. This manual extraction is cumbersome, fragile (what if the filename format changes?), and completely defeats the purpose of having an API-driven MCP server. It turns a programmatic interaction into a manual step requiring shell expertise and filesystem access, which is undesirable for integration purposes. The expectation is that the tool itself would provide this vital piece of information directly in its output, streamlining the process and enabling true automation.

Environment Details

To accurately diagnose and resolve the issue concerning the missing conversationId in the codex MCP server's response, it's essential to detail the environment in which this problem is being observed. The Codex CLI version is specified as the latest available. This implies that the issue is not due to using an outdated version of the Codex command-line interface, but rather a potential design oversight or bug in the current, most up-to-date implementation. Keeping the CLI updated is generally recommended for accessing the latest features and bug fixes, so observing this problem on the latest version suggests it's a contemporary issue.

Crucially, the MCP integration is with Claude Code. This indicates that the codex mcp-server is acting as a backend for a specific client application designed for code-related tasks, likely leveraging Claude's capabilities. While the MCP protocol aims for standardization, specific integrations can sometimes expose unique behaviors or dependencies. Understanding that this problem occurs within the context of Claude Code integration helps narrow down the potential points of failure or miscommunication between the client and the server.

Finally, the Operating System is macOS. This information is important because system-level behaviors, file path conventions, and process management can differ across operating systems. While the core issue likely stems from the codex tool's logic, the specific manifestation or the workaround's implementation might be influenced by the underlying OS. For example, shell commands for file manipulation can have subtle variations. Knowing it's macOS confirms that the issue is reproducible on a widely used development platform and helps developers with similar setups identify with the problem description.

These environmental factors – the latest Codex CLI, integration with Claude Code, and a macOS operating system – paint a clear picture of the context. The expectation is that an MCP server, designed for programmatic interaction, should provide all necessary data for subsequent calls directly in its responses. The absence of the conversationId in this specific setup prevents seamless multi-turn conversations, a fundamental capability for many AI-driven applications.

The Ripple Effect: Impact on Conversational AI Workflows

The core impact of the codex MCP tool omitting the conversationId is the prevention of seamless multi-turn conversations. This is not a minor inconvenience; it strikes at the heart of what makes AI assistants and collaborative AI systems truly useful. In modern AI-to-AI collaboration workflows, the ability for agents to engage in extended dialogues, build upon previous turns, and maintain context is paramount. Without the conversationId, this seamless flow is impossible, forcing developers to implement cumbersome workarounds that undermine the efficiency and reliability of their systems.

Consider a scenario where you're using Codex as part of a larger automation pipeline. Perhaps one AI agent generates a complex query, and another agent needs to refine that query based on new information. The refinement process might involve multiple steps of interaction. If each step requires manual intervention to retrieve a session ID, the entire automation breaks down. The intended fluidity of AI-driven workflows is replaced by manual bottlenecks, significantly reducing the practical utility of the system. This makes complex tasks, which rely on iterative refinement and conversational context, extremely difficult, if not impossible, to implement effectively.

Furthermore, this limitation directly impacts the user experience. For applications built on top of the MCP server, users might experience broken conversational threads, unexpected errors, or a general lack of responsiveness. The expectation for any conversational interface, whether human-to-AI or AI-to-AI, is a natural and continuous interaction. When this continuity is broken due to a missing identifier, the application feels clunky and unreliable. This can lead to user frustration and a reduced adoption rate for tools that depend on this functionality.

In essence, the absence of the conversationId turns what should be a sophisticated conversational agent into a series of disconnected one-off requests. It limits the ability of AI agents to collaborate effectively, learn from past interactions, and perform complex, multi-step tasks that inherently require memory and context. This is a critical limitation for anyone developing advanced AI applications, from coding assistants and content generators to complex planning and reasoning systems. The ability to maintain a coherent conversational state is fundamental, and its absence here is a significant drawback for the utility and scalability of the codex mcp-server in conversational contexts.

Moving Forward: Towards a Connected Conversation

To address this critical limitation, the path forward is clear: the codex MCP tool must be updated to include the conversationId in its response. This is not merely a feature request; it is a fundamental requirement for enabling true conversational capabilities. By ensuring that the conversationId is part of the standard output, developers can seamlessly integrate codex-reply and build sophisticated, multi-turn interactions without resorting to brittle filesystem parsing or manual workarounds.

This enhancement would unlock the full potential of the codex mcp-server for AI-to-AI collaboration and complex workflow automation. It aligns the tool with the principles of good API design, where all necessary information for subsequent operations is provided directly. For anyone working with conversational AI, ensuring that conversationId is readily available is key to building robust and scalable applications.

For further insights into MCP protocols and AI development best practices, you might find valuable information on the OpenAI Developer Documentation and the LangChain Documentation.