workingDirectory is not supported with…

Error message

workingDirectory is not supported with RuntimeConnection.forInProcess(): the in-process transport hosts the runtime in this process, so honoring it would require mutating the shared process-global cwd. Change the host process's working directory before constructing the client instead.

What it means

After the session.create RPC completes, CopilotClient._register_inline() raises this RuntimeError if the response contains no session (sessionId). A well-formed server response must include a session id so the client can register and track the new session; a missing one indicates a malformed or unexpected server reply.

Solutions

Check client and copilot CLI/server versions and align them (the response schema may differ across versions).
Inspect the raw session.create response (enable debug logging) to see what the server returned.
Retry session creation; if it persists, report/fix the server-side response-shape regression.
Bypass proxies/intermediaries that may alter the RPC response body.

Example fix

// before
resp = await client.create_session(model="gpt-4o")  # empty sessionId
// after
# update CLI/server to a matching version, then:
session = await client.create_session(model="gpt-4o")
assert session.session_id

Defensive patterns

Strategy: try-catch

Type guard

def response_has_session(response: dict) -> bool:
    return bool(response.get("sessionId"))

Try / catch

try:
    session = await client.create_session(...)
except RuntimeError as e:
    if "sessionId" in str(e):
        ...  # log raw RPC response, retry once, then escalate

Prevention

Keep copilot CLI/server and SDK versions aligned.
Enable debug logging around session.create in integration tests.
Avoid intermediaries that can rewrite or truncate RPC responses.

When it happens

Trigger: The backend responds to session.create without a sessionId/session payload - e.g. server/CLI version mismatch, an error-shaped response treated as success, or a proxy returning an empty 200 body.

Common situations: Running against an older or newer copilot CLI server whose session.create reply shape differs; a gateway stripping the response body; transient backend faults producing empty replies.

Understand the failure class

Background: "invalid response format", "malformed payload", "missing data field": when an API returns 200 but the response shape is wrong — this error's family across 23 libraries.

Related errors

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/8149df612ccfff2a. Report an issue: GitHub.

Appendix: source

Thrown at nodejs/src/client.ts:613

    constructor(options: CopilotClientOptions = {}) {
        // Resolve the connection mode. `_internalConnection` is set by
        // `joinSession()` to opt into the parent-process stdio path; consumers
        // should always go through the public `connection` field.
        const conn: InternalRuntimeConnection =
            options._internalConnection ??
            options.connection ??
            CopilotClient.resolveDefaultConnection();

        if (
            conn.kind === "uri" &&
            (options.gitHubToken !== undefined || options.useLoggedInUser !== undefined)
        ) {
            throw new Error(
                "gitHubToken and useLoggedInUser cannot be used with RuntimeConnection.forUri (external server manages its own auth)"
            );
        }
        if (conn.kind === "inprocess" && options.workingDirectory !== undefined) {
            throw new Error(
                "workingDirectory is not supported with RuntimeConnection.forInProcess(): the in-process " +
                    "transport hosts the runtime in this process, so honoring it would require mutating the " +
                    "shared process-global cwd. Change the host process's working directory before " +
                    "constructing the client instead."
            );
        }
        if (conn.kind === "inprocess" && options.env !== undefined) {
            throw new Error(
                "env is not supported with RuntimeConnection.forInProcess(): the in-process transport loads " +
                    "the native runtime into the shared host process, whose single environment block cannot " +
                    "carry per-client values. Set the variables on the host process environment instead."
            );
        }
        if (conn.kind === "inprocess" && options.telemetry !== undefined) {
            throw new Error(
                "telemetry is not supported with RuntimeConnection.forInProcess(): telemetry configuration " +
                    "is lowered to environment variables read by native runtime code running in the shared " +
                    "host process, so per-client telemetry cannot be honored in-process. Configure telemetry " +

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