Method getSystemMessageConfigForMode

nodejs/src/client.ts:1206–1240

* Returns the systemMessage config to use, adjusted for the current mode. * In empty mode we ensure the environment_context section is removed * unless the app has already taken control of it. `append` (and * unspecified) mode is promoted to `customize` so we can also strip * env

(
        supplied: SystemMessageConfig | undefined
    )

     * customize and append modes.
     */
    private getSystemMessageConfigForMode(
        supplied: SystemMessageConfig | undefined
    ): SystemMessageConfig | undefined {
        if (this.options.mode !== "empty") return supplied;
        if (!supplied) {
            return {
                mode: "customize",
                sections: { environment_context: { action: "remove" } },
            };
        }
        switch (supplied.mode) {
            case "replace":
                return supplied;
            case "customize":
                if (supplied.sections?.environment_context) return supplied;
                return {
                    ...supplied,
                    sections: {
                        ...supplied.sections,
                        environment_context: { action: "remove" },
                    },
                };
            case "append":
            case undefined:
                // Promote to customize so we can also strip environment_context.
                // The runtime appends `content` to additional instructions in
                // both customize and append modes, so the caller's text is
                // preserved verbatim.
                return {
                    mode: "customize",
                    content: supplied.content,
                    sections: { environment_context: { action: "remove" } },
                };
        }
    }

    /**
     * Mode-specific options applied via session.options.update after create/resume.